`.\r\n * @returns {Function} A `useDispatch` hook bound to the specified context.\r\n */\n\nexport function createDispatchHook(context) {\n if (context === void 0) {\n context = ReactReduxContext;\n }\n\n var useStore = context === ReactReduxContext ? useDefaultStore : createStoreHook(context);\n return function useDispatch() {\n var store = useStore();\n return store.dispatch;\n };\n}\n/**\r\n * A hook to access the redux `dispatch` function.\r\n *\r\n * @returns {any|function} redux store's `dispatch` function\r\n *\r\n * @example\r\n *\r\n * import React, { useCallback } from 'react'\r\n * import { useDispatch } from 'react-redux'\r\n *\r\n * export const CounterComponent = ({ value }) => {\r\n * const dispatch = useDispatch()\r\n * const increaseCounter = useCallback(() => dispatch({ type: 'increase-counter' }), [])\r\n * return (\r\n * \r\n * {value}\r\n * \r\n *
\r\n * )\r\n * }\r\n */\n\nexport var useDispatch =\n/*#__PURE__*/\ncreateDispatchHook();","import { useReducer, useRef, useMemo, useContext } from 'react';\nimport { useReduxContext as useDefaultReduxContext } from './useReduxContext';\nimport Subscription from '../utils/Subscription';\nimport { useIsomorphicLayoutEffect } from '../utils/useIsomorphicLayoutEffect';\nimport { ReactReduxContext } from '../components/Context';\n\nvar refEquality = function refEquality(a, b) {\n return a === b;\n};\n\nfunction useSelectorWithStoreAndSubscription(selector, equalityFn, store, contextSub) {\n var _useReducer = useReducer(function (s) {\n return s + 1;\n }, 0),\n forceRender = _useReducer[1];\n\n var subscription = useMemo(function () {\n return new Subscription(store, contextSub);\n }, [store, contextSub]);\n var latestSubscriptionCallbackError = useRef();\n var latestSelector = useRef();\n var latestSelectedState = useRef();\n var selectedState;\n\n try {\n if (selector !== latestSelector.current || latestSubscriptionCallbackError.current) {\n selectedState = selector(store.getState());\n } else {\n selectedState = latestSelectedState.current;\n }\n } catch (err) {\n if (latestSubscriptionCallbackError.current) {\n err.message += \"\\nThe error may be correlated with this previous error:\\n\" + latestSubscriptionCallbackError.current.stack + \"\\n\\n\";\n }\n\n throw err;\n }\n\n useIsomorphicLayoutEffect(function () {\n latestSelector.current = selector;\n latestSelectedState.current = selectedState;\n latestSubscriptionCallbackError.current = undefined;\n });\n useIsomorphicLayoutEffect(function () {\n function checkForUpdates() {\n try {\n var newSelectedState = latestSelector.current(store.getState());\n\n if (equalityFn(newSelectedState, latestSelectedState.current)) {\n return;\n }\n\n latestSelectedState.current = newSelectedState;\n } catch (err) {\n // we ignore all errors here, since when the component\n // is re-rendered, the selectors are called again, and\n // will throw again, if neither props nor store state\n // changed\n latestSubscriptionCallbackError.current = err;\n }\n\n forceRender({});\n }\n\n subscription.onStateChange = checkForUpdates;\n subscription.trySubscribe();\n checkForUpdates();\n return function () {\n return subscription.tryUnsubscribe();\n };\n }, [store, subscription]);\n return selectedState;\n}\n/**\r\n * Hook factory, which creates a `useSelector` hook bound to a given context.\r\n *\r\n * @param {React.Context} [context=ReactReduxContext] Context passed to your ``.\r\n * @returns {Function} A `useSelector` hook bound to the specified context.\r\n */\n\n\nexport function createSelectorHook(context) {\n if (context === void 0) {\n context = ReactReduxContext;\n }\n\n var useReduxContext = context === ReactReduxContext ? useDefaultReduxContext : function () {\n return useContext(context);\n };\n return function useSelector(selector, equalityFn) {\n if (equalityFn === void 0) {\n equalityFn = refEquality;\n }\n\n if (process.env.NODE_ENV !== 'production' && !selector) {\n throw new Error(\"You must pass a selector to useSelectors\");\n }\n\n var _useReduxContext = useReduxContext(),\n store = _useReduxContext.store,\n contextSub = _useReduxContext.subscription;\n\n return useSelectorWithStoreAndSubscription(selector, equalityFn, store, contextSub);\n };\n}\n/**\r\n * A hook to access the redux store's state. This hook takes a selector function\r\n * as an argument. The selector is called with the store state.\r\n *\r\n * This hook takes an optional equality comparison function as the second parameter\r\n * that allows you to customize the way the selected state is compared to determine\r\n * whether the component needs to be re-rendered.\r\n *\r\n * @param {Function} selector the selector function\r\n * @param {Function=} equalityFn the function that will be used to determine equality\r\n *\r\n * @returns {any} the selected state\r\n *\r\n * @example\r\n *\r\n * import React from 'react'\r\n * import { useSelector } from 'react-redux'\r\n *\r\n * export const CounterComponent = () => {\r\n * const counter = useSelector(state => state.counter)\r\n * return {counter}
\r\n * }\r\n */\n\nexport var useSelector =\n/*#__PURE__*/\ncreateSelectorHook();","import Provider from './components/Provider';\nimport connectAdvanced from './components/connectAdvanced';\nimport { ReactReduxContext } from './components/Context';\nimport connect from './connect/connect';\nimport { useDispatch, createDispatchHook } from './hooks/useDispatch';\nimport { useSelector, createSelectorHook } from './hooks/useSelector';\nimport { useStore, createStoreHook } from './hooks/useStore';\nimport { setBatch } from './utils/batch';\nimport { unstable_batchedUpdates as batch } from './utils/reactBatchedUpdates';\nimport shallowEqual from './utils/shallowEqual';\nsetBatch(batch);\nexport { Provider, connectAdvanced, ReactReduxContext, connect, batch, useDispatch, createDispatchHook, useSelector, createSelectorHook, useStore, createStoreHook, shallowEqual };","import arrayWithoutHoles from \"./arrayWithoutHoles.js\";\nimport iterableToArray from \"./iterableToArray.js\";\nimport unsupportedIterableToArray from \"./unsupportedIterableToArray.js\";\nimport nonIterableSpread from \"./nonIterableSpread.js\";\nexport default function _toConsumableArray(arr) {\n return arrayWithoutHoles(arr) || iterableToArray(arr) || unsupportedIterableToArray(arr) || nonIterableSpread();\n}","import arrayLikeToArray from \"./arrayLikeToArray.js\";\nexport default function _arrayWithoutHoles(arr) {\n if (Array.isArray(arr)) return arrayLikeToArray(arr);\n}","export default function _nonIterableSpread() {\n throw new TypeError(\"Invalid attempt to spread non-iterable instance.\\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method.\");\n}","/* eslint-disable no-console */\nvar warned = {};\nexport function warning(valid, message) {\n // Support uglify\n if (process.env.NODE_ENV !== 'production' && !valid && console !== undefined) {\n console.error(\"Warning: \".concat(message));\n }\n}\nexport function note(valid, message) {\n // Support uglify\n if (process.env.NODE_ENV !== 'production' && !valid && console !== undefined) {\n console.warn(\"Note: \".concat(message));\n }\n}\nexport function resetWarned() {\n warned = {};\n}\nexport function call(method, valid, message) {\n if (!valid && !warned[message]) {\n method(false, message);\n warned[message] = true;\n }\n}\nexport function warningOnce(valid, message) {\n call(warning, valid, message);\n}\nexport function noteOnce(valid, message) {\n call(note, valid, message);\n}\nexport default warningOnce;\n/* eslint-enable */","import devWarning, { resetWarned } from \"rc-util/es/warning\";\nexport { resetWarned };\nexport default (function (valid, component, message) {\n devWarning(valid, \"[antd: \".concat(component, \"] \").concat(message));\n});",null,"/**\n * @license\n * Copyright 2019 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { ErrorFactory, FirebaseError } from '@firebase/util';\n\nexport const enum ErrorCode {\n REGISTRATION_WINDOW = 'registration-window',\n REGISTRATION_PROJECT_ID = 'registration-project-id',\n REGISTRATION_API_KEY = 'registration-api-key',\n REGISTRATION_APP_ID = 'registration-app-id',\n STORAGE_OPEN = 'storage-open',\n STORAGE_GET = 'storage-get',\n STORAGE_SET = 'storage-set',\n STORAGE_DELETE = 'storage-delete',\n FETCH_NETWORK = 'fetch-client-network',\n FETCH_TIMEOUT = 'fetch-timeout',\n FETCH_THROTTLE = 'fetch-throttle',\n FETCH_PARSE = 'fetch-client-parse',\n FETCH_STATUS = 'fetch-status'\n}\n\nconst ERROR_DESCRIPTION_MAP: { readonly [key in ErrorCode]: string } = {\n [ErrorCode.REGISTRATION_WINDOW]:\n 'Undefined window object. This SDK only supports usage in a browser environment.',\n [ErrorCode.REGISTRATION_PROJECT_ID]:\n 'Undefined project identifier. Check Firebase app initialization.',\n [ErrorCode.REGISTRATION_API_KEY]:\n 'Undefined API key. Check Firebase app initialization.',\n [ErrorCode.REGISTRATION_APP_ID]:\n 'Undefined app identifier. Check Firebase app initialization.',\n [ErrorCode.STORAGE_OPEN]:\n 'Error thrown when opening storage. Original error: {$originalErrorMessage}.',\n [ErrorCode.STORAGE_GET]:\n 'Error thrown when reading from storage. Original error: {$originalErrorMessage}.',\n [ErrorCode.STORAGE_SET]:\n 'Error thrown when writing to storage. Original error: {$originalErrorMessage}.',\n [ErrorCode.STORAGE_DELETE]:\n 'Error thrown when deleting from storage. Original error: {$originalErrorMessage}.',\n [ErrorCode.FETCH_NETWORK]:\n 'Fetch client failed to connect to a network. Check Internet connection.' +\n ' Original error: {$originalErrorMessage}.',\n [ErrorCode.FETCH_TIMEOUT]:\n 'The config fetch request timed out. ' +\n ' Configure timeout using \"fetchTimeoutMillis\" SDK setting.',\n [ErrorCode.FETCH_THROTTLE]:\n 'The config fetch request timed out while in an exponential backoff state.' +\n ' Configure timeout using \"fetchTimeoutMillis\" SDK setting.' +\n ' Unix timestamp in milliseconds when fetch request throttling ends: {$throttleEndTimeMillis}.',\n [ErrorCode.FETCH_PARSE]:\n 'Fetch client could not parse response.' +\n ' Original error: {$originalErrorMessage}.',\n [ErrorCode.FETCH_STATUS]:\n 'Fetch server returned an HTTP error status. HTTP status: {$httpStatus}.'\n};\n\n// Note this is effectively a type system binding a code to params. This approach overlaps with the\n// role of TS interfaces, but works well for a few reasons:\n// 1) JS is unaware of TS interfaces, eg we can't test for interface implementation in JS\n// 2) callers should have access to a human-readable summary of the error and this interpolates\n// params into an error message;\n// 3) callers should be able to programmatically access data associated with an error, which\n// ErrorData provides.\ninterface ErrorParams {\n [ErrorCode.STORAGE_OPEN]: { originalErrorMessage: string | undefined };\n [ErrorCode.STORAGE_GET]: { originalErrorMessage: string | undefined };\n [ErrorCode.STORAGE_SET]: { originalErrorMessage: string | undefined };\n [ErrorCode.STORAGE_DELETE]: { originalErrorMessage: string | undefined };\n [ErrorCode.FETCH_NETWORK]: { originalErrorMessage: string };\n [ErrorCode.FETCH_THROTTLE]: { throttleEndTimeMillis: number };\n [ErrorCode.FETCH_PARSE]: { originalErrorMessage: string };\n [ErrorCode.FETCH_STATUS]: { httpStatus: number };\n}\n\nexport const ERROR_FACTORY = new ErrorFactory(\n 'remoteconfig' /* service */,\n 'Remote Config' /* service name */,\n ERROR_DESCRIPTION_MAP\n);\n\n// Note how this is like typeof/instanceof, but for ErrorCode.\nexport function hasErrorCode(e: Error, errorCode: ErrorCode): boolean {\n return e instanceof FirebaseError && e.code.indexOf(errorCode) !== -1;\n}\n","/**\n * @license\n * Copyright 2019 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nexport const ANALYTICS_ID_FIELD = 'measurementId';\n\n// Key to attach FID to in gtag params.\nexport const GA_FID_KEY = 'firebase_id';\nexport const ORIGIN_KEY = 'origin';\n\nexport const GTAG_URL = 'https://www.googletagmanager.com/gtag/js';\n\nexport enum GtagCommand {\n EVENT = 'event',\n SET = 'set',\n CONFIG = 'config'\n}\n\n/*\n * Officially recommended event names for gtag.js\n * Any other string is also allowed.\n */\nexport enum EventName {\n ADD_SHIPPING_INFO = 'add_shipping_info',\n ADD_PAYMENT_INFO = 'add_payment_info',\n ADD_TO_CART = 'add_to_cart',\n ADD_TO_WISHLIST = 'add_to_wishlist',\n BEGIN_CHECKOUT = 'begin_checkout',\n /** @deprecated */\n CHECKOUT_PROGRESS = 'checkout_progress',\n EXCEPTION = 'exception',\n GENERATE_LEAD = 'generate_lead',\n LOGIN = 'login',\n PAGE_VIEW = 'page_view',\n PURCHASE = 'purchase',\n REFUND = 'refund',\n REMOVE_FROM_CART = 'remove_from_cart',\n SCREEN_VIEW = 'screen_view',\n SEARCH = 'search',\n SELECT_CONTENT = 'select_content',\n SELECT_ITEM = 'select_item',\n SELECT_PROMOTION = 'select_promotion',\n /** @deprecated */\n SET_CHECKOUT_OPTION = 'set_checkout_option',\n SHARE = 'share',\n SIGN_UP = 'sign_up',\n TIMING_COMPLETE = 'timing_complete',\n VIEW_CART = 'view_cart',\n VIEW_ITEM = 'view_item',\n VIEW_ITEM_LIST = 'view_item_list',\n VIEW_PROMOTION = 'view_promotion',\n VIEW_SEARCH_RESULTS = 'view_search_results'\n}\n","/**\n * @license\n * Copyright 2019 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { Logger } from '@firebase/logger';\n\nexport const logger = new Logger('@firebase/analytics');\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport {\n FirebaseApp,\n FirebaseOptions,\n FirebaseAppConfig\n} from '@firebase/app-types';\nimport {\n _FirebaseApp,\n _FirebaseNamespace,\n FirebaseService\n} from '@firebase/app-types/private';\nimport { deepCopy } from '@firebase/util';\nimport {\n ComponentContainer,\n Component,\n ComponentType,\n Name\n} from '@firebase/component';\nimport { AppError, ERROR_FACTORY } from './errors';\nimport { DEFAULT_ENTRY_NAME } from './constants';\nimport { logger } from './logger';\n\n/**\n * Global context object for a collection of services using\n * a shared authentication state.\n */\nexport class FirebaseAppImpl implements FirebaseApp {\n private readonly options_: FirebaseOptions;\n private readonly name_: string;\n private isDeleted_ = false;\n private automaticDataCollectionEnabled_: boolean;\n private container: ComponentContainer;\n\n constructor(\n options: FirebaseOptions,\n config: FirebaseAppConfig,\n private readonly firebase_: _FirebaseNamespace\n ) {\n this.name_ = config.name!;\n this.automaticDataCollectionEnabled_ =\n config.automaticDataCollectionEnabled || false;\n this.options_ = deepCopy(options);\n this.container = new ComponentContainer(config.name!);\n\n // add itself to container\n this._addComponent(new Component('app', () => this, ComponentType.PUBLIC));\n // populate ComponentContainer with existing components\n for (const component of this.firebase_.INTERNAL.components.values()) {\n this._addComponent(component);\n }\n }\n\n get automaticDataCollectionEnabled(): boolean {\n this.checkDestroyed_();\n return this.automaticDataCollectionEnabled_;\n }\n\n set automaticDataCollectionEnabled(val) {\n this.checkDestroyed_();\n this.automaticDataCollectionEnabled_ = val;\n }\n\n get name(): string {\n this.checkDestroyed_();\n return this.name_;\n }\n\n get options(): FirebaseOptions {\n this.checkDestroyed_();\n return this.options_;\n }\n\n delete(): Promise {\n return new Promise(resolve => {\n this.checkDestroyed_();\n resolve();\n })\n .then(() => {\n this.firebase_.INTERNAL.removeApp(this.name_);\n\n return Promise.all(\n this.container.getProviders().map(provider => provider.delete())\n );\n })\n .then((): void => {\n this.isDeleted_ = true;\n });\n }\n\n /**\n * Return a service instance associated with this app (creating it\n * on demand), identified by the passed instanceIdentifier.\n *\n * NOTE: Currently storage and functions are the only ones that are leveraging this\n * functionality. They invoke it by calling:\n *\n * ```javascript\n * firebase.app().storage('STORAGE BUCKET ID')\n * ```\n *\n * The service name is passed to this already\n * @internal\n */\n _getService(\n name: string,\n instanceIdentifier: string = DEFAULT_ENTRY_NAME\n ): FirebaseService {\n this.checkDestroyed_();\n\n // getImmediate will always succeed because _getService is only called for registered components.\n return (this.container.getProvider(name as Name).getImmediate({\n identifier: instanceIdentifier\n }) as unknown) as FirebaseService;\n }\n /**\n * Remove a service instance from the cache, so we will create a new instance for this service\n * when people try to get this service again.\n *\n * NOTE: currently only firestore is using this functionality to support firestore shutdown.\n *\n * @param name The service name\n * @param instanceIdentifier instance identifier in case multiple instances are allowed\n * @internal\n */\n _removeServiceInstance(\n name: string,\n instanceIdentifier: string = DEFAULT_ENTRY_NAME\n ): void {\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n this.container.getProvider(name as any).clearInstance(instanceIdentifier);\n }\n\n /**\n * @param component the component being added to this app's container\n */\n _addComponent(component: Component): void {\n try {\n this.container.addComponent(component);\n } catch (e) {\n logger.debug(\n `Component ${component.name} failed to register with FirebaseApp ${this.name}`,\n e\n );\n }\n }\n\n _addOrOverwriteComponent(component: Component): void {\n this.container.addOrOverwriteComponent(component);\n }\n\n /**\n * This function will throw an Error if the App has already been deleted -\n * use before performing API actions on the App.\n */\n private checkDestroyed_(): void {\n if (this.isDeleted_) {\n throw ERROR_FACTORY.create(AppError.APP_DELETED, { appName: this.name_ });\n }\n }\n}\n\n// Prevent dead-code elimination of these methods w/o invalid property\n// copying.\n(FirebaseAppImpl.prototype.name && FirebaseAppImpl.prototype.options) ||\n FirebaseAppImpl.prototype.delete ||\n console.log('dc');\n","/**\n * @license\n * Copyright 2019 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { FirebaseNamespace } from '@firebase/app-types';\nimport { _FirebaseApp, _FirebaseNamespace } from '@firebase/app-types/private';\nimport { createSubscribe, deepExtend, ErrorFactory } from '@firebase/util';\nimport { FirebaseAppImpl } from './firebaseApp';\nimport { createFirebaseNamespaceCore } from './firebaseNamespaceCore';\n\n/**\n * Return a firebase namespace object.\n *\n * In production, this will be called exactly once and the result\n * assigned to the 'firebase' global. It may be called multiple times\n * in unit tests.\n */\nexport function createFirebaseNamespace(): FirebaseNamespace {\n const namespace = createFirebaseNamespaceCore(FirebaseAppImpl);\n (namespace as _FirebaseNamespace).INTERNAL = {\n ...(namespace as _FirebaseNamespace).INTERNAL,\n createFirebaseNamespace,\n extendNamespace,\n createSubscribe,\n ErrorFactory,\n deepExtend\n };\n\n /**\n * Patch the top-level firebase namespace with additional properties.\n *\n * firebase.INTERNAL.extendNamespace()\n */\n function extendNamespace(props: { [prop: string]: unknown }): void {\n deepExtend(namespace, props);\n }\n\n return namespace;\n}\n\nexport const firebase = createFirebaseNamespace();\n","/**\n * @license\n * Copyright 2019 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport {\n FirebaseApp,\n FirebaseOptions,\n FirebaseNamespace,\n FirebaseAppConfig\n} from '@firebase/app-types';\nimport {\n _FirebaseApp,\n _FirebaseNamespace,\n FirebaseService,\n FirebaseServiceNamespace\n} from '@firebase/app-types/private';\nimport { deepExtend, contains } from '@firebase/util';\nimport { FirebaseAppImpl } from './firebaseApp';\nimport { ERROR_FACTORY, AppError } from './errors';\nimport { FirebaseAppLiteImpl } from './lite/firebaseAppLite';\nimport { DEFAULT_ENTRY_NAME, PLATFORM_LOG_STRING } from './constants';\nimport { version } from '../../firebase/package.json';\nimport { logger } from './logger';\nimport {\n setUserLogHandler,\n setLogLevel,\n LogCallback,\n LogOptions\n} from '@firebase/logger';\nimport { Component, ComponentType, Name } from '@firebase/component';\n\n/**\n * Because auth can't share code with other components, we attach the utility functions\n * in an internal namespace to share code.\n * This function return a firebase namespace object without\n * any utility functions, so it can be shared between the regular firebaseNamespace and\n * the lite version.\n */\nexport function createFirebaseNamespaceCore(\n firebaseAppImpl: typeof FirebaseAppImpl | typeof FirebaseAppLiteImpl\n): FirebaseNamespace {\n const apps: { [name: string]: FirebaseApp } = {};\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n const components = new Map>();\n\n // A namespace is a plain JavaScript Object.\n const namespace: FirebaseNamespace = {\n // Hack to prevent Babel from modifying the object returned\n // as the firebase namespace.\n // @ts-ignore\n __esModule: true,\n initializeApp,\n // @ts-ignore\n app,\n registerVersion,\n setLogLevel,\n onLog,\n // @ts-ignore\n apps: null,\n SDK_VERSION: version,\n INTERNAL: {\n registerComponent,\n removeApp,\n components,\n useAsService\n }\n };\n\n // Inject a circular default export to allow Babel users who were previously\n // using:\n //\n // import firebase from 'firebase';\n // which becomes: var firebase = require('firebase').default;\n //\n // instead of\n //\n // import * as firebase from 'firebase';\n // which becomes: var firebase = require('firebase');\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n (namespace as any)['default'] = namespace;\n\n // firebase.apps is a read-only getter.\n Object.defineProperty(namespace, 'apps', {\n get: getApps\n });\n\n /**\n * Called by App.delete() - but before any services associated with the App\n * are deleted.\n */\n function removeApp(name: string): void {\n delete apps[name];\n }\n\n /**\n * Get the App object for a given name (or DEFAULT).\n */\n function app(name?: string): FirebaseApp {\n name = name || DEFAULT_ENTRY_NAME;\n if (!contains(apps, name)) {\n throw ERROR_FACTORY.create(AppError.NO_APP, { appName: name });\n }\n return apps[name];\n }\n\n // @ts-ignore\n app['App'] = firebaseAppImpl;\n /**\n * Create a new App instance (name must be unique).\n */\n function initializeApp(\n options: FirebaseOptions,\n config?: FirebaseAppConfig\n ): FirebaseApp;\n function initializeApp(options: FirebaseOptions, name?: string): FirebaseApp;\n function initializeApp(\n options: FirebaseOptions,\n rawConfig = {}\n ): FirebaseApp {\n if (typeof rawConfig !== 'object' || rawConfig === null) {\n const name = rawConfig;\n rawConfig = { name };\n }\n\n const config = rawConfig as FirebaseAppConfig;\n\n if (config.name === undefined) {\n config.name = DEFAULT_ENTRY_NAME;\n }\n\n const { name } = config;\n\n if (typeof name !== 'string' || !name) {\n throw ERROR_FACTORY.create(AppError.BAD_APP_NAME, {\n appName: String(name)\n });\n }\n\n if (contains(apps, name)) {\n throw ERROR_FACTORY.create(AppError.DUPLICATE_APP, { appName: name });\n }\n\n const app = new firebaseAppImpl(\n options,\n config,\n namespace as _FirebaseNamespace\n );\n\n apps[name] = app;\n\n return app;\n }\n\n /*\n * Return an array of all the non-deleted FirebaseApps.\n */\n function getApps(): FirebaseApp[] {\n // Make a copy so caller cannot mutate the apps list.\n return Object.keys(apps).map(name => apps[name]);\n }\n\n function registerComponent(\n component: Component\n ): FirebaseServiceNamespace | null {\n const componentName = component.name;\n if (components.has(componentName)) {\n logger.debug(\n `There were multiple attempts to register component ${componentName}.`\n );\n\n return component.type === ComponentType.PUBLIC\n ? // eslint-disable-next-line @typescript-eslint/no-explicit-any\n (namespace as any)[componentName]\n : null;\n }\n\n components.set(componentName, component);\n\n // create service namespace for public components\n if (component.type === ComponentType.PUBLIC) {\n // The Service namespace is an accessor function ...\n const serviceNamespace = (\n appArg: FirebaseApp = app()\n ): FirebaseService => {\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n if (typeof (appArg as any)[componentName] !== 'function') {\n // Invalid argument.\n // This happens in the following case: firebase.storage('gs:/')\n throw ERROR_FACTORY.create(AppError.INVALID_APP_ARGUMENT, {\n appName: componentName\n });\n }\n\n // Forward service instance lookup to the FirebaseApp.\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n return (appArg as any)[componentName]();\n };\n\n // ... and a container for service-level properties.\n if (component.serviceProps !== undefined) {\n deepExtend(serviceNamespace, component.serviceProps);\n }\n\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n (namespace as any)[componentName] = serviceNamespace;\n\n // Patch the FirebaseAppImpl prototype\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n (firebaseAppImpl.prototype as any)[componentName] =\n // TODO: The eslint disable can be removed and the 'ignoreRestArgs'\n // option added to the no-explicit-any rule when ESlint releases it.\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n function(...args: any) {\n const serviceFxn = this._getService.bind(this, componentName);\n return serviceFxn.apply(\n this,\n component.multipleInstances ? args : []\n );\n };\n }\n\n // add the component to existing app instances\n for (const appName of Object.keys(apps)) {\n (apps[appName] as _FirebaseApp)._addComponent(component);\n }\n\n return component.type === ComponentType.PUBLIC\n ? // eslint-disable-next-line @typescript-eslint/no-explicit-any\n (namespace as any)[componentName]\n : null;\n }\n\n function registerVersion(\n libraryKeyOrName: string,\n version: string,\n variant?: string\n ): void {\n // TODO: We can use this check to whitelist strings when/if we set up\n // a good whitelist system.\n let library = PLATFORM_LOG_STRING[libraryKeyOrName] ?? libraryKeyOrName;\n if (variant) {\n library += `-${variant}`;\n }\n const libraryMismatch = library.match(/\\s|\\//);\n const versionMismatch = version.match(/\\s|\\//);\n if (libraryMismatch || versionMismatch) {\n const warning = [\n `Unable to register library \"${library}\" with version \"${version}\":`\n ];\n if (libraryMismatch) {\n warning.push(\n `library name \"${library}\" contains illegal characters (whitespace or \"/\")`\n );\n }\n if (libraryMismatch && versionMismatch) {\n warning.push('and');\n }\n if (versionMismatch) {\n warning.push(\n `version name \"${version}\" contains illegal characters (whitespace or \"/\")`\n );\n }\n logger.warn(warning.join(' '));\n return;\n }\n registerComponent(\n new Component(\n `${library}-version` as Name,\n () => ({ library, version }),\n ComponentType.VERSION\n )\n );\n }\n\n function onLog(logCallback: LogCallback | null, options?: LogOptions): void {\n if (logCallback !== null && typeof logCallback !== 'function') {\n throw ERROR_FACTORY.create(AppError.INVALID_LOG_ARGUMENT, {\n appName: name\n });\n }\n setUserLogHandler(logCallback, options);\n }\n\n // Map the requested service to a registered service name\n // (used to map auth to serverAuth service when needed).\n function useAsService(app: FirebaseApp, name: string): string | null {\n if (name === 'serverAuth') {\n return null;\n }\n\n const useService = name;\n\n return useService;\n }\n\n return namespace;\n}\n","/**\n * @license\n * Copyright 2019 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport {\n ComponentContainer,\n ComponentType,\n Provider,\n Name\n} from '@firebase/component';\n\nexport class PlatformLoggerService {\n constructor(private readonly container: ComponentContainer) {}\n // In initial implementation, this will be called by installations on\n // auth token refresh, and installations will send this string.\n getPlatformInfoString(): string {\n const providers = this.container.getProviders();\n // Loop through providers and get library/version pairs from any that are\n // version components.\n return providers\n .map(provider => {\n if (isVersionServiceProvider(provider)) {\n const service = provider.getImmediate();\n return `${service.library}/${service.version}`;\n } else {\n return null;\n }\n })\n .filter(logString => logString)\n .join(' ');\n }\n}\n/**\n *\n * @param provider check if this provider provides a VersionService\n *\n * NOTE: Using Provider<'app-version'> is a hack to indicate that the provider\n * provides VersionService. The provider is not necessarily a 'app-version'\n * provider.\n */\nfunction isVersionServiceProvider(\n provider: Provider\n): provider is Provider<'app-version'> {\n const component = provider.getComponent();\n return component?.type === ComponentType.VERSION;\n}\n","/**\n * @license\n * Copyright 2019 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport firebase from '@firebase/app';\nimport '@firebase/installations';\nimport { _FirebaseNamespace } from '@firebase/app-types/private';\nimport { RemoteConfig as RemoteConfigType } from '@firebase/remote-config-types';\nimport { CachingClient } from './src/client/caching_client';\nimport { RestClient } from './src/client/rest_client';\nimport { RemoteConfig } from './src/remote_config';\nimport { Storage } from './src/storage/storage';\nimport { StorageCache } from './src/storage/storage_cache';\nimport { ERROR_FACTORY, ErrorCode } from './src/errors';\nimport { RetryingClient } from './src/client/retrying_client';\nimport { Logger, LogLevel as FirebaseLogLevel } from '@firebase/logger';\nimport { name as packageName, version } from './package.json';\nimport {\n Component,\n ComponentType,\n ComponentContainer\n} from '@firebase/component';\n\n// Facilitates debugging by enabling settings changes without rebuilding asset.\n// Note these debug options are not part of a documented, supported API and can change at any time.\n// Consolidates debug options for easier discovery.\n// Uses transient variables on window to avoid lingering state causing panic.\ndeclare global {\n interface Window {\n FIREBASE_REMOTE_CONFIG_URL_BASE: string;\n }\n}\n\nexport function registerRemoteConfig(\n firebaseInstance: _FirebaseNamespace\n): void {\n firebaseInstance.INTERNAL.registerComponent(\n new Component(\n 'remoteConfig',\n remoteConfigFactory,\n ComponentType.PUBLIC\n ).setMultipleInstances(true)\n );\n\n firebaseInstance.registerVersion(packageName, version);\n\n function remoteConfigFactory(\n container: ComponentContainer,\n namespace?: string\n ): RemoteConfig {\n /* Dependencies */\n // getImmediate for FirebaseApp will always succeed\n const app = container.getProvider('app').getImmediate();\n // The following call will always succeed because rc has `import '@firebase/installations'`\n const installations = container.getProvider('installations').getImmediate();\n\n // Guards against the SDK being used in non-browser environments.\n if (typeof window === 'undefined') {\n throw ERROR_FACTORY.create(ErrorCode.REGISTRATION_WINDOW);\n }\n\n // Normalizes optional inputs.\n const { projectId, apiKey, appId } = app.options;\n if (!projectId) {\n throw ERROR_FACTORY.create(ErrorCode.REGISTRATION_PROJECT_ID);\n }\n if (!apiKey) {\n throw ERROR_FACTORY.create(ErrorCode.REGISTRATION_API_KEY);\n }\n if (!appId) {\n throw ERROR_FACTORY.create(ErrorCode.REGISTRATION_APP_ID);\n }\n namespace = namespace || 'firebase';\n\n const storage = new Storage(appId, app.name, namespace);\n const storageCache = new StorageCache(storage);\n\n const logger = new Logger(packageName);\n\n // Sets ERROR as the default log level.\n // See RemoteConfig#setLogLevel for corresponding normalization to ERROR log level.\n logger.logLevel = FirebaseLogLevel.ERROR;\n\n const restClient = new RestClient(\n installations,\n // Uses the JS SDK version, by which the RC package version can be deduced, if necessary.\n firebaseInstance.SDK_VERSION,\n namespace,\n projectId,\n apiKey,\n appId\n );\n const retryingClient = new RetryingClient(restClient, storage);\n const cachingClient = new CachingClient(\n retryingClient,\n storage,\n storageCache,\n logger\n );\n\n const remoteConfigInstance = new RemoteConfig(\n app,\n cachingClient,\n storageCache,\n storage,\n logger\n );\n\n // Starts warming cache.\n // eslint-disable-next-line @typescript-eslint/no-floating-promises\n remoteConfigInstance.ensureInitialized();\n\n return remoteConfigInstance;\n }\n}\n\nregisterRemoteConfig(firebase as _FirebaseNamespace);\n\ndeclare module '@firebase/app-types' {\n interface FirebaseNamespace {\n remoteConfig?: {\n (app?: FirebaseApp): RemoteConfigType;\n };\n }\n interface FirebaseApp {\n remoteConfig(): RemoteConfigType;\n }\n}\n","/**\n * @license\n * Copyright 2019 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { FirebaseNamespace } from '@firebase/app-types';\nimport { _FirebaseNamespace } from '@firebase/app-types/private';\nimport { Component, ComponentType } from '@firebase/component';\nimport { PlatformLoggerService } from './platformLoggerService';\nimport { name, version } from '../package.json';\n\nexport function registerCoreComponents(\n firebase: FirebaseNamespace,\n variant?: string\n): void {\n (firebase as _FirebaseNamespace).INTERNAL.registerComponent(\n new Component(\n 'platform-logger',\n container => new PlatformLoggerService(container),\n ComponentType.PRIVATE\n )\n );\n // Register `app` package.\n firebase.registerVersion(name, version, variant);\n // Register platform SDK identifier (no version).\n firebase.registerVersion('fire-js', '');\n}\n","var now = require('performance-now')\n , root = typeof window === 'undefined' ? global : window\n , vendors = ['moz', 'webkit']\n , suffix = 'AnimationFrame'\n , raf = root['request' + suffix]\n , caf = root['cancel' + suffix] || root['cancelRequest' + suffix]\n\nfor(var i = 0; !raf && i < vendors.length; i++) {\n raf = root[vendors[i] + 'Request' + suffix]\n caf = root[vendors[i] + 'Cancel' + suffix]\n || root[vendors[i] + 'CancelRequest' + suffix]\n}\n\n// Some versions of FF have rAF but not cAF\nif(!raf || !caf) {\n var last = 0\n , id = 0\n , queue = []\n , frameDuration = 1000 / 60\n\n raf = function(callback) {\n if(queue.length === 0) {\n var _now = now()\n , next = Math.max(0, frameDuration - (_now - last))\n last = next + _now\n setTimeout(function() {\n var cp = queue.slice(0)\n // Clear queue here to prevent\n // callbacks from appending listeners\n // to the current frame's queue\n queue.length = 0\n for(var i = 0; i < cp.length; i++) {\n if(!cp[i].cancelled) {\n try{\n cp[i].callback(last)\n } catch(e) {\n setTimeout(function() { throw e }, 0)\n }\n }\n }\n }, Math.round(next))\n }\n queue.push({\n handle: ++id,\n callback: callback,\n cancelled: false\n })\n return id\n }\n\n caf = function(handle) {\n for(var i = 0; i < queue.length; i++) {\n if(queue[i].handle === handle) {\n queue[i].cancelled = true\n }\n }\n }\n}\n\nmodule.exports = function(fn) {\n // Wrap in a new function to prevent\n // `cancel` potentially being assigned\n // to the native rAF function\n return raf.call(root, fn)\n}\nmodule.exports.cancel = function() {\n caf.apply(root, arguments)\n}\nmodule.exports.polyfill = function(object) {\n if (!object) {\n object = root;\n }\n object.requestAnimationFrame = raf\n object.cancelAnimationFrame = caf\n}\n","/**\n * 需要从轴配置中提取出来作为 meta 的属性 key 列表\n */\nexport const AXIS_META_CONFIG_KEYS = [\n 'type',\n 'alias',\n 'tickCount',\n 'tickInterval',\n 'min',\n 'max',\n 'nice',\n 'minLimit',\n 'maxLimit',\n // 坐标轴的范围\n 'range',\n 'tickMethod',\n // type: 'log' 的底\n 'base',\n // type: 'exp' 的指数\n 'exponent',\n // time 类型的格式化\n 'mask',\n // 是否同步\n 'sync',\n];\n","import _extends from \"babel-runtime/helpers/extends\";\nfunction omit(obj, fields) {\n var shallowCopy = _extends({}, obj);\n for (var i = 0; i < fields.length; i++) {\n var key = fields[i];\n delete shallowCopy[key];\n }\n return shallowCopy;\n}\n\nexport default omit;","import objectWithoutPropertiesLoose from \"./objectWithoutPropertiesLoose.js\";\nexport default function _objectWithoutProperties(source, excluded) {\n if (source == null) return {};\n var target = objectWithoutPropertiesLoose(source, excluded);\n var key, i;\n if (Object.getOwnPropertySymbols) {\n var sourceSymbolKeys = Object.getOwnPropertySymbols(source);\n for (i = 0; i < sourceSymbolKeys.length; i++) {\n key = sourceSymbolKeys[i];\n if (excluded.indexOf(key) >= 0) continue;\n if (!Object.prototype.propertyIsEnumerable.call(source, key)) continue;\n target[key] = source[key];\n }\n }\n return target;\n}","function _interopRequireDefault(obj) {\n return obj && obj.__esModule ? obj : {\n \"default\": obj\n };\n}\nmodule.exports = _interopRequireDefault, module.exports.__esModule = true, module.exports[\"default\"] = module.exports;","/*\nHTML escaping is the same as React's\n(on purpose.) Therefore, it has the following Copyright and Licensing:\n\nCopyright 2013-2014, Facebook, Inc.\nAll rights reserved.\n\nThis source code is licensed under the BSD-style license found in the LICENSE\nfile in the root directory of React's source tree.\n*/\nimport * as React from 'react';\nimport IntlMessageFormat from 'intl-messageformat';\nimport memoizeIntlConstructor from 'intl-format-cache';\nimport { invariant } from '@formatjs/intl-utils';\nconst ESCAPED_CHARS = {\n 38: '&',\n 62: '>',\n 60: '<',\n 34: '"',\n 39: ''',\n};\nconst UNSAFE_CHARS_REGEX = /[&><\"']/g;\nexport function escape(str) {\n return ('' + str).replace(UNSAFE_CHARS_REGEX, match => ESCAPED_CHARS[match.charCodeAt(0)]);\n}\nexport function filterProps(props, whitelist, defaults = {}) {\n return whitelist.reduce((filtered, name) => {\n if (name in props) {\n filtered[name] = props[name];\n }\n else if (name in defaults) {\n filtered[name] = defaults[name];\n }\n return filtered;\n }, {});\n}\nexport function invariantIntlContext(intl) {\n invariant(intl, '[React Intl] Could not find required `intl` object. ' +\n ' needs to exist in the component ancestry.');\n}\nexport function createError(message, exception) {\n const eMsg = exception ? `\\n${exception.stack}` : '';\n return `[React Intl] ${message}${eMsg}`;\n}\nexport function defaultErrorHandler(error) {\n if (process.env.NODE_ENV !== 'production') {\n console.error(error);\n }\n}\nexport const DEFAULT_INTL_CONFIG = {\n formats: {},\n messages: {},\n timeZone: undefined,\n textComponent: React.Fragment,\n defaultLocale: 'en',\n defaultFormats: {},\n onError: defaultErrorHandler,\n};\nexport function createIntlCache() {\n return {\n dateTime: {},\n number: {},\n message: {},\n relativeTime: {},\n pluralRules: {},\n list: {},\n displayNames: {},\n };\n}\n/**\n * Create intl formatters and populate cache\n * @param cache explicit cache to prevent leaking memory\n */\nexport function createFormatters(cache = createIntlCache()) {\n const RelativeTimeFormat = Intl.RelativeTimeFormat;\n const ListFormat = Intl.ListFormat;\n const DisplayNames = Intl.DisplayNames;\n return {\n getDateTimeFormat: memoizeIntlConstructor(Intl.DateTimeFormat, cache.dateTime),\n getNumberFormat: memoizeIntlConstructor(Intl.NumberFormat, cache.number),\n getMessageFormat: memoizeIntlConstructor(IntlMessageFormat, cache.message),\n getRelativeTimeFormat: memoizeIntlConstructor(RelativeTimeFormat, cache.relativeTime),\n getPluralRules: memoizeIntlConstructor(Intl.PluralRules, cache.pluralRules),\n getListFormat: memoizeIntlConstructor(ListFormat, cache.list),\n getDisplayNames: memoizeIntlConstructor(DisplayNames, cache.displayNames),\n };\n}\nexport function getNamedFormat(formats, type, name, onError) {\n const formatType = formats && formats[type];\n let format;\n if (formatType) {\n format = formatType[name];\n }\n if (format) {\n return format;\n }\n onError(createError(`No ${type} format named: ${name}`));\n}\n","import * as React from 'react';\nvar isValidElement = React.isValidElement;\nexport { isValidElement };\nexport function replaceElement(element, replacement, props) {\n if (!isValidElement(element)) return replacement;\n return /*#__PURE__*/React.cloneElement(element, typeof props === 'function' ? props() : props);\n}\nexport function cloneElement(element, props) {\n return replaceElement(element, element, props);\n}","export default function _classCallCheck(instance, Constructor) {\n if (!(instance instanceof Constructor)) {\n throw new TypeError(\"Cannot call a class as a function\");\n }\n}","var _typeof = require(\"./typeof.js\")[\"default\"];\nfunction _getRequireWildcardCache(nodeInterop) {\n if (typeof WeakMap !== \"function\") return null;\n var cacheBabelInterop = new WeakMap();\n var cacheNodeInterop = new WeakMap();\n return (_getRequireWildcardCache = function _getRequireWildcardCache(nodeInterop) {\n return nodeInterop ? cacheNodeInterop : cacheBabelInterop;\n })(nodeInterop);\n}\nfunction _interopRequireWildcard(obj, nodeInterop) {\n if (!nodeInterop && obj && obj.__esModule) {\n return obj;\n }\n if (obj === null || _typeof(obj) !== \"object\" && typeof obj !== \"function\") {\n return {\n \"default\": obj\n };\n }\n var cache = _getRequireWildcardCache(nodeInterop);\n if (cache && cache.has(obj)) {\n return cache.get(obj);\n }\n var newObj = {};\n var hasPropertyDescriptor = Object.defineProperty && Object.getOwnPropertyDescriptor;\n for (var key in obj) {\n if (key !== \"default\" && Object.prototype.hasOwnProperty.call(obj, key)) {\n var desc = hasPropertyDescriptor ? Object.getOwnPropertyDescriptor(obj, key) : null;\n if (desc && (desc.get || desc.set)) {\n Object.defineProperty(newObj, key, desc);\n } else {\n newObj[key] = obj[key];\n }\n }\n }\n newObj[\"default\"] = obj;\n if (cache) {\n cache.set(obj, newObj);\n }\n return newObj;\n}\nmodule.exports = _interopRequireWildcard, module.exports.__esModule = true, module.exports[\"default\"] = module.exports;","import toPropertyKey from \"./toPropertyKey.js\";\nfunction _defineProperties(target, props) {\n for (var i = 0; i < props.length; i++) {\n var descriptor = props[i];\n descriptor.enumerable = descriptor.enumerable || false;\n descriptor.configurable = true;\n if (\"value\" in descriptor) descriptor.writable = true;\n Object.defineProperty(target, toPropertyKey(descriptor.key), descriptor);\n }\n}\nexport default function _createClass(Constructor, protoProps, staticProps) {\n if (protoProps) _defineProperties(Constructor.prototype, protoProps);\n if (staticProps) _defineProperties(Constructor, staticProps);\n Object.defineProperty(Constructor, \"prototype\", {\n writable: false\n });\n return Constructor;\n}","import setPrototypeOf from \"./setPrototypeOf.js\";\nexport default function _inherits(subClass, superClass) {\n if (typeof superClass !== \"function\" && superClass !== null) {\n throw new TypeError(\"Super expression must either be null or a function\");\n }\n subClass.prototype = Object.create(superClass && superClass.prototype, {\n constructor: {\n value: subClass,\n writable: true,\n configurable: true\n }\n });\n Object.defineProperty(subClass, \"prototype\", {\n writable: false\n });\n if (superClass) setPrototypeOf(subClass, superClass);\n}","import _typeof from \"./typeof.js\";\nimport assertThisInitialized from \"./assertThisInitialized.js\";\nexport default function _possibleConstructorReturn(self, call) {\n if (call && (_typeof(call) === \"object\" || typeof call === \"function\")) {\n return call;\n } else if (call !== void 0) {\n throw new TypeError(\"Derived constructors may only return object or undefined\");\n }\n return assertThisInitialized(self);\n}","\"use strict\";\n\nvar _interopRequireWildcard = require(\"@babel/runtime/helpers/interopRequireWildcard\");\n\nvar _interopRequireDefault = require(\"@babel/runtime/helpers/interopRequireDefault\");\n\nObject.defineProperty(exports, \"__esModule\", {\n value: true\n});\nexports.default = void 0;\n\nvar _slicedToArray2 = _interopRequireDefault(require(\"@babel/runtime/helpers/slicedToArray\"));\n\nvar _defineProperty2 = _interopRequireDefault(require(\"@babel/runtime/helpers/defineProperty\"));\n\nvar _objectWithoutProperties2 = _interopRequireDefault(require(\"@babel/runtime/helpers/objectWithoutProperties\"));\n\nvar React = _interopRequireWildcard(require(\"react\"));\n\nvar _classnames = _interopRequireDefault(require(\"classnames\"));\n\nvar _IconBase = _interopRequireDefault(require(\"./IconBase\"));\n\nvar _twoTonePrimaryColor = require(\"./twoTonePrimaryColor\");\n\nvar _utils = require(\"../utils\");\n\n// Initial setting\n// should move it to antd main repo?\n(0, _twoTonePrimaryColor.setTwoToneColor)('#1890ff');\nvar Icon = React.forwardRef(function (props, ref) {\n var className = props.className,\n icon = props.icon,\n spin = props.spin,\n rotate = props.rotate,\n tabIndex = props.tabIndex,\n onClick = props.onClick,\n twoToneColor = props.twoToneColor,\n restProps = (0, _objectWithoutProperties2.default)(props, [\"className\", \"icon\", \"spin\", \"rotate\", \"tabIndex\", \"onClick\", \"twoToneColor\"]);\n var classString = (0, _classnames.default)('anticon', (0, _defineProperty2.default)({}, \"anticon-\".concat(icon.name), Boolean(icon.name)), className);\n var svgClassString = (0, _classnames.default)({\n 'anticon-spin': !!spin || icon.name === 'loading'\n });\n var iconTabIndex = tabIndex;\n\n if (iconTabIndex === undefined && onClick) {\n iconTabIndex = -1;\n }\n\n var svgStyle = rotate ? {\n msTransform: \"rotate(\".concat(rotate, \"deg)\"),\n transform: \"rotate(\".concat(rotate, \"deg)\")\n } : undefined;\n\n var _normalizeTwoToneColo = (0, _utils.normalizeTwoToneColors)(twoToneColor),\n _normalizeTwoToneColo2 = (0, _slicedToArray2.default)(_normalizeTwoToneColo, 2),\n primaryColor = _normalizeTwoToneColo2[0],\n secondaryColor = _normalizeTwoToneColo2[1];\n\n return React.createElement(\"span\", Object.assign({\n role: \"img\",\n \"aria-label\": icon.name\n }, restProps, {\n ref: ref,\n tabIndex: iconTabIndex,\n onClick: onClick,\n className: classString\n }), React.createElement(_IconBase.default, {\n className: svgClassString,\n icon: icon,\n primaryColor: primaryColor,\n secondaryColor: secondaryColor,\n style: svgStyle\n }));\n});\nIcon.displayName = 'AntdIcon';\nIcon.getTwoToneColor = _twoTonePrimaryColor.getTwoToneColor;\nIcon.setTwoToneColor = _twoTonePrimaryColor.setTwoToneColor;\nvar _default = Icon;\nexports.default = _default;","export default function _typeof(o) {\n \"@babel/helpers - typeof\";\n\n return _typeof = \"function\" == typeof Symbol && \"symbol\" == typeof Symbol.iterator ? function (o) {\n return typeof o;\n } : function (o) {\n return o && \"function\" == typeof Symbol && o.constructor === Symbol && o !== Symbol.prototype ? \"symbol\" : typeof o;\n }, _typeof(o);\n}","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport firebase from '@firebase/app';\nimport '@firebase/installations';\nimport {\n _FirebaseNamespace,\n FirebaseService\n} from '@firebase/app-types/private';\nimport { FirebaseMessaging } from '@firebase/messaging-types';\nimport {\n Component,\n ComponentType,\n ComponentContainer\n} from '@firebase/component';\nimport { extractAppConfig } from './helpers/extract-app-config';\nimport { FirebaseInternalDependencies } from './interfaces/internal-dependencies';\nimport { ERROR_FACTORY, ErrorCode } from './util/errors';\nimport { WindowController } from './controllers/window-controller';\nimport { SwController } from './controllers/sw-controller';\n\nconst MESSAGING_NAME = 'messaging';\nfunction factoryMethod(\n container: ComponentContainer\n): FirebaseService & FirebaseMessaging {\n // Dependencies.\n const app = container.getProvider('app').getImmediate();\n const appConfig = extractAppConfig(app);\n const installations = container.getProvider('installations').getImmediate();\n const analyticsProvider = container.getProvider('analytics-internal');\n\n const firebaseDependencies: FirebaseInternalDependencies = {\n app,\n appConfig,\n installations,\n analyticsProvider\n };\n\n if (!isSupported()) {\n throw ERROR_FACTORY.create(ErrorCode.UNSUPPORTED_BROWSER);\n }\n\n if (self && 'ServiceWorkerGlobalScope' in self) {\n // Running in ServiceWorker context\n return new SwController(firebaseDependencies);\n } else {\n // Assume we are in the window context.\n return new WindowController(firebaseDependencies);\n }\n}\n\nconst NAMESPACE_EXPORTS = {\n isSupported\n};\n\n(firebase as _FirebaseNamespace).INTERNAL.registerComponent(\n new Component(\n MESSAGING_NAME,\n factoryMethod,\n ComponentType.PUBLIC\n ).setServiceProps(NAMESPACE_EXPORTS)\n);\n\n/**\n * Define extension behavior of `registerMessaging`\n */\ndeclare module '@firebase/app-types' {\n interface FirebaseNamespace {\n messaging: {\n (app?: FirebaseApp): FirebaseMessaging;\n isSupported(): boolean;\n };\n }\n interface FirebaseApp {\n messaging(): FirebaseMessaging;\n }\n}\n\nfunction isSupported(): boolean {\n if (self && 'ServiceWorkerGlobalScope' in self) {\n // Running in ServiceWorker context\n return isSWControllerSupported();\n } else {\n // Assume we are in the window context.\n return isWindowControllerSupported();\n }\n}\n\n/**\n * Checks to see if the required APIs exist.\n */\nfunction isWindowControllerSupported(): boolean {\n return (\n 'indexedDB' in window &&\n indexedDB !== null &&\n navigator.cookieEnabled &&\n 'serviceWorker' in navigator &&\n 'PushManager' in window &&\n 'Notification' in window &&\n 'fetch' in window &&\n ServiceWorkerRegistration.prototype.hasOwnProperty('showNotification') &&\n PushSubscription.prototype.hasOwnProperty('getKey')\n );\n}\n\n/**\n * Checks to see if the required APIs exist within SW Context.\n */\nfunction isSWControllerSupported(): boolean {\n return (\n 'indexedDB' in self &&\n indexedDB !== null &&\n 'PushManager' in self &&\n 'Notification' in self &&\n ServiceWorkerRegistration.prototype.hasOwnProperty('showNotification') &&\n PushSubscription.prototype.hasOwnProperty('getKey')\n );\n}\n","\nexport default function mask(value, precision = 2, decimalSeparator = '.', thousandSeparator = ',', allowNegative = false, prefix = '', suffix = ''){\n // provide some default values and arg validation.\n if (precision < 0) { precision = 0; } // precision cannot be negative\n if (precision > 20) { precision = 20; } // precision cannot be greater than 20\n \n if (value === null || value===undefined) {\n return {\n value: 0,\n maskedValue: ''\n };\n }\n \n value = String(value); //if the given value is a Number, let's convert into String to manipulate that\n\n if (value.length == 0) {\n return {\n value: 0,\n maskedValue: ''\n };\n }\n\n\n // extract digits. if no digits, fill in a zero.\n let digits = value.match(/\\d/g) || ['0'];\n \n let numberIsNegative = false;\n if (allowNegative) {\n let negativeSignCount = (value.match(/-/g) || []).length;\n // number will be negative if we have an odd number of \"-\"\n // ideally, we should only ever have 0, 1 or 2 (positive number, making a number negative\n // and making a negative number positive, respectively)\n numberIsNegative = negativeSignCount % 2 === 1;\n \n // if every digit in the array is '0', then the number should never be negative\n let allDigitsAreZero = true;\n for (let idx=0; idx < digits.length; idx += 1) {\n if(digits[idx] !== '0') {\n allDigitsAreZero = false;\n break;\n }\n }\n if (allDigitsAreZero) {\n numberIsNegative = false;\n }\n }\n\n // zero-pad a input\n while (digits.length <= precision) { digits.unshift('0'); }\n\n if (precision > 0) {\n // add the decimal separator\n digits.splice(digits.length - precision, 0, \".\");\n }\n\n // clean up extraneous digits like leading zeros.\n digits = Number(digits.join('')).toFixed(precision).split('');\n let raw = Number(digits.join(''));\n\n let decimalpos = digits.length - precision - 1; // -1 needed to position the decimal separator before the digits.\n if (precision > 0) {\n // set the final decimal separator\n digits[decimalpos] = decimalSeparator;\n } else {\n // when precision is 0, there is no decimal separator.\n decimalpos = digits.length;\n }\n\n // add in any thousand separators\n for (let x=decimalpos - 3; x > 0; x = x - 3) {\n digits.splice(x, 0, thousandSeparator);\n }\n\n // if we have a prefix or suffix, add them in.\n if (prefix.length > 0) { digits.unshift(prefix); }\n if (suffix.length > 0) { digits.push(suffix); }\n\n // if the number is negative, insert a \"-\" to\n // the front of the array and negate the raw value\n if (allowNegative && numberIsNegative) {\n digits.unshift('-');\n raw = -raw;\n }\n\n return {\n value: raw,\n maskedValue: digits.join('').trim()\n };\n}\n","Object.assign = Object.assign ||\n function(target) {\n for (var i = 1; i < arguments.length; i++) {\n var source = arguments[i];\n for (var key in source) {\n if (Object.prototype.hasOwnProperty.call(source, key)) {\n target[key] = source[key];\n }\n }\n }\n return target;\n };\n","import parse from './parse'\nimport stringify from './stringify'\n\nexport default {\n parse,\n stringify,\n}\n",null,null,null,null,null,null,null,null,"/**\n * Checks if `value` is classified as an `Array` object.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is an array, else `false`.\n * @example\n *\n * _.isArray([1, 2, 3]);\n * // => true\n *\n * _.isArray(document.body.children);\n * // => false\n *\n * _.isArray('abc');\n * // => false\n *\n * _.isArray(_.noop);\n * // => false\n */\nvar isArray = Array.isArray;\n\nmodule.exports = isArray;\n","export default function _extends() {\n _extends = Object.assign ? 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A(e,t,r,n){if(null!==r){var a=Object.keys(r),o=Object.values(r);a.forEach((function(r,a){if(n)return e.push([r,o[a]]);var i=e.findIndex((function(e){return e[0]===r}));if(-1===i){var u=[r];u[t]=o[a],e.push(u)}else e[i][t]=o[a]}))}}function D(e,t){return 0===t.length?e:e.map((function(e){var r=t.findIndex((function(t){return t[0]===e[2]}));if(-1===r)return e;var n=t[r];return n[1]&&(e[4]=n[1]),n[3]&&(e[5]=n[3]),n[2]&&(e[6]=n[2]),e}))}var P=function e(t,r,n,a,i,u,s,l,f,d,p,h,y,m){c(this,e),this.filterRegions=function(e,t){if(\"string\"==typeof e){var r=e;return t.filter((function(e){return e.regions.some((function(e){return e===r}))}))}return t.filter((function(t){return e.map((function(e){return t.regions.some((function(t){return t===e}))})).some((function(e){return e}))}))},this.sortTerritories=function(e,t){var r=[].concat(o(e),o(t));return r.sort((function(e,t){return e.namet.name?1:0})),r},this.getFilteredCountryList=function(e,t,r){return 0===e.length?t:r?e.map((function(e){var r=t.find((function(t){return t.iso2===e}));if(r)return r})).filter((function(e){return e})):t.filter((function(t){return e.some((function(e){return e===t.iso2}))}))},this.localizeCountries=function(e,t){for(var r=0;rt.dialCode.length)return r;if(r.dialCode.length===t.dialCode.length&&r.priority=\"0\"&&e.indexOf(0)<=\"9\"?n.find((function(t){return t.dialCode==+e})):n.find((function(t){return t.iso2==e})))&&t.dialCode&&r.setState({selectedCountry:t,formattedNumber:r.props.disableCountryCode?\"\":r.formatNumber(t.dialCode,t)})},r.scrollTo=function(e,t){if(e){var n=r.dropdownRef;if(n&&document.body){var a=n.offsetHeight,o=n.getBoundingClientRect().top+document.body.scrollTop,i=o+a,u=e,c=u.getBoundingClientRect(),s=u.offsetHeight,l=c.top+document.body.scrollTop,f=l+s,d=l-o+n.scrollTop,p=a/2-s/2;if(r.props.enableSearch?li){t&&(d+=p);var h=a-s;n.scrollTop=d-h}}}},r.scrollToTop=function(){var e=r.dropdownRef;e&&document.body&&(e.scrollTop=0)},r.formatNumber=function(e,t){if(!t)return e;var n,o=t.format,c=r.props,s=c.disableCountryCode,l=c.enableAreaCodeStretch,f=c.enableLongNumbers,d=c.autoFormat;if(s?((n=o.split(\" \")).shift(),n=n.join(\" \")):l&&t.isAreaCode?((n=o.split(\" \"))[1]=n[1].replace(/\\.+/,\"\".padEnd(t.areaCodeLength,\".\")),n=n.join(\" \")):n=o,!e||0===e.length)return s?\"\":r.props.prefix;if(e&&e.length<2||!n||!d)return s?e:r.props.prefix+e;var p,h=w()(n,(function(e,t){if(0===e.remainingText.length)return e;if(\".\"!==t)return{formattedText:e.formattedText+t,remainingText:e.remainingText};var r,n=i(r=e.remainingText)||a(r)||u(),o=n[0],c=n.slice(1);return{formattedText:e.formattedText+o,remainingText:c}}),{formattedText:\"\",remainingText:e.split(\"\")});return(p=f?h.formattedText+h.remainingText.join(\"\"):h.formattedText).includes(\"(\")&&!p.includes(\")\")&&(p+=\")\"),p},r.cursorToEnd=function(){var e=r.numberInputRef;e.focus();var t=e.value.length;\")\"===e.value.charAt(t-1)&&(t-=1),e.setSelectionRange(t,t)},r.getElement=function(e){return r[\"flag_no_\".concat(e)]},r.getCountryData=function(){return r.state.selectedCountry?{name:r.state.selectedCountry.name||\"\",dialCode:r.state.selectedCountry.dialCode||\"\",countryCode:r.state.selectedCountry.iso2||\"\",format:r.state.selectedCountry.format||\"\"}:{}},r.handleFlagDropdownClick=function(e){if(e.preventDefault(),r.state.showDropdown||!r.props.disabled){var t=r.state,n=t.preferredCountries,a=t.selectedCountry,o=n.concat(r.state.onlyCountries).findIndex((function(e){return e.dialCode===a.dialCode&&e.iso2===a.iso2}));r.setState({showDropdown:!r.state.showDropdown,highlightCountryIndex:o},(function(){r.state.showDropdown&&r.scrollTo(r.getElement(r.state.highlightCountryIndex))}))}},r.handleInput=function(e){var t=e.target.value,n=r.props.prefix,a=r.props.disableCountryCode?\"\":n,o=r.state.selectedCountry,i=r.state.freezeSelection;if(!r.props.countryCodeEditable){var u=n+(o.hasAreaCodes?r.state.onlyCountries.find((function(e){return e.iso2===o.iso2&&e.mainCode})).dialCode:o.dialCode);if(t.slice(0,u.length)!==u)return}if(t===n)return r.setState({formattedNumber:\"\"});if((!(t.replace(/\\D/g,\"\").length>15)||r.state.enableLongNumbers)&&t!==r.state.formattedNumber){e.preventDefault?e.preventDefault():e.returnValue=!1;var c=r.props,s=c.country,l=c.onChange,f=r.state,d=f.onlyCountries,p=f.selectedCountry,h=f.hiddenAreaCodes;if(l&&e.persist(),t.length>0){var y=t.replace(/\\D/g,\"\");(!r.state.freezeSelection||p.dialCode.length>y.length)&&(o=r.guessSelectedCountry(y.substring(0,6),s,d,h)||p,i=!1),a=r.formatNumber(y,o),o=o.dialCode?o:p}var m=e.target.selectionStart,g=r.state.formattedNumber,b=a.length-g.length;r.setState({formattedNumber:a,freezeSelection:i,selectedCountry:o},(function(){b>0&&(m-=b),\")\"==a.charAt(a.length-1)?r.numberInputRef.setSelectionRange(a.length-1,a.length-1):m>0&&g.length>=a.length&&r.numberInputRef.setSelectionRange(m,m),l&&l(a.replace(/[^0-9]+/g,\"\"),r.getCountryData(),e,a)}))}},r.handleInputClick=function(e){r.setState({showDropdown:!1}),r.props.onClick&&r.props.onClick(e,r.getCountryData())},r.handleDoubleClick=function(e){var t=e.target.value.length;e.target.setSelectionRange(0,t)},r.handleFlagItemClick=function(e,t){var n=r.state.selectedCountry,a=r.state.onlyCountries.find((function(t){return t==e}));if(a){var o=r.state.formattedNumber.replace(\" \",\"\").replace(\"(\",\"\").replace(\")\",\"\").replace(\"-\",\"\"),i=o.length>1?o.replace(n.dialCode,a.dialCode):a.dialCode,u=r.formatNumber(i.replace(/\\D/g,\"\"),a);r.setState({showDropdown:!1,selectedCountry:a,freezeSelection:!0,formattedNumber:u},(function(){r.cursorToEnd(),r.props.onChange&&r.props.onChange(u.replace(/[^0-9]+/g,\"\"),r.getCountryData(),t,u)}))}},r.handleInputFocus=function(e){r.numberInputRef&&r.numberInputRef.value===r.props.prefix&&r.state.selectedCountry&&!r.props.disableCountryCode&&r.setState({formattedNumber:r.props.prefix+r.state.selectedCountry.dialCode},(function(){r.props.jumpCursorToEnd&&setTimeout(r.cursorToEnd,0)})),r.setState({placeholder:\"\"}),r.props.onFocus&&r.props.onFocus(e,r.getCountryData()),r.props.jumpCursorToEnd&&setTimeout(r.cursorToEnd,0)},r.handleInputBlur=function(e){e.target.value||r.setState({placeholder:r.props.placeholder}),r.props.onBlur&&r.props.onBlur(e,r.getCountryData())},r.handleInputCopy=function(e){if(r.props.copyNumbersOnly){var t=window.getSelection().toString().replace(/[^0-9]+/g,\"\");e.clipboardData.setData(\"text/plain\",t),e.preventDefault()}},r.getHighlightCountryIndex=function(e){var t=r.state.highlightCountryIndex+e;return t<0||t>=r.state.onlyCountries.length+r.state.preferredCountries.length?t-e:r.props.enableSearch&&t>r.getSearchFilteredCountries().length?0:t},r.searchCountry=function(){var e=r.getProbableCandidate(r.state.queryString)||r.state.onlyCountries[0],t=r.state.onlyCountries.findIndex((function(t){return t==e}))+r.state.preferredCountries.length;r.scrollTo(r.getElement(t),!0),r.setState({queryString:\"\",highlightCountryIndex:t})},r.handleKeydown=function(e){var t=r.props.keys,n=e.target.className;if(n.includes(\"selected-flag\")&&e.which===t.ENTER&&!r.state.showDropdown)return r.handleFlagDropdownClick(e);if(n.includes(\"form-control\")&&(e.which===t.ENTER||e.which===t.ESC))return e.target.blur();if(r.state.showDropdown&&!r.props.disabled&&(!n.includes(\"search-box\")||e.which===t.UP||e.which===t.DOWN||e.which===t.ENTER||e.which===t.ESC&&\"\"===e.target.value)){e.preventDefault?e.preventDefault():e.returnValue=!1;var a=function(e){r.setState({highlightCountryIndex:r.getHighlightCountryIndex(e)},(function(){r.scrollTo(r.getElement(r.state.highlightCountryIndex),!0)}))};switch(e.which){case t.DOWN:a(1);break;case t.UP:a(-1);break;case t.ENTER:r.props.enableSearch?r.handleFlagItemClick(r.getSearchFilteredCountries()[r.state.highlightCountryIndex]||r.getSearchFilteredCountries()[0],e):r.handleFlagItemClick([].concat(o(r.state.preferredCountries),o(r.state.onlyCountries))[r.state.highlightCountryIndex],e);break;case t.ESC:r.setState({showDropdown:!1},r.cursorToEnd);break;default:(e.which>=t.A&&e.which<=t.Z||e.which===t.SPACE)&&r.setState({queryString:r.state.queryString+String.fromCharCode(e.which)},r.state.debouncedQueryStingSearcher)}}},r.handleInputKeyDown=function(e){var t=r.props,n=t.keys,a=t.onEnterKeyPress,o=t.onKeyDown;e.which===n.ENTER&&a&&a(e),o&&o(e)},r.handleClickOutside=function(e){r.dropdownRef&&!r.dropdownContainerRef.contains(e.target)&&r.state.showDropdown&&r.setState({showDropdown:!1})},r.handleSearchChange=function(e){var t=e.currentTarget.value,n=r.state,a=n.preferredCountries,o=n.selectedCountry,i=0;if(\"\"===t&&o){var u=r.state.onlyCountries;i=a.concat(u).findIndex((function(e){return e==o})),setTimeout((function(){return r.scrollTo(r.getElement(i))}),100)}r.setState({searchValue:t,highlightCountryIndex:i})},r.getDropdownCountryName=function(e){return e.localName||e.name},r.getSearchFilteredCountries=function(){var e=r.state,t=e.preferredCountries,n=e.onlyCountries,a=e.searchValue,i=r.props.enableSearch,u=t.concat(n),c=a.trim().toLowerCase();if(i&&c){if(/^\\d+$/.test(c))return u.filter((function(e){var t=e.dialCode;return[\"\".concat(t)].some((function(e){return e.toLowerCase().includes(c)}))}));var s=u.filter((function(e){var t=e.iso2;return[\"\".concat(t)].some((function(e){return e.toLowerCase().includes(c)}))})),l=u.filter((function(e){var t=e.name,r=e.localName;e.iso2;return[\"\".concat(t),\"\".concat(r||\"\")].some((function(e){return e.toLowerCase().includes(c)}))}));return r.scrollToTop(),o(new Set([].concat(s,l)))}return u},r.getCountryDropdownList=function(){var e,t=r.state,a=t.preferredCountries,o=t.highlightCountryIndex,i=t.showDropdown,u=t.searchValue,c=r.props,s=c.disableDropdown,l=c.prefix,f=r.props,d=f.enableSearch,p=f.searchNotFound,h=f.disableSearchIcon,y=f.searchClass,g=f.searchStyle,b=f.searchPlaceholder,v=f.autocompleteSearch,C=r.getSearchFilteredCountries().map((function(e,t){var n=o===t,a=O()({country:!0,preferred:\"us\"===e.iso2||\"gb\"===e.iso2,active:\"us\"===e.iso2,highlight:n}),i=\"flag \".concat(e.iso2);return m.a.createElement(\"li\",Object.assign({ref:function(e){return r[\"flag_no_\".concat(t)]=e},key:\"flag_no_\".concat(t),\"data-flag-key\":\"flag_no_\".concat(t),className:a,\"data-dial-code\":\"1\",tabIndex:s?\"-1\":\"0\",\"data-country-code\":e.iso2,onClick:function(t){return r.handleFlagItemClick(e,t)},role:\"option\"},n?{\"aria-selected\":!0}:{}),m.a.createElement(\"div\",{className:i}),m.a.createElement(\"span\",{className:\"country-name\"},r.getDropdownCountryName(e)),m.a.createElement(\"span\",{className:\"dial-code\"},e.format?r.formatNumber(e.dialCode,e):l+e.dialCode))})),_=m.a.createElement(\"li\",{key:\"dashes\",className:\"divider\"});a.length>0&&(!d||d&&!u.trim())&&C.splice(a.length,0,_);var w=O()((n(e={},r.props.dropdownClass,!0),n(e,\"country-list\",!0),n(e,\"hide\",!i),e));return m.a.createElement(\"ul\",{ref:function(e){return!d&&e&&e.focus(),r.dropdownRef=e},className:w,style:r.props.dropdownStyle,role:\"listbox\",tabIndex:\"0\"},d&&m.a.createElement(\"li\",{className:O()(n({search:!0},y,y))},!h&&m.a.createElement(\"span\",{className:O()(n({\"search-emoji\":!0},\"\".concat(y,\"-emoji\"),y)),role:\"img\",\"aria-label\":\"Magnifying glass\"},\"🔎\"),m.a.createElement(\"input\",{className:O()(n({\"search-box\":!0},\"\".concat(y,\"-box\"),y)),style:g,type:\"search\",placeholder:b,autoFocus:!0,autoComplete:v?\"on\":\"off\",value:u,onChange:r.handleSearchChange})),C.length>0?C:m.a.createElement(\"li\",{className:\"no-entries-message\"},m.a.createElement(\"span\",null,p)))};var s,l=new P(e.enableAreaCodes,e.enableTerritories,e.regions,e.onlyCountries,e.preferredCountries,e.excludeCountries,e.preserveOrder,e.masks,e.priority,e.areaCodes,e.localization,e.prefix,e.defaultMask,e.alwaysDefaultMask),h=l.onlyCountries,y=l.preferredCountries,g=l.hiddenAreaCodes,v=e.value.replace(/\\D/g,\"\")||\"\";s=e.disableInitialCountryGuess?0:v.length>1?r.guessSelectedCountry(v.substring(0,6),e.country,h,g)||0:e.country&&h.find((function(t){return t.iso2==e.country}))||0;var _,S=v.length<2&&s&&!j()(v,s.dialCode)?s.dialCode:\"\";_=\"\"===v&&0===s?\"\":r.formatNumber((e.disableCountryCode?\"\":S)+v,s.name?s:void 0);var x=h.findIndex((function(e){return e==s}));return r.state={showDropdown:e.showDropdown,formattedNumber:_,onlyCountries:h,preferredCountries:y,hiddenAreaCodes:g,selectedCountry:s,highlightCountryIndex:x,queryString:\"\",freezeSelection:!1,debouncedQueryStingSearcher:b()(r.searchCountry,250),searchValue:\"\"},r}var r,l,y;return function(e,t){if(\"function\"!=typeof t&&null!==t)throw new TypeError(\"Super expression must either be null or a function\");e.prototype=Object.create(t&&t.prototype,{constructor:{value:e,writable:!0,configurable:!0}}),t&&h(e,t)}(t,e),r=t,(l=[{key:\"componentDidMount\",value:function(){document.addEventListener&&this.props.enableClickOutside&&document.addEventListener(\"mousedown\",this.handleClickOutside)}},{key:\"componentWillUnmount\",value:function(){document.removeEventListener&&this.props.enableClickOutside&&document.removeEventListener(\"mousedown\",this.handleClickOutside)}},{key:\"UNSAFE_componentWillReceiveProps\",value:function(e){e.country!==this.props.country?this.updateCountry(e.country):e.value!==this.props.value&&this.updateFormattedNumber(e.value)}},{key:\"updateFormattedNumber\",value:function(e){if(null===e)return this.setState({selectedCountry:0,formattedNumber:\"\"});var t=this.state,r=t.onlyCountries,n=t.selectedCountry,a=t.hiddenAreaCodes,o=this.props,i=o.country,u=o.prefix;if(\"\"===e)return this.setState({selectedCountry:n,formattedNumber:\"\"});var c,s,l=e.replace(/\\D/g,\"\");if(n&&j()(e,u+n.dialCode))s=this.formatNumber(l,n),this.setState({formattedNumber:s});else{var f=(c=this.guessSelectedCountry(l.substring(0,6),i,r,a)||n)&&j()(l,u+c.dialCode)?c.dialCode:\"\";s=this.formatNumber((this.props.disableCountryCode?\"\":f)+l,c||void 0),this.setState({selectedCountry:c,formattedNumber:s})}}},{key:\"render\",value:function(){var e,t,r,a,o,i=this,u=this.state,c=u.onlyCountries,s=u.selectedCountry,l=u.showDropdown,f=u.formattedNumber,d=u.hiddenAreaCodes,p=this.props,h=p.disableDropdown,y=p.renderStringAsFlag,g=p.isValid,b=p.defaultErrorMessage;if(\"boolean\"==typeof g)a=g;else{var v=g(f.replace(/\\D/g,\"\"),s,c,d);\"boolean\"==typeof v?!1===(a=v)&&(o=b):(a=!1,o=v)}var C=O()((n(e={},this.props.containerClass,!0),n(e,\"react-tel-input\",!0),e)),_=O()({arrow:!0,up:l}),w=O()((n(t={},this.props.inputClass,!0),n(t,\"form-control\",!0),n(t,\"invalid-number\",!a),n(t,\"open\",l),t)),S=O()({\"selected-flag\":!0,open:l}),j=O()((n(r={},this.props.buttonClass,!0),n(r,\"flag-dropdown\",!0),n(r,\"invalid-number\",!a),n(r,\"open\",l),r)),x=\"flag \".concat(s&&s.iso2);return m.a.createElement(\"div\",{className:C,style:this.props.style||this.props.containerStyle,onKeyDown:this.handleKeydown},o&&m.a.createElement(\"div\",{className:\"invalid-number-message\"},o),m.a.createElement(\"input\",Object.assign({className:w,style:this.props.inputStyle,onChange:this.handleInput,onClick:this.handleInputClick,onDoubleClick:this.handleDoubleClick,onFocus:this.handleInputFocus,onBlur:this.handleInputBlur,onCopy:this.handleInputCopy,value:f,ref:function(e){return i.numberInputRef=e},onKeyDown:this.handleInputKeyDown,placeholder:this.props.placeholder,disabled:this.props.disabled,type:\"tel\"},this.props.inputProps)),m.a.createElement(\"div\",{className:j,style:this.props.buttonStyle,ref:function(e){return i.dropdownContainerRef=e}},y?m.a.createElement(\"div\",{className:S},y):m.a.createElement(\"div\",{onClick:h?void 0:this.handleFlagDropdownClick,className:S,title:s?\"\".concat(s.name,\": + \").concat(s.dialCode):\"\",tabIndex:h?\"-1\":\"0\",role:\"button\",\"aria-haspopup\":\"listbox\",\"aria-expanded\":!!l||void 0},m.a.createElement(\"div\",{className:x},!h&&m.a.createElement(\"div\",{className:_}))),l&&this.getCountryDropdownList()))}}])&&s(r.prototype,l),y&&s(r,y),t}(m.a.Component);F.defaultProps={country:\"\",value:\"\",onlyCountries:[],preferredCountries:[],excludeCountries:[],placeholder:\"1 (702) 123-4567\",searchPlaceholder:\"search\",searchNotFound:\"No entries to show\",flagsImagePath:\"./flags.png\",disabled:!1,containerStyle:{},inputStyle:{},buttonStyle:{},dropdownStyle:{},searchStyle:{},containerClass:\"\",inputClass:\"\",buttonClass:\"\",dropdownClass:\"\",searchClass:\"\",autoFormat:!0,enableAreaCodes:!1,enableTerritories:!1,disableCountryCode:!1,disableDropdown:!1,enableLongNumbers:!1,countryCodeEditable:!0,enableSearch:!1,disableSearchIcon:!1,disableInitialCountryGuess:!1,regions:\"\",inputProps:{},localization:{},masks:null,priority:null,areaCodes:null,preserveOrder:[],defaultMask:\"... ... ... ... ..\",alwaysDefaultMask:!1,prefix:\"+\",copyNumbersOnly:!0,renderStringAsFlag:\"\",autocompleteSearch:!1,jumpCursorToEnd:!0,enableAreaCodeStretch:!1,enableClickOutside:!0,showDropdown:!1,isValid:!0,defaultErrorMessage:\"\",onEnterKeyPress:null,keys:{UP:38,DOWN:40,RIGHT:39,LEFT:37,ENTER:13,ESC:27,PLUS:43,A:65,Z:90,SPACE:32}};t.default=F}]);",null,null,null,null,null,null,null,null,null,"/**\n * Common utilities\n * @module glMatrix\n */\n// Configuration Constants\nexport var EPSILON = 0.000001;\nexport var ARRAY_TYPE = typeof Float32Array !== 'undefined' ? Float32Array : Array;\nexport var RANDOM = Math.random;\n/**\n * Sets the type of array used when creating new vectors and matrices\n *\n * @param {Float32ArrayConstructor | ArrayConstructor} type Array type, such as Float32Array or Array\n */\n\nexport function setMatrixArrayType(type) {\n ARRAY_TYPE = type;\n}\nvar degree = Math.PI / 180;\n/**\n * Convert Degree To Radian\n *\n * @param {Number} a Angle in Degrees\n */\n\nexport function toRadian(a) {\n return a * degree;\n}\n/**\n * Tests whether or not the arguments have approximately the same value, within an absolute\n * or relative tolerance of glMatrix.EPSILON (an absolute tolerance is used for values less\n * than or equal to 1.0, and a relative tolerance is used for larger values)\n *\n * @param {Number} a The first number to test.\n * @param {Number} b The second number to test.\n * @returns {Boolean} True if the numbers are approximately equal, false otherwise.\n */\n\nexport function equals(a, b) {\n return Math.abs(a - b) <= EPSILON * Math.max(1.0, Math.abs(a), Math.abs(b));\n}\nif (!Math.hypot) Math.hypot = function () {\n var y = 0,\n i = arguments.length;\n\n while (i--) {\n y += arguments[i] * arguments[i];\n }\n\n return Math.sqrt(y);\n};","import * as React from 'react';\nimport Empty from '../empty';\nimport { ConfigConsumer } from '.';\n\nvar renderEmpty = function renderEmpty(componentName) {\n return /*#__PURE__*/React.createElement(ConfigConsumer, null, function (_ref) {\n var getPrefixCls = _ref.getPrefixCls;\n var prefix = getPrefixCls('empty');\n\n switch (componentName) {\n case 'Table':\n case 'List':\n return /*#__PURE__*/React.createElement(Empty, {\n image: Empty.PRESENTED_IMAGE_SIMPLE\n });\n\n case 'Select':\n case 'TreeSelect':\n case 'Cascader':\n case 'Transfer':\n case 'Mentions':\n return /*#__PURE__*/React.createElement(Empty, {\n image: Empty.PRESENTED_IMAGE_SIMPLE,\n className: \"\".concat(prefix, \"-small\")\n });\n\n default:\n return /*#__PURE__*/React.createElement(Empty, null);\n }\n });\n};\n\nexport default renderEmpty;","function _extends() { _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; }; return _extends.apply(this, arguments); }\n\nimport * as React from 'react';\nimport defaultRenderEmpty from './renderEmpty';\nexport var ConfigContext = /*#__PURE__*/React.createContext({\n // We provide a default function for Context without provider\n getPrefixCls: function getPrefixCls(suffixCls, customizePrefixCls) {\n if (customizePrefixCls) return customizePrefixCls;\n return suffixCls ? \"ant-\".concat(suffixCls) : 'ant';\n },\n renderEmpty: defaultRenderEmpty\n});\nexport var ConfigConsumer = ConfigContext.Consumer;\nexport function withConfigConsumer(config) {\n return function withConfigConsumerFunc(Component) {\n // Wrap with ConfigConsumer. Since we need compatible with react 15, be care when using ref methods\n var SFC = function SFC(props) {\n return /*#__PURE__*/React.createElement(ConfigConsumer, null, function (configProps) {\n var basicPrefixCls = config.prefixCls;\n var getPrefixCls = configProps.getPrefixCls;\n var customizePrefixCls = props.prefixCls;\n var prefixCls = getPrefixCls(basicPrefixCls, customizePrefixCls);\n return /*#__PURE__*/React.createElement(Component, _extends({}, configProps, props, {\n prefixCls: prefixCls\n }));\n });\n };\n\n var cons = Component.constructor;\n var name = cons && cons.displayName || Component.name || 'Component';\n SFC.displayName = \"withConfigConsumer(\".concat(name, \")\");\n return SFC;\n };\n}","/**\n * @license\n * Lodash \n * Copyright OpenJS Foundation and other contributors \n * Released under MIT license \n * Based on Underscore.js 1.8.3 \n * Copyright Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors\n */\n;(function() {\n\n /** Used as a safe reference for `undefined` in pre-ES5 environments. */\n var undefined;\n\n /** Used as the semantic version number. */\n var VERSION = '4.17.15';\n\n /** Used as the size to enable large array optimizations. */\n var LARGE_ARRAY_SIZE = 200;\n\n /** Error message constants. */\n var CORE_ERROR_TEXT = 'Unsupported core-js use. Try https://npms.io/search?q=ponyfill.',\n FUNC_ERROR_TEXT = 'Expected a function';\n\n /** Used to stand-in for `undefined` hash values. */\n var HASH_UNDEFINED = '__lodash_hash_undefined__';\n\n /** Used as the maximum memoize cache size. */\n var MAX_MEMOIZE_SIZE = 500;\n\n /** Used as the internal argument placeholder. */\n var PLACEHOLDER = '__lodash_placeholder__';\n\n /** Used to compose bitmasks for cloning. */\n var CLONE_DEEP_FLAG = 1,\n CLONE_FLAT_FLAG = 2,\n CLONE_SYMBOLS_FLAG = 4;\n\n /** Used to compose bitmasks for value comparisons. */\n var COMPARE_PARTIAL_FLAG = 1,\n COMPARE_UNORDERED_FLAG = 2;\n\n /** Used to compose bitmasks for function metadata. */\n var WRAP_BIND_FLAG = 1,\n WRAP_BIND_KEY_FLAG = 2,\n WRAP_CURRY_BOUND_FLAG = 4,\n WRAP_CURRY_FLAG = 8,\n WRAP_CURRY_RIGHT_FLAG = 16,\n WRAP_PARTIAL_FLAG = 32,\n WRAP_PARTIAL_RIGHT_FLAG = 64,\n WRAP_ARY_FLAG = 128,\n WRAP_REARG_FLAG = 256,\n WRAP_FLIP_FLAG = 512;\n\n /** Used as default options for `_.truncate`. */\n var DEFAULT_TRUNC_LENGTH = 30,\n DEFAULT_TRUNC_OMISSION = '...';\n\n /** Used to detect hot functions by number of calls within a span of milliseconds. */\n var HOT_COUNT = 800,\n HOT_SPAN = 16;\n\n /** Used to indicate the type of lazy iteratees. */\n var LAZY_FILTER_FLAG = 1,\n LAZY_MAP_FLAG = 2,\n LAZY_WHILE_FLAG = 3;\n\n /** Used as references for various `Number` constants. */\n var INFINITY = 1 / 0,\n MAX_SAFE_INTEGER = 9007199254740991,\n MAX_INTEGER = 1.7976931348623157e+308,\n NAN = 0 / 0;\n\n /** Used as references for the maximum length and index of an array. */\n var MAX_ARRAY_LENGTH = 4294967295,\n MAX_ARRAY_INDEX = MAX_ARRAY_LENGTH - 1,\n HALF_MAX_ARRAY_LENGTH = MAX_ARRAY_LENGTH >>> 1;\n\n /** Used to associate wrap methods with their bit flags. */\n var wrapFlags = [\n ['ary', WRAP_ARY_FLAG],\n ['bind', WRAP_BIND_FLAG],\n ['bindKey', WRAP_BIND_KEY_FLAG],\n ['curry', WRAP_CURRY_FLAG],\n ['curryRight', WRAP_CURRY_RIGHT_FLAG],\n ['flip', WRAP_FLIP_FLAG],\n ['partial', WRAP_PARTIAL_FLAG],\n ['partialRight', WRAP_PARTIAL_RIGHT_FLAG],\n ['rearg', WRAP_REARG_FLAG]\n ];\n\n /** `Object#toString` result references. */\n var argsTag = '[object Arguments]',\n arrayTag = '[object Array]',\n asyncTag = '[object AsyncFunction]',\n boolTag = '[object Boolean]',\n dateTag = '[object Date]',\n domExcTag = '[object DOMException]',\n errorTag = '[object Error]',\n funcTag = '[object Function]',\n genTag = '[object GeneratorFunction]',\n mapTag = '[object Map]',\n numberTag = '[object Number]',\n nullTag = '[object Null]',\n objectTag = '[object Object]',\n promiseTag = '[object Promise]',\n proxyTag = '[object Proxy]',\n regexpTag = '[object RegExp]',\n setTag = '[object Set]',\n stringTag = '[object String]',\n symbolTag = '[object Symbol]',\n undefinedTag = '[object Undefined]',\n weakMapTag = '[object WeakMap]',\n weakSetTag = '[object WeakSet]';\n\n var arrayBufferTag = '[object ArrayBuffer]',\n dataViewTag = '[object DataView]',\n float32Tag = '[object Float32Array]',\n float64Tag = '[object Float64Array]',\n int8Tag = '[object Int8Array]',\n int16Tag = '[object Int16Array]',\n int32Tag = '[object Int32Array]',\n uint8Tag = '[object Uint8Array]',\n uint8ClampedTag = '[object Uint8ClampedArray]',\n uint16Tag = '[object Uint16Array]',\n uint32Tag = '[object Uint32Array]';\n\n /** Used to match empty string literals in compiled template source. */\n var reEmptyStringLeading = /\\b__p \\+= '';/g,\n reEmptyStringMiddle = /\\b(__p \\+=) '' \\+/g,\n reEmptyStringTrailing = /(__e\\(.*?\\)|\\b__t\\)) \\+\\n'';/g;\n\n /** Used to match HTML entities and HTML characters. */\n var reEscapedHtml = /&(?:amp|lt|gt|quot|#39);/g,\n reUnescapedHtml = /[&<>\"']/g,\n reHasEscapedHtml = RegExp(reEscapedHtml.source),\n reHasUnescapedHtml = RegExp(reUnescapedHtml.source);\n\n /** Used to match template delimiters. */\n var reEscape = /<%-([\\s\\S]+?)%>/g,\n reEvaluate = /<%([\\s\\S]+?)%>/g,\n reInterpolate = /<%=([\\s\\S]+?)%>/g;\n\n /** Used to match property names within property paths. */\n var reIsDeepProp = /\\.|\\[(?:[^[\\]]*|([\"'])(?:(?!\\1)[^\\\\]|\\\\.)*?\\1)\\]/,\n reIsPlainProp = /^\\w*$/,\n rePropName = /[^.[\\]]+|\\[(?:(-?\\d+(?:\\.\\d+)?)|([\"'])((?:(?!\\2)[^\\\\]|\\\\.)*?)\\2)\\]|(?=(?:\\.|\\[\\])(?:\\.|\\[\\]|$))/g;\n\n /**\n * Used to match `RegExp`\n * [syntax characters](http://ecma-international.org/ecma-262/7.0/#sec-patterns).\n */\n var reRegExpChar = /[\\\\^$.*+?()[\\]{}|]/g,\n reHasRegExpChar = RegExp(reRegExpChar.source);\n\n /** Used to match leading and trailing whitespace. */\n var reTrim = /^\\s+|\\s+$/g,\n reTrimStart = /^\\s+/,\n reTrimEnd = /\\s+$/;\n\n /** Used to match wrap detail comments. */\n var reWrapComment = /\\{(?:\\n\\/\\* \\[wrapped with .+\\] \\*\\/)?\\n?/,\n reWrapDetails = /\\{\\n\\/\\* \\[wrapped with (.+)\\] \\*/,\n reSplitDetails = /,? & /;\n\n /** Used to match words composed of alphanumeric characters. */\n var reAsciiWord = /[^\\x00-\\x2f\\x3a-\\x40\\x5b-\\x60\\x7b-\\x7f]+/g;\n\n /** Used to match backslashes in property paths. */\n var reEscapeChar = /\\\\(\\\\)?/g;\n\n /**\n * Used to match\n * [ES template delimiters](http://ecma-international.org/ecma-262/7.0/#sec-template-literal-lexical-components).\n */\n var reEsTemplate = /\\$\\{([^\\\\}]*(?:\\\\.[^\\\\}]*)*)\\}/g;\n\n /** Used to match `RegExp` flags from their coerced string values. */\n var reFlags = /\\w*$/;\n\n /** Used to detect bad signed hexadecimal string values. */\n var reIsBadHex = /^[-+]0x[0-9a-f]+$/i;\n\n /** Used to detect binary string values. */\n var reIsBinary = /^0b[01]+$/i;\n\n /** Used to detect host constructors (Safari). */\n var reIsHostCtor = /^\\[object .+?Constructor\\]$/;\n\n /** Used to detect octal string values. */\n var reIsOctal = /^0o[0-7]+$/i;\n\n /** Used to detect unsigned integer values. */\n var reIsUint = /^(?:0|[1-9]\\d*)$/;\n\n /** Used to match Latin Unicode letters (excluding mathematical operators). */\n var reLatin = /[\\xc0-\\xd6\\xd8-\\xf6\\xf8-\\xff\\u0100-\\u017f]/g;\n\n /** Used to ensure capturing order of template delimiters. */\n var reNoMatch = /($^)/;\n\n /** Used to match unescaped characters in compiled string literals. */\n var reUnescapedString = /['\\n\\r\\u2028\\u2029\\\\]/g;\n\n /** Used to compose unicode character classes. */\n var rsAstralRange = '\\\\ud800-\\\\udfff',\n rsComboMarksRange = '\\\\u0300-\\\\u036f',\n reComboHalfMarksRange = '\\\\ufe20-\\\\ufe2f',\n rsComboSymbolsRange = '\\\\u20d0-\\\\u20ff',\n rsComboRange = rsComboMarksRange + reComboHalfMarksRange + rsComboSymbolsRange,\n rsDingbatRange = '\\\\u2700-\\\\u27bf',\n rsLowerRange = 'a-z\\\\xdf-\\\\xf6\\\\xf8-\\\\xff',\n rsMathOpRange = '\\\\xac\\\\xb1\\\\xd7\\\\xf7',\n rsNonCharRange = '\\\\x00-\\\\x2f\\\\x3a-\\\\x40\\\\x5b-\\\\x60\\\\x7b-\\\\xbf',\n rsPunctuationRange = '\\\\u2000-\\\\u206f',\n rsSpaceRange = ' \\\\t\\\\x0b\\\\f\\\\xa0\\\\ufeff\\\\n\\\\r\\\\u2028\\\\u2029\\\\u1680\\\\u180e\\\\u2000\\\\u2001\\\\u2002\\\\u2003\\\\u2004\\\\u2005\\\\u2006\\\\u2007\\\\u2008\\\\u2009\\\\u200a\\\\u202f\\\\u205f\\\\u3000',\n rsUpperRange = 'A-Z\\\\xc0-\\\\xd6\\\\xd8-\\\\xde',\n rsVarRange = '\\\\ufe0e\\\\ufe0f',\n rsBreakRange = rsMathOpRange + rsNonCharRange + rsPunctuationRange + rsSpaceRange;\n\n /** Used to compose unicode capture groups. */\n var rsApos = \"['\\u2019]\",\n rsAstral = '[' + rsAstralRange + ']',\n rsBreak = '[' + rsBreakRange + ']',\n rsCombo = '[' + rsComboRange + ']',\n rsDigits = '\\\\d+',\n rsDingbat = '[' + rsDingbatRange + ']',\n rsLower = '[' + rsLowerRange + ']',\n rsMisc = '[^' + rsAstralRange + rsBreakRange + rsDigits + rsDingbatRange + rsLowerRange + rsUpperRange + ']',\n rsFitz = '\\\\ud83c[\\\\udffb-\\\\udfff]',\n rsModifier = '(?:' + rsCombo + '|' + rsFitz + ')',\n rsNonAstral = '[^' + rsAstralRange + ']',\n rsRegional = '(?:\\\\ud83c[\\\\udde6-\\\\uddff]){2}',\n rsSurrPair = '[\\\\ud800-\\\\udbff][\\\\udc00-\\\\udfff]',\n rsUpper = '[' + rsUpperRange + ']',\n rsZWJ = '\\\\u200d';\n\n /** Used to compose unicode regexes. */\n var rsMiscLower = '(?:' + rsLower + '|' + rsMisc + ')',\n rsMiscUpper = '(?:' + rsUpper + '|' + rsMisc + ')',\n rsOptContrLower = '(?:' + rsApos + '(?:d|ll|m|re|s|t|ve))?',\n rsOptContrUpper = '(?:' + rsApos + '(?:D|LL|M|RE|S|T|VE))?',\n reOptMod = rsModifier + '?',\n rsOptVar = '[' + rsVarRange + ']?',\n rsOptJoin = '(?:' + rsZWJ + '(?:' + [rsNonAstral, rsRegional, rsSurrPair].join('|') + ')' + rsOptVar + reOptMod + ')*',\n rsOrdLower = '\\\\d*(?:1st|2nd|3rd|(?![123])\\\\dth)(?=\\\\b|[A-Z_])',\n rsOrdUpper = '\\\\d*(?:1ST|2ND|3RD|(?![123])\\\\dTH)(?=\\\\b|[a-z_])',\n rsSeq = rsOptVar + reOptMod + rsOptJoin,\n rsEmoji = '(?:' + [rsDingbat, rsRegional, rsSurrPair].join('|') + ')' + rsSeq,\n rsSymbol = '(?:' + [rsNonAstral + rsCombo + '?', rsCombo, rsRegional, rsSurrPair, rsAstral].join('|') + ')';\n\n /** Used to match apostrophes. */\n var reApos = RegExp(rsApos, 'g');\n\n /**\n * Used to match [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks) and\n * [combining diacritical marks for symbols](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks_for_Symbols).\n */\n var reComboMark = RegExp(rsCombo, 'g');\n\n /** Used to match [string symbols](https://mathiasbynens.be/notes/javascript-unicode). */\n var reUnicode = RegExp(rsFitz + '(?=' + rsFitz + ')|' + rsSymbol + rsSeq, 'g');\n\n /** Used to match complex or compound words. */\n var reUnicodeWord = RegExp([\n rsUpper + '?' + rsLower + '+' + rsOptContrLower + '(?=' + [rsBreak, rsUpper, '$'].join('|') + ')',\n rsMiscUpper + '+' + rsOptContrUpper + '(?=' + [rsBreak, rsUpper + rsMiscLower, '$'].join('|') + ')',\n rsUpper + '?' + rsMiscLower + '+' + rsOptContrLower,\n rsUpper + '+' + rsOptContrUpper,\n rsOrdUpper,\n rsOrdLower,\n rsDigits,\n rsEmoji\n ].join('|'), 'g');\n\n /** Used to detect strings with [zero-width joiners or code points from the astral planes](http://eev.ee/blog/2015/09/12/dark-corners-of-unicode/). */\n var reHasUnicode = RegExp('[' + rsZWJ + rsAstralRange + rsComboRange + rsVarRange + ']');\n\n /** Used to detect strings that need a more robust regexp to match words. */\n var reHasUnicodeWord = /[a-z][A-Z]|[A-Z]{2}[a-z]|[0-9][a-zA-Z]|[a-zA-Z][0-9]|[^a-zA-Z0-9 ]/;\n\n /** Used to assign default `context` object properties. */\n var contextProps = [\n 'Array', 'Buffer', 'DataView', 'Date', 'Error', 'Float32Array', 'Float64Array',\n 'Function', 'Int8Array', 'Int16Array', 'Int32Array', 'Map', 'Math', 'Object',\n 'Promise', 'RegExp', 'Set', 'String', 'Symbol', 'TypeError', 'Uint8Array',\n 'Uint8ClampedArray', 'Uint16Array', 'Uint32Array', 'WeakMap',\n '_', 'clearTimeout', 'isFinite', 'parseInt', 'setTimeout'\n ];\n\n /** Used to make template sourceURLs easier to identify. */\n var templateCounter = -1;\n\n /** Used to identify `toStringTag` values of typed arrays. */\n var typedArrayTags = {};\n typedArrayTags[float32Tag] = typedArrayTags[float64Tag] =\n typedArrayTags[int8Tag] = typedArrayTags[int16Tag] =\n typedArrayTags[int32Tag] = typedArrayTags[uint8Tag] =\n typedArrayTags[uint8ClampedTag] = typedArrayTags[uint16Tag] =\n typedArrayTags[uint32Tag] = true;\n typedArrayTags[argsTag] = typedArrayTags[arrayTag] =\n typedArrayTags[arrayBufferTag] = typedArrayTags[boolTag] =\n typedArrayTags[dataViewTag] = typedArrayTags[dateTag] =\n typedArrayTags[errorTag] = typedArrayTags[funcTag] =\n typedArrayTags[mapTag] = typedArrayTags[numberTag] =\n typedArrayTags[objectTag] = typedArrayTags[regexpTag] =\n typedArrayTags[setTag] = typedArrayTags[stringTag] =\n typedArrayTags[weakMapTag] = false;\n\n /** Used to identify `toStringTag` values supported by `_.clone`. */\n var cloneableTags = {};\n cloneableTags[argsTag] = cloneableTags[arrayTag] =\n cloneableTags[arrayBufferTag] = cloneableTags[dataViewTag] =\n cloneableTags[boolTag] = cloneableTags[dateTag] =\n cloneableTags[float32Tag] = cloneableTags[float64Tag] =\n cloneableTags[int8Tag] = cloneableTags[int16Tag] =\n cloneableTags[int32Tag] = cloneableTags[mapTag] =\n cloneableTags[numberTag] = cloneableTags[objectTag] =\n cloneableTags[regexpTag] = cloneableTags[setTag] =\n cloneableTags[stringTag] = cloneableTags[symbolTag] =\n cloneableTags[uint8Tag] = cloneableTags[uint8ClampedTag] =\n cloneableTags[uint16Tag] = cloneableTags[uint32Tag] = true;\n cloneableTags[errorTag] = cloneableTags[funcTag] =\n cloneableTags[weakMapTag] = false;\n\n /** Used to map Latin Unicode letters to basic Latin letters. */\n var deburredLetters = {\n // Latin-1 Supplement block.\n '\\xc0': 'A', '\\xc1': 'A', '\\xc2': 'A', '\\xc3': 'A', '\\xc4': 'A', '\\xc5': 'A',\n '\\xe0': 'a', '\\xe1': 'a', '\\xe2': 'a', '\\xe3': 'a', '\\xe4': 'a', '\\xe5': 'a',\n '\\xc7': 'C', '\\xe7': 'c',\n '\\xd0': 'D', '\\xf0': 'd',\n '\\xc8': 'E', '\\xc9': 'E', '\\xca': 'E', '\\xcb': 'E',\n '\\xe8': 'e', '\\xe9': 'e', '\\xea': 'e', '\\xeb': 'e',\n '\\xcc': 'I', '\\xcd': 'I', '\\xce': 'I', '\\xcf': 'I',\n '\\xec': 'i', '\\xed': 'i', '\\xee': 'i', '\\xef': 'i',\n '\\xd1': 'N', '\\xf1': 'n',\n '\\xd2': 'O', '\\xd3': 'O', '\\xd4': 'O', '\\xd5': 'O', '\\xd6': 'O', '\\xd8': 'O',\n '\\xf2': 'o', '\\xf3': 'o', '\\xf4': 'o', '\\xf5': 'o', '\\xf6': 'o', '\\xf8': 'o',\n '\\xd9': 'U', '\\xda': 'U', '\\xdb': 'U', '\\xdc': 'U',\n '\\xf9': 'u', '\\xfa': 'u', '\\xfb': 'u', '\\xfc': 'u',\n '\\xdd': 'Y', '\\xfd': 'y', '\\xff': 'y',\n '\\xc6': 'Ae', '\\xe6': 'ae',\n '\\xde': 'Th', '\\xfe': 'th',\n '\\xdf': 'ss',\n // Latin Extended-A block.\n '\\u0100': 'A', '\\u0102': 'A', '\\u0104': 'A',\n '\\u0101': 'a', '\\u0103': 'a', '\\u0105': 'a',\n '\\u0106': 'C', '\\u0108': 'C', '\\u010a': 'C', '\\u010c': 'C',\n '\\u0107': 'c', '\\u0109': 'c', '\\u010b': 'c', '\\u010d': 'c',\n '\\u010e': 'D', '\\u0110': 'D', '\\u010f': 'd', '\\u0111': 'd',\n '\\u0112': 'E', '\\u0114': 'E', '\\u0116': 'E', '\\u0118': 'E', '\\u011a': 'E',\n '\\u0113': 'e', '\\u0115': 'e', '\\u0117': 'e', '\\u0119': 'e', '\\u011b': 'e',\n '\\u011c': 'G', '\\u011e': 'G', '\\u0120': 'G', '\\u0122': 'G',\n '\\u011d': 'g', '\\u011f': 'g', '\\u0121': 'g', '\\u0123': 'g',\n '\\u0124': 'H', '\\u0126': 'H', '\\u0125': 'h', '\\u0127': 'h',\n '\\u0128': 'I', '\\u012a': 'I', '\\u012c': 'I', '\\u012e': 'I', '\\u0130': 'I',\n '\\u0129': 'i', '\\u012b': 'i', '\\u012d': 'i', '\\u012f': 'i', '\\u0131': 'i',\n '\\u0134': 'J', '\\u0135': 'j',\n '\\u0136': 'K', '\\u0137': 'k', '\\u0138': 'k',\n '\\u0139': 'L', '\\u013b': 'L', '\\u013d': 'L', '\\u013f': 'L', '\\u0141': 'L',\n '\\u013a': 'l', '\\u013c': 'l', '\\u013e': 'l', '\\u0140': 'l', '\\u0142': 'l',\n '\\u0143': 'N', '\\u0145': 'N', '\\u0147': 'N', '\\u014a': 'N',\n '\\u0144': 'n', '\\u0146': 'n', '\\u0148': 'n', '\\u014b': 'n',\n '\\u014c': 'O', '\\u014e': 'O', '\\u0150': 'O',\n '\\u014d': 'o', '\\u014f': 'o', '\\u0151': 'o',\n '\\u0154': 'R', '\\u0156': 'R', '\\u0158': 'R',\n '\\u0155': 'r', '\\u0157': 'r', '\\u0159': 'r',\n '\\u015a': 'S', '\\u015c': 'S', '\\u015e': 'S', '\\u0160': 'S',\n '\\u015b': 's', '\\u015d': 's', '\\u015f': 's', '\\u0161': 's',\n '\\u0162': 'T', '\\u0164': 'T', '\\u0166': 'T',\n '\\u0163': 't', '\\u0165': 't', '\\u0167': 't',\n '\\u0168': 'U', '\\u016a': 'U', '\\u016c': 'U', '\\u016e': 'U', '\\u0170': 'U', '\\u0172': 'U',\n '\\u0169': 'u', '\\u016b': 'u', '\\u016d': 'u', '\\u016f': 'u', '\\u0171': 'u', '\\u0173': 'u',\n '\\u0174': 'W', '\\u0175': 'w',\n '\\u0176': 'Y', '\\u0177': 'y', '\\u0178': 'Y',\n '\\u0179': 'Z', '\\u017b': 'Z', '\\u017d': 'Z',\n '\\u017a': 'z', '\\u017c': 'z', '\\u017e': 'z',\n '\\u0132': 'IJ', '\\u0133': 'ij',\n '\\u0152': 'Oe', '\\u0153': 'oe',\n '\\u0149': \"'n\", '\\u017f': 's'\n };\n\n /** Used to map characters to HTML entities. */\n var htmlEscapes = {\n '&': '&',\n '<': '<',\n '>': '>',\n '\"': '"',\n \"'\": '''\n };\n\n /** Used to map HTML entities to characters. */\n var htmlUnescapes = {\n '&': '&',\n '<': '<',\n '>': '>',\n '"': '\"',\n ''': \"'\"\n };\n\n /** Used to escape characters for inclusion in compiled string literals. */\n var stringEscapes = {\n '\\\\': '\\\\',\n \"'\": \"'\",\n '\\n': 'n',\n '\\r': 'r',\n '\\u2028': 'u2028',\n '\\u2029': 'u2029'\n };\n\n /** Built-in method references without a dependency on `root`. */\n var freeParseFloat = parseFloat,\n freeParseInt = parseInt;\n\n /** Detect free variable `global` from Node.js. */\n var freeGlobal = typeof global == 'object' && global && global.Object === Object && global;\n\n /** Detect free variable `self`. */\n var freeSelf = typeof self == 'object' && self && self.Object === Object && self;\n\n /** Used as a reference to the global object. */\n var root = freeGlobal || freeSelf || Function('return this')();\n\n /** Detect free variable `exports`. */\n var freeExports = typeof exports == 'object' && exports && !exports.nodeType && exports;\n\n /** Detect free variable `module`. */\n var freeModule = freeExports && typeof module == 'object' && module && !module.nodeType && module;\n\n /** Detect the popular CommonJS extension `module.exports`. */\n var moduleExports = freeModule && freeModule.exports === freeExports;\n\n /** Detect free variable `process` from Node.js. */\n var freeProcess = moduleExports && freeGlobal.process;\n\n /** Used to access faster Node.js helpers. */\n var nodeUtil = (function() {\n try {\n // Use `util.types` for Node.js 10+.\n var types = freeModule && freeModule.require && freeModule.require('util').types;\n\n if (types) {\n return types;\n }\n\n // Legacy `process.binding('util')` for Node.js < 10.\n return freeProcess && freeProcess.binding && freeProcess.binding('util');\n } catch (e) {}\n }());\n\n /* Node.js helper references. */\n var nodeIsArrayBuffer = nodeUtil && nodeUtil.isArrayBuffer,\n nodeIsDate = nodeUtil && nodeUtil.isDate,\n nodeIsMap = nodeUtil && nodeUtil.isMap,\n nodeIsRegExp = nodeUtil && nodeUtil.isRegExp,\n nodeIsSet = nodeUtil && nodeUtil.isSet,\n nodeIsTypedArray = nodeUtil && nodeUtil.isTypedArray;\n\n /*--------------------------------------------------------------------------*/\n\n /**\n * A faster alternative to `Function#apply`, this function invokes `func`\n * with the `this` binding of `thisArg` and the arguments of `args`.\n *\n * @private\n * @param {Function} func The function to invoke.\n * @param {*} thisArg The `this` binding of `func`.\n * @param {Array} args The arguments to invoke `func` with.\n * @returns {*} Returns the result of `func`.\n */\n function apply(func, thisArg, args) {\n switch (args.length) {\n case 0: return func.call(thisArg);\n case 1: return func.call(thisArg, args[0]);\n case 2: return func.call(thisArg, args[0], args[1]);\n case 3: return func.call(thisArg, args[0], args[1], args[2]);\n }\n return func.apply(thisArg, args);\n }\n\n /**\n * A specialized version of `baseAggregator` for arrays.\n *\n * @private\n * @param {Array} [array] The array to iterate over.\n * @param {Function} setter The function to set `accumulator` values.\n * @param {Function} iteratee The iteratee to transform keys.\n * @param {Object} accumulator The initial aggregated object.\n * @returns {Function} Returns `accumulator`.\n */\n function arrayAggregator(array, setter, iteratee, accumulator) {\n var index = -1,\n length = array == null ? 0 : array.length;\n\n while (++index < length) {\n var value = array[index];\n setter(accumulator, value, iteratee(value), array);\n }\n return accumulator;\n }\n\n /**\n * A specialized version of `_.forEach` for arrays without support for\n * iteratee shorthands.\n *\n * @private\n * @param {Array} [array] The array to iterate over.\n * @param {Function} iteratee The function invoked per iteration.\n * @returns {Array} Returns `array`.\n */\n function arrayEach(array, iteratee) {\n var index = -1,\n length = array == null ? 0 : array.length;\n\n while (++index < length) {\n if (iteratee(array[index], index, array) === false) {\n break;\n }\n }\n return array;\n }\n\n /**\n * A specialized version of `_.forEachRight` for arrays without support for\n * iteratee shorthands.\n *\n * @private\n * @param {Array} [array] The array to iterate over.\n * @param {Function} iteratee The function invoked per iteration.\n * @returns {Array} Returns `array`.\n */\n function arrayEachRight(array, iteratee) {\n var length = array == null ? 0 : array.length;\n\n while (length--) {\n if (iteratee(array[length], length, array) === false) {\n break;\n }\n }\n return array;\n }\n\n /**\n * A specialized version of `_.every` for arrays without support for\n * iteratee shorthands.\n *\n * @private\n * @param {Array} [array] The array to iterate over.\n * @param {Function} predicate The function invoked per iteration.\n * @returns {boolean} Returns `true` if all elements pass the predicate check,\n * else `false`.\n */\n function arrayEvery(array, predicate) {\n var index = -1,\n length = array == null ? 0 : array.length;\n\n while (++index < length) {\n if (!predicate(array[index], index, array)) {\n return false;\n }\n }\n return true;\n }\n\n /**\n * A specialized version of `_.filter` for arrays without support for\n * iteratee shorthands.\n *\n * @private\n * @param {Array} [array] The array to iterate over.\n * @param {Function} predicate The function invoked per iteration.\n * @returns {Array} Returns the new filtered array.\n */\n function arrayFilter(array, predicate) {\n var index = -1,\n length = array == null ? 0 : array.length,\n resIndex = 0,\n result = [];\n\n while (++index < length) {\n var value = array[index];\n if (predicate(value, index, array)) {\n result[resIndex++] = value;\n }\n }\n return result;\n }\n\n /**\n * A specialized version of `_.includes` for arrays without support for\n * specifying an index to search from.\n *\n * @private\n * @param {Array} [array] The array to inspect.\n * @param {*} target The value to search for.\n * @returns {boolean} Returns `true` if `target` is found, else `false`.\n */\n function arrayIncludes(array, value) {\n var length = array == null ? 0 : array.length;\n return !!length && baseIndexOf(array, value, 0) > -1;\n }\n\n /**\n * This function is like `arrayIncludes` except that it accepts a comparator.\n *\n * @private\n * @param {Array} [array] The array to inspect.\n * @param {*} target The value to search for.\n * @param {Function} comparator The comparator invoked per element.\n * @returns {boolean} Returns `true` if `target` is found, else `false`.\n */\n function arrayIncludesWith(array, value, comparator) {\n var index = -1,\n length = array == null ? 0 : array.length;\n\n while (++index < length) {\n if (comparator(value, array[index])) {\n return true;\n }\n }\n return false;\n }\n\n /**\n * A specialized version of `_.map` for arrays without support for iteratee\n * shorthands.\n *\n * @private\n * @param {Array} [array] The array to iterate over.\n * @param {Function} iteratee The function invoked per iteration.\n * @returns {Array} Returns the new mapped array.\n */\n function arrayMap(array, iteratee) {\n var index = -1,\n length = array == null ? 0 : array.length,\n result = Array(length);\n\n while (++index < length) {\n result[index] = iteratee(array[index], index, array);\n }\n return result;\n }\n\n /**\n * Appends the elements of `values` to `array`.\n *\n * @private\n * @param {Array} array The array to modify.\n * @param {Array} values The values to append.\n * @returns {Array} Returns `array`.\n */\n function arrayPush(array, values) {\n var index = -1,\n length = values.length,\n offset = array.length;\n\n while (++index < length) {\n array[offset + index] = values[index];\n }\n return array;\n }\n\n /**\n * A specialized version of `_.reduce` for arrays without support for\n * iteratee shorthands.\n *\n * @private\n * @param {Array} [array] The array to iterate over.\n * @param {Function} iteratee The function invoked per iteration.\n * @param {*} [accumulator] The initial value.\n * @param {boolean} [initAccum] Specify using the first element of `array` as\n * the initial value.\n * @returns {*} Returns the accumulated value.\n */\n function arrayReduce(array, iteratee, accumulator, initAccum) {\n var index = -1,\n length = array == null ? 0 : array.length;\n\n if (initAccum && length) {\n accumulator = array[++index];\n }\n while (++index < length) {\n accumulator = iteratee(accumulator, array[index], index, array);\n }\n return accumulator;\n }\n\n /**\n * A specialized version of `_.reduceRight` for arrays without support for\n * iteratee shorthands.\n *\n * @private\n * @param {Array} [array] The array to iterate over.\n * @param {Function} iteratee The function invoked per iteration.\n * @param {*} [accumulator] The initial value.\n * @param {boolean} [initAccum] Specify using the last element of `array` as\n * the initial value.\n * @returns {*} Returns the accumulated value.\n */\n function arrayReduceRight(array, iteratee, accumulator, initAccum) {\n var length = array == null ? 0 : array.length;\n if (initAccum && length) {\n accumulator = array[--length];\n }\n while (length--) {\n accumulator = iteratee(accumulator, array[length], length, array);\n }\n return accumulator;\n }\n\n /**\n * A specialized version of `_.some` for arrays without support for iteratee\n * shorthands.\n *\n * @private\n * @param {Array} [array] The array to iterate over.\n * @param {Function} predicate The function invoked per iteration.\n * @returns {boolean} Returns `true` if any element passes the predicate check,\n * else `false`.\n */\n function arraySome(array, predicate) {\n var index = -1,\n length = array == null ? 0 : array.length;\n\n while (++index < length) {\n if (predicate(array[index], index, array)) {\n return true;\n }\n }\n return false;\n }\n\n /**\n * Gets the size of an ASCII `string`.\n *\n * @private\n * @param {string} string The string inspect.\n * @returns {number} Returns the string size.\n */\n var asciiSize = baseProperty('length');\n\n /**\n * Converts an ASCII `string` to an array.\n *\n * @private\n * @param {string} string The string to convert.\n * @returns {Array} Returns the converted array.\n */\n function asciiToArray(string) {\n return string.split('');\n }\n\n /**\n * Splits an ASCII `string` into an array of its words.\n *\n * @private\n * @param {string} The string to inspect.\n * @returns {Array} Returns the words of `string`.\n */\n function asciiWords(string) {\n return string.match(reAsciiWord) || [];\n }\n\n /**\n * The base implementation of methods like `_.findKey` and `_.findLastKey`,\n * without support for iteratee shorthands, which iterates over `collection`\n * using `eachFunc`.\n *\n * @private\n * @param {Array|Object} collection The collection to inspect.\n * @param {Function} predicate The function invoked per iteration.\n * @param {Function} eachFunc The function to iterate over `collection`.\n * @returns {*} Returns the found element or its key, else `undefined`.\n */\n function baseFindKey(collection, predicate, eachFunc) {\n var result;\n eachFunc(collection, function(value, key, collection) {\n if (predicate(value, key, collection)) {\n result = key;\n return false;\n }\n });\n return result;\n }\n\n /**\n * The base implementation of `_.findIndex` and `_.findLastIndex` without\n * support for iteratee shorthands.\n *\n * @private\n * @param {Array} array The array to inspect.\n * @param {Function} predicate The function invoked per iteration.\n * @param {number} fromIndex The index to search from.\n * @param {boolean} [fromRight] Specify iterating from right to left.\n * @returns {number} Returns the index of the matched value, else `-1`.\n */\n function baseFindIndex(array, predicate, fromIndex, fromRight) {\n var length = array.length,\n index = fromIndex + (fromRight ? 1 : -1);\n\n while ((fromRight ? index-- : ++index < length)) {\n if (predicate(array[index], index, array)) {\n return index;\n }\n }\n return -1;\n }\n\n /**\n * The base implementation of `_.indexOf` without `fromIndex` bounds checks.\n *\n * @private\n * @param {Array} array The array to inspect.\n * @param {*} value The value to search for.\n * @param {number} fromIndex The index to search from.\n * @returns {number} Returns the index of the matched value, else `-1`.\n */\n function baseIndexOf(array, value, fromIndex) {\n return value === value\n ? strictIndexOf(array, value, fromIndex)\n : baseFindIndex(array, baseIsNaN, fromIndex);\n }\n\n /**\n * This function is like `baseIndexOf` except that it accepts a comparator.\n *\n * @private\n * @param {Array} array The array to inspect.\n * @param {*} value The value to search for.\n * @param {number} fromIndex The index to search from.\n * @param {Function} comparator The comparator invoked per element.\n * @returns {number} Returns the index of the matched value, else `-1`.\n */\n function baseIndexOfWith(array, value, fromIndex, comparator) {\n var index = fromIndex - 1,\n length = array.length;\n\n while (++index < length) {\n if (comparator(array[index], value)) {\n return index;\n }\n }\n return -1;\n }\n\n /**\n * The base implementation of `_.isNaN` without support for number objects.\n *\n * @private\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is `NaN`, else `false`.\n */\n function baseIsNaN(value) {\n return value !== value;\n }\n\n /**\n * The base implementation of `_.mean` and `_.meanBy` without support for\n * iteratee shorthands.\n *\n * @private\n * @param {Array} array The array to iterate over.\n * @param {Function} iteratee The function invoked per iteration.\n * @returns {number} Returns the mean.\n */\n function baseMean(array, iteratee) {\n var length = array == null ? 0 : array.length;\n return length ? (baseSum(array, iteratee) / length) : NAN;\n }\n\n /**\n * The base implementation of `_.property` without support for deep paths.\n *\n * @private\n * @param {string} key The key of the property to get.\n * @returns {Function} Returns the new accessor function.\n */\n function baseProperty(key) {\n return function(object) {\n return object == null ? undefined : object[key];\n };\n }\n\n /**\n * The base implementation of `_.propertyOf` without support for deep paths.\n *\n * @private\n * @param {Object} object The object to query.\n * @returns {Function} Returns the new accessor function.\n */\n function basePropertyOf(object) {\n return function(key) {\n return object == null ? undefined : object[key];\n };\n }\n\n /**\n * The base implementation of `_.reduce` and `_.reduceRight`, without support\n * for iteratee shorthands, which iterates over `collection` using `eachFunc`.\n *\n * @private\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} iteratee The function invoked per iteration.\n * @param {*} accumulator The initial value.\n * @param {boolean} initAccum Specify using the first or last element of\n * `collection` as the initial value.\n * @param {Function} eachFunc The function to iterate over `collection`.\n * @returns {*} Returns the accumulated value.\n */\n function baseReduce(collection, iteratee, accumulator, initAccum, eachFunc) {\n eachFunc(collection, function(value, index, collection) {\n accumulator = initAccum\n ? (initAccum = false, value)\n : iteratee(accumulator, value, index, collection);\n });\n return accumulator;\n }\n\n /**\n * The base implementation of `_.sortBy` which uses `comparer` to define the\n * sort order of `array` and replaces criteria objects with their corresponding\n * values.\n *\n * @private\n * @param {Array} array The array to sort.\n * @param {Function} comparer The function to define sort order.\n * @returns {Array} Returns `array`.\n */\n function baseSortBy(array, comparer) {\n var length = array.length;\n\n array.sort(comparer);\n while (length--) {\n array[length] = array[length].value;\n }\n return array;\n }\n\n /**\n * The base implementation of `_.sum` and `_.sumBy` without support for\n * iteratee shorthands.\n *\n * @private\n * @param {Array} array The array to iterate over.\n * @param {Function} iteratee The function invoked per iteration.\n * @returns {number} Returns the sum.\n */\n function baseSum(array, iteratee) {\n var result,\n index = -1,\n length = array.length;\n\n while (++index < length) {\n var current = iteratee(array[index]);\n if (current !== undefined) {\n result = result === undefined ? current : (result + current);\n }\n }\n return result;\n }\n\n /**\n * The base implementation of `_.times` without support for iteratee shorthands\n * or max array length checks.\n *\n * @private\n * @param {number} n The number of times to invoke `iteratee`.\n * @param {Function} iteratee The function invoked per iteration.\n * @returns {Array} Returns the array of results.\n */\n function baseTimes(n, iteratee) {\n var index = -1,\n result = Array(n);\n\n while (++index < n) {\n result[index] = iteratee(index);\n }\n return result;\n }\n\n /**\n * The base implementation of `_.toPairs` and `_.toPairsIn` which creates an array\n * of key-value pairs for `object` corresponding to the property names of `props`.\n *\n * @private\n * @param {Object} object The object to query.\n * @param {Array} props The property names to get values for.\n * @returns {Object} Returns the key-value pairs.\n */\n function baseToPairs(object, props) {\n return arrayMap(props, function(key) {\n return [key, object[key]];\n });\n }\n\n /**\n * The base implementation of `_.unary` without support for storing metadata.\n *\n * @private\n * @param {Function} func The function to cap arguments for.\n * @returns {Function} Returns the new capped function.\n */\n function baseUnary(func) {\n return function(value) {\n return func(value);\n };\n }\n\n /**\n * The base implementation of `_.values` and `_.valuesIn` which creates an\n * array of `object` property values corresponding to the property names\n * of `props`.\n *\n * @private\n * @param {Object} object The object to query.\n * @param {Array} props The property names to get values for.\n * @returns {Object} Returns the array of property values.\n */\n function baseValues(object, props) {\n return arrayMap(props, function(key) {\n return object[key];\n });\n }\n\n /**\n * Checks if a `cache` value for `key` exists.\n *\n * @private\n * @param {Object} cache The cache to query.\n * @param {string} key The key of the entry to check.\n * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.\n */\n function cacheHas(cache, key) {\n return cache.has(key);\n }\n\n /**\n * Used by `_.trim` and `_.trimStart` to get the index of the first string symbol\n * that is not found in the character symbols.\n *\n * @private\n * @param {Array} strSymbols The string symbols to inspect.\n * @param {Array} chrSymbols The character symbols to find.\n * @returns {number} Returns the index of the first unmatched string symbol.\n */\n function charsStartIndex(strSymbols, chrSymbols) {\n var index = -1,\n length = strSymbols.length;\n\n while (++index < length && baseIndexOf(chrSymbols, strSymbols[index], 0) > -1) {}\n return index;\n }\n\n /**\n * Used by `_.trim` and `_.trimEnd` to get the index of the last string symbol\n * that is not found in the character symbols.\n *\n * @private\n * @param {Array} strSymbols The string symbols to inspect.\n * @param {Array} chrSymbols The character symbols to find.\n * @returns {number} Returns the index of the last unmatched string symbol.\n */\n function charsEndIndex(strSymbols, chrSymbols) {\n var index = strSymbols.length;\n\n while (index-- && baseIndexOf(chrSymbols, strSymbols[index], 0) > -1) {}\n return index;\n }\n\n /**\n * Gets the number of `placeholder` occurrences in `array`.\n *\n * @private\n * @param {Array} array The array to inspect.\n * @param {*} placeholder The placeholder to search for.\n * @returns {number} Returns the placeholder count.\n */\n function countHolders(array, placeholder) {\n var length = array.length,\n result = 0;\n\n while (length--) {\n if (array[length] === placeholder) {\n ++result;\n }\n }\n return result;\n }\n\n /**\n * Used by `_.deburr` to convert Latin-1 Supplement and Latin Extended-A\n * letters to basic Latin letters.\n *\n * @private\n * @param {string} letter The matched letter to deburr.\n * @returns {string} Returns the deburred letter.\n */\n var deburrLetter = basePropertyOf(deburredLetters);\n\n /**\n * Used by `_.escape` to convert characters to HTML entities.\n *\n * @private\n * @param {string} chr The matched character to escape.\n * @returns {string} Returns the escaped character.\n */\n var escapeHtmlChar = basePropertyOf(htmlEscapes);\n\n /**\n * Used by `_.template` to escape characters for inclusion in compiled string literals.\n *\n * @private\n * @param {string} chr The matched character to escape.\n * @returns {string} Returns the escaped character.\n */\n function escapeStringChar(chr) {\n return '\\\\' + stringEscapes[chr];\n }\n\n /**\n * Gets the value at `key` of `object`.\n *\n * @private\n * @param {Object} [object] The object to query.\n * @param {string} key The key of the property to get.\n * @returns {*} Returns the property value.\n */\n function getValue(object, key) {\n return object == null ? undefined : object[key];\n }\n\n /**\n * Checks if `string` contains Unicode symbols.\n *\n * @private\n * @param {string} string The string to inspect.\n * @returns {boolean} Returns `true` if a symbol is found, else `false`.\n */\n function hasUnicode(string) {\n return reHasUnicode.test(string);\n }\n\n /**\n * Checks if `string` contains a word composed of Unicode symbols.\n *\n * @private\n * @param {string} string The string to inspect.\n * @returns {boolean} Returns `true` if a word is found, else `false`.\n */\n function hasUnicodeWord(string) {\n return reHasUnicodeWord.test(string);\n }\n\n /**\n * Converts `iterator` to an array.\n *\n * @private\n * @param {Object} iterator The iterator to convert.\n * @returns {Array} Returns the converted array.\n */\n function iteratorToArray(iterator) {\n var data,\n result = [];\n\n while (!(data = iterator.next()).done) {\n result.push(data.value);\n }\n return result;\n }\n\n /**\n * Converts `map` to its key-value pairs.\n *\n * @private\n * @param {Object} map The map to convert.\n * @returns {Array} Returns the key-value pairs.\n */\n function mapToArray(map) {\n var index = -1,\n result = Array(map.size);\n\n map.forEach(function(value, key) {\n result[++index] = [key, value];\n });\n return result;\n }\n\n /**\n * Creates a unary function that invokes `func` with its argument transformed.\n *\n * @private\n * @param {Function} func The function to wrap.\n * @param {Function} transform The argument transform.\n * @returns {Function} Returns the new function.\n */\n function overArg(func, transform) {\n return function(arg) {\n return func(transform(arg));\n };\n }\n\n /**\n * Replaces all `placeholder` elements in `array` with an internal placeholder\n * and returns an array of their indexes.\n *\n * @private\n * @param {Array} array The array to modify.\n * @param {*} placeholder The placeholder to replace.\n * @returns {Array} Returns the new array of placeholder indexes.\n */\n function replaceHolders(array, placeholder) {\n var index = -1,\n length = array.length,\n resIndex = 0,\n result = [];\n\n while (++index < length) {\n var value = array[index];\n if (value === placeholder || value === PLACEHOLDER) {\n array[index] = PLACEHOLDER;\n result[resIndex++] = index;\n }\n }\n return result;\n }\n\n /**\n * Converts `set` to an array of its values.\n *\n * @private\n * @param {Object} set The set to convert.\n * @returns {Array} Returns the values.\n */\n function setToArray(set) {\n var index = -1,\n result = Array(set.size);\n\n set.forEach(function(value) {\n result[++index] = value;\n });\n return result;\n }\n\n /**\n * Converts `set` to its value-value pairs.\n *\n * @private\n * @param {Object} set The set to convert.\n * @returns {Array} Returns the value-value pairs.\n */\n function setToPairs(set) {\n var index = -1,\n result = Array(set.size);\n\n set.forEach(function(value) {\n result[++index] = [value, value];\n });\n return result;\n }\n\n /**\n * A specialized version of `_.indexOf` which performs strict equality\n * comparisons of values, i.e. `===`.\n *\n * @private\n * @param {Array} array The array to inspect.\n * @param {*} value The value to search for.\n * @param {number} fromIndex The index to search from.\n * @returns {number} Returns the index of the matched value, else `-1`.\n */\n function strictIndexOf(array, value, fromIndex) {\n var index = fromIndex - 1,\n length = array.length;\n\n while (++index < length) {\n if (array[index] === value) {\n return index;\n }\n }\n return -1;\n }\n\n /**\n * A specialized version of `_.lastIndexOf` which performs strict equality\n * comparisons of values, i.e. `===`.\n *\n * @private\n * @param {Array} array The array to inspect.\n * @param {*} value The value to search for.\n * @param {number} fromIndex The index to search from.\n * @returns {number} Returns the index of the matched value, else `-1`.\n */\n function strictLastIndexOf(array, value, fromIndex) {\n var index = fromIndex + 1;\n while (index--) {\n if (array[index] === value) {\n return index;\n }\n }\n return index;\n }\n\n /**\n * Gets the number of symbols in `string`.\n *\n * @private\n * @param {string} string The string to inspect.\n * @returns {number} Returns the string size.\n */\n function stringSize(string) {\n return hasUnicode(string)\n ? unicodeSize(string)\n : asciiSize(string);\n }\n\n /**\n * Converts `string` to an array.\n *\n * @private\n * @param {string} string The string to convert.\n * @returns {Array} Returns the converted array.\n */\n function stringToArray(string) {\n return hasUnicode(string)\n ? unicodeToArray(string)\n : asciiToArray(string);\n }\n\n /**\n * Used by `_.unescape` to convert HTML entities to characters.\n *\n * @private\n * @param {string} chr The matched character to unescape.\n * @returns {string} Returns the unescaped character.\n */\n var unescapeHtmlChar = basePropertyOf(htmlUnescapes);\n\n /**\n * Gets the size of a Unicode `string`.\n *\n * @private\n * @param {string} string The string inspect.\n * @returns {number} Returns the string size.\n */\n function unicodeSize(string) {\n var result = reUnicode.lastIndex = 0;\n while (reUnicode.test(string)) {\n ++result;\n }\n return result;\n }\n\n /**\n * Converts a Unicode `string` to an array.\n *\n * @private\n * @param {string} string The string to convert.\n * @returns {Array} Returns the converted array.\n */\n function unicodeToArray(string) {\n return string.match(reUnicode) || [];\n }\n\n /**\n * Splits a Unicode `string` into an array of its words.\n *\n * @private\n * @param {string} The string to inspect.\n * @returns {Array} Returns the words of `string`.\n */\n function unicodeWords(string) {\n return string.match(reUnicodeWord) || [];\n }\n\n /*--------------------------------------------------------------------------*/\n\n /**\n * Create a new pristine `lodash` function using the `context` object.\n *\n * @static\n * @memberOf _\n * @since 1.1.0\n * @category Util\n * @param {Object} [context=root] The context object.\n * @returns {Function} Returns a new `lodash` function.\n * @example\n *\n * _.mixin({ 'foo': _.constant('foo') });\n *\n * var lodash = _.runInContext();\n * lodash.mixin({ 'bar': lodash.constant('bar') });\n *\n * _.isFunction(_.foo);\n * // => true\n * _.isFunction(_.bar);\n * // => false\n *\n * lodash.isFunction(lodash.foo);\n * // => false\n * lodash.isFunction(lodash.bar);\n * // => true\n *\n * // Create a suped-up `defer` in Node.js.\n * var defer = _.runInContext({ 'setTimeout': setImmediate }).defer;\n */\n var runInContext = (function runInContext(context) {\n context = context == null ? root : _.defaults(root.Object(), context, _.pick(root, contextProps));\n\n /** Built-in constructor references. */\n var Array = context.Array,\n Date = context.Date,\n Error = context.Error,\n Function = context.Function,\n Math = context.Math,\n Object = context.Object,\n RegExp = context.RegExp,\n String = context.String,\n TypeError = context.TypeError;\n\n /** Used for built-in method references. */\n var arrayProto = Array.prototype,\n funcProto = Function.prototype,\n objectProto = Object.prototype;\n\n /** Used to detect overreaching core-js shims. */\n var coreJsData = context['__core-js_shared__'];\n\n /** Used to resolve the decompiled source of functions. */\n var funcToString = funcProto.toString;\n\n /** Used to check objects for own properties. */\n var hasOwnProperty = objectProto.hasOwnProperty;\n\n /** Used to generate unique IDs. */\n var idCounter = 0;\n\n /** Used to detect methods masquerading as native. */\n var maskSrcKey = (function() {\n var uid = /[^.]+$/.exec(coreJsData && coreJsData.keys && coreJsData.keys.IE_PROTO || '');\n return uid ? ('Symbol(src)_1.' + uid) : '';\n }());\n\n /**\n * Used to resolve the\n * [`toStringTag`](http://ecma-international.org/ecma-262/7.0/#sec-object.prototype.tostring)\n * of values.\n */\n var nativeObjectToString = objectProto.toString;\n\n /** Used to infer the `Object` constructor. */\n var objectCtorString = funcToString.call(Object);\n\n /** Used to restore the original `_` reference in `_.noConflict`. */\n var oldDash = root._;\n\n /** Used to detect if a method is native. */\n var reIsNative = RegExp('^' +\n funcToString.call(hasOwnProperty).replace(reRegExpChar, '\\\\$&')\n .replace(/hasOwnProperty|(function).*?(?=\\\\\\()| for .+?(?=\\\\\\])/g, '$1.*?') + '$'\n );\n\n /** Built-in value references. */\n var Buffer = moduleExports ? context.Buffer : undefined,\n Symbol = context.Symbol,\n Uint8Array = context.Uint8Array,\n allocUnsafe = Buffer ? Buffer.allocUnsafe : undefined,\n getPrototype = overArg(Object.getPrototypeOf, Object),\n objectCreate = Object.create,\n propertyIsEnumerable = objectProto.propertyIsEnumerable,\n splice = arrayProto.splice,\n spreadableSymbol = Symbol ? Symbol.isConcatSpreadable : undefined,\n symIterator = Symbol ? Symbol.iterator : undefined,\n symToStringTag = Symbol ? Symbol.toStringTag : undefined;\n\n var defineProperty = (function() {\n try {\n var func = getNative(Object, 'defineProperty');\n func({}, '', {});\n return func;\n } catch (e) {}\n }());\n\n /** Mocked built-ins. */\n var ctxClearTimeout = context.clearTimeout !== root.clearTimeout && context.clearTimeout,\n ctxNow = Date && Date.now !== root.Date.now && Date.now,\n ctxSetTimeout = context.setTimeout !== root.setTimeout && context.setTimeout;\n\n /* Built-in method references for those with the same name as other `lodash` methods. */\n var nativeCeil = Math.ceil,\n nativeFloor = Math.floor,\n nativeGetSymbols = Object.getOwnPropertySymbols,\n nativeIsBuffer = Buffer ? Buffer.isBuffer : undefined,\n nativeIsFinite = context.isFinite,\n nativeJoin = arrayProto.join,\n nativeKeys = overArg(Object.keys, Object),\n nativeMax = Math.max,\n nativeMin = Math.min,\n nativeNow = Date.now,\n nativeParseInt = context.parseInt,\n nativeRandom = Math.random,\n nativeReverse = arrayProto.reverse;\n\n /* Built-in method references that are verified to be native. */\n var DataView = getNative(context, 'DataView'),\n Map = getNative(context, 'Map'),\n Promise = getNative(context, 'Promise'),\n Set = getNative(context, 'Set'),\n WeakMap = getNative(context, 'WeakMap'),\n nativeCreate = getNative(Object, 'create');\n\n /** Used to store function metadata. */\n var metaMap = WeakMap && new WeakMap;\n\n /** Used to lookup unminified function names. */\n var realNames = {};\n\n /** Used to detect maps, sets, and weakmaps. */\n var dataViewCtorString = toSource(DataView),\n mapCtorString = toSource(Map),\n promiseCtorString = toSource(Promise),\n setCtorString = toSource(Set),\n weakMapCtorString = toSource(WeakMap);\n\n /** Used to convert symbols to primitives and strings. */\n var symbolProto = Symbol ? Symbol.prototype : undefined,\n symbolValueOf = symbolProto ? symbolProto.valueOf : undefined,\n symbolToString = symbolProto ? symbolProto.toString : undefined;\n\n /*------------------------------------------------------------------------*/\n\n /**\n * Creates a `lodash` object which wraps `value` to enable implicit method\n * chain sequences. Methods that operate on and return arrays, collections,\n * and functions can be chained together. Methods that retrieve a single value\n * or may return a primitive value will automatically end the chain sequence\n * and return the unwrapped value. Otherwise, the value must be unwrapped\n * with `_#value`.\n *\n * Explicit chain sequences, which must be unwrapped with `_#value`, may be\n * enabled using `_.chain`.\n *\n * The execution of chained methods is lazy, that is, it's deferred until\n * `_#value` is implicitly or explicitly called.\n *\n * Lazy evaluation allows several methods to support shortcut fusion.\n * Shortcut fusion is an optimization to merge iteratee calls; this avoids\n * the creation of intermediate arrays and can greatly reduce the number of\n * iteratee executions. Sections of a chain sequence qualify for shortcut\n * fusion if the section is applied to an array and iteratees accept only\n * one argument. The heuristic for whether a section qualifies for shortcut\n * fusion is subject to change.\n *\n * Chaining is supported in custom builds as long as the `_#value` method is\n * directly or indirectly included in the build.\n *\n * In addition to lodash methods, wrappers have `Array` and `String` methods.\n *\n * The wrapper `Array` methods are:\n * `concat`, `join`, `pop`, `push`, `shift`, `sort`, `splice`, and `unshift`\n *\n * The wrapper `String` methods are:\n * `replace` and `split`\n *\n * The wrapper methods that support shortcut fusion are:\n * `at`, `compact`, `drop`, `dropRight`, `dropWhile`, `filter`, `find`,\n * `findLast`, `head`, `initial`, `last`, `map`, `reject`, `reverse`, `slice`,\n * `tail`, `take`, `takeRight`, `takeRightWhile`, `takeWhile`, and `toArray`\n *\n * The chainable wrapper methods are:\n * `after`, `ary`, `assign`, `assignIn`, `assignInWith`, `assignWith`, `at`,\n * `before`, `bind`, `bindAll`, `bindKey`, `castArray`, `chain`, `chunk`,\n * `commit`, `compact`, `concat`, `conforms`, `constant`, `countBy`, `create`,\n * `curry`, `debounce`, `defaults`, `defaultsDeep`, `defer`, `delay`,\n * `difference`, `differenceBy`, `differenceWith`, `drop`, `dropRight`,\n * `dropRightWhile`, `dropWhile`, `extend`, `extendWith`, `fill`, `filter`,\n * `flatMap`, `flatMapDeep`, `flatMapDepth`, `flatten`, `flattenDeep`,\n * `flattenDepth`, `flip`, `flow`, `flowRight`, `fromPairs`, `functions`,\n * `functionsIn`, `groupBy`, `initial`, `intersection`, `intersectionBy`,\n * `intersectionWith`, `invert`, `invertBy`, `invokeMap`, `iteratee`, `keyBy`,\n * `keys`, `keysIn`, `map`, `mapKeys`, `mapValues`, `matches`, `matchesProperty`,\n * `memoize`, `merge`, `mergeWith`, `method`, `methodOf`, `mixin`, `negate`,\n * `nthArg`, `omit`, `omitBy`, `once`, `orderBy`, `over`, `overArgs`,\n * `overEvery`, `overSome`, `partial`, `partialRight`, `partition`, `pick`,\n * `pickBy`, `plant`, `property`, `propertyOf`, `pull`, `pullAll`, `pullAllBy`,\n * `pullAllWith`, `pullAt`, `push`, `range`, `rangeRight`, `rearg`, `reject`,\n * `remove`, `rest`, `reverse`, `sampleSize`, `set`, `setWith`, `shuffle`,\n * `slice`, `sort`, `sortBy`, `splice`, `spread`, `tail`, `take`, `takeRight`,\n * `takeRightWhile`, `takeWhile`, `tap`, `throttle`, `thru`, `toArray`,\n * `toPairs`, `toPairsIn`, `toPath`, `toPlainObject`, `transform`, `unary`,\n * `union`, `unionBy`, `unionWith`, `uniq`, `uniqBy`, `uniqWith`, `unset`,\n * `unshift`, `unzip`, `unzipWith`, `update`, `updateWith`, `values`,\n * `valuesIn`, `without`, `wrap`, `xor`, `xorBy`, `xorWith`, `zip`,\n * `zipObject`, `zipObjectDeep`, and `zipWith`\n *\n * The wrapper methods that are **not** chainable by default are:\n * `add`, `attempt`, `camelCase`, `capitalize`, `ceil`, `clamp`, `clone`,\n * `cloneDeep`, `cloneDeepWith`, `cloneWith`, `conformsTo`, `deburr`,\n * `defaultTo`, `divide`, `each`, `eachRight`, `endsWith`, `eq`, `escape`,\n * `escapeRegExp`, `every`, `find`, `findIndex`, `findKey`, `findLast`,\n * `findLastIndex`, `findLastKey`, `first`, `floor`, `forEach`, `forEachRight`,\n * `forIn`, `forInRight`, `forOwn`, `forOwnRight`, `get`, `gt`, `gte`, `has`,\n * `hasIn`, `head`, `identity`, `includes`, `indexOf`, `inRange`, `invoke`,\n * `isArguments`, `isArray`, `isArrayBuffer`, `isArrayLike`, `isArrayLikeObject`,\n * `isBoolean`, `isBuffer`, `isDate`, `isElement`, `isEmpty`, `isEqual`,\n * `isEqualWith`, `isError`, `isFinite`, `isFunction`, `isInteger`, `isLength`,\n * `isMap`, `isMatch`, `isMatchWith`, `isNaN`, `isNative`, `isNil`, `isNull`,\n * `isNumber`, `isObject`, `isObjectLike`, `isPlainObject`, `isRegExp`,\n * `isSafeInteger`, `isSet`, `isString`, `isUndefined`, `isTypedArray`,\n * `isWeakMap`, `isWeakSet`, `join`, `kebabCase`, `last`, `lastIndexOf`,\n * `lowerCase`, `lowerFirst`, `lt`, `lte`, `max`, `maxBy`, `mean`, `meanBy`,\n * `min`, `minBy`, `multiply`, `noConflict`, `noop`, `now`, `nth`, `pad`,\n * `padEnd`, `padStart`, `parseInt`, `pop`, `random`, `reduce`, `reduceRight`,\n * `repeat`, `result`, `round`, `runInContext`, `sample`, `shift`, `size`,\n * `snakeCase`, `some`, `sortedIndex`, `sortedIndexBy`, `sortedLastIndex`,\n * `sortedLastIndexBy`, `startCase`, `startsWith`, `stubArray`, `stubFalse`,\n * `stubObject`, `stubString`, `stubTrue`, `subtract`, `sum`, `sumBy`,\n * `template`, `times`, `toFinite`, `toInteger`, `toJSON`, `toLength`,\n * `toLower`, `toNumber`, `toSafeInteger`, `toString`, `toUpper`, `trim`,\n * `trimEnd`, `trimStart`, `truncate`, `unescape`, `uniqueId`, `upperCase`,\n * `upperFirst`, `value`, and `words`\n *\n * @name _\n * @constructor\n * @category Seq\n * @param {*} value The value to wrap in a `lodash` instance.\n * @returns {Object} Returns the new `lodash` wrapper instance.\n * @example\n *\n * function square(n) {\n * return n * n;\n * }\n *\n * var wrapped = _([1, 2, 3]);\n *\n * // Returns an unwrapped value.\n * wrapped.reduce(_.add);\n * // => 6\n *\n * // Returns a wrapped value.\n * var squares = wrapped.map(square);\n *\n * _.isArray(squares);\n * // => false\n *\n * _.isArray(squares.value());\n * // => true\n */\n function lodash(value) {\n if (isObjectLike(value) && !isArray(value) && !(value instanceof LazyWrapper)) {\n if (value instanceof LodashWrapper) {\n return value;\n }\n if (hasOwnProperty.call(value, '__wrapped__')) {\n return wrapperClone(value);\n }\n }\n return new LodashWrapper(value);\n }\n\n /**\n * The base implementation of `_.create` without support for assigning\n * properties to the created object.\n *\n * @private\n * @param {Object} proto The object to inherit from.\n * @returns {Object} Returns the new object.\n */\n var baseCreate = (function() {\n function object() {}\n return function(proto) {\n if (!isObject(proto)) {\n return {};\n }\n if (objectCreate) {\n return objectCreate(proto);\n }\n object.prototype = proto;\n var result = new object;\n object.prototype = undefined;\n return result;\n };\n }());\n\n /**\n * The function whose prototype chain sequence wrappers inherit from.\n *\n * @private\n */\n function baseLodash() {\n // No operation performed.\n }\n\n /**\n * The base constructor for creating `lodash` wrapper objects.\n *\n * @private\n * @param {*} value The value to wrap.\n * @param {boolean} [chainAll] Enable explicit method chain sequences.\n */\n function LodashWrapper(value, chainAll) {\n this.__wrapped__ = value;\n this.__actions__ = [];\n this.__chain__ = !!chainAll;\n this.__index__ = 0;\n this.__values__ = undefined;\n }\n\n /**\n * By default, the template delimiters used by lodash are like those in\n * embedded Ruby (ERB) as well as ES2015 template strings. Change the\n * following template settings to use alternative delimiters.\n *\n * @static\n * @memberOf _\n * @type {Object}\n */\n lodash.templateSettings = {\n\n /**\n * Used to detect `data` property values to be HTML-escaped.\n *\n * @memberOf _.templateSettings\n * @type {RegExp}\n */\n 'escape': reEscape,\n\n /**\n * Used to detect code to be evaluated.\n *\n * @memberOf _.templateSettings\n * @type {RegExp}\n */\n 'evaluate': reEvaluate,\n\n /**\n * Used to detect `data` property values to inject.\n *\n * @memberOf _.templateSettings\n * @type {RegExp}\n */\n 'interpolate': reInterpolate,\n\n /**\n * Used to reference the data object in the template text.\n *\n * @memberOf _.templateSettings\n * @type {string}\n */\n 'variable': '',\n\n /**\n * Used to import variables into the compiled template.\n *\n * @memberOf _.templateSettings\n * @type {Object}\n */\n 'imports': {\n\n /**\n * A reference to the `lodash` function.\n *\n * @memberOf _.templateSettings.imports\n * @type {Function}\n */\n '_': lodash\n }\n };\n\n // Ensure wrappers are instances of `baseLodash`.\n lodash.prototype = baseLodash.prototype;\n lodash.prototype.constructor = lodash;\n\n LodashWrapper.prototype = baseCreate(baseLodash.prototype);\n LodashWrapper.prototype.constructor = LodashWrapper;\n\n /*------------------------------------------------------------------------*/\n\n /**\n * Creates a lazy wrapper object which wraps `value` to enable lazy evaluation.\n *\n * @private\n * @constructor\n * @param {*} value The value to wrap.\n */\n function LazyWrapper(value) {\n this.__wrapped__ = value;\n this.__actions__ = [];\n this.__dir__ = 1;\n this.__filtered__ = false;\n this.__iteratees__ = [];\n this.__takeCount__ = MAX_ARRAY_LENGTH;\n this.__views__ = [];\n }\n\n /**\n * Creates a clone of the lazy wrapper object.\n *\n * @private\n * @name clone\n * @memberOf LazyWrapper\n * @returns {Object} Returns the cloned `LazyWrapper` object.\n */\n function lazyClone() {\n var result = new LazyWrapper(this.__wrapped__);\n result.__actions__ = copyArray(this.__actions__);\n result.__dir__ = this.__dir__;\n result.__filtered__ = this.__filtered__;\n result.__iteratees__ = copyArray(this.__iteratees__);\n result.__takeCount__ = this.__takeCount__;\n result.__views__ = copyArray(this.__views__);\n return result;\n }\n\n /**\n * Reverses the direction of lazy iteration.\n *\n * @private\n * @name reverse\n * @memberOf LazyWrapper\n * @returns {Object} Returns the new reversed `LazyWrapper` object.\n */\n function lazyReverse() {\n if (this.__filtered__) {\n var result = new LazyWrapper(this);\n result.__dir__ = -1;\n result.__filtered__ = true;\n } else {\n result = this.clone();\n result.__dir__ *= -1;\n }\n return result;\n }\n\n /**\n * Extracts the unwrapped value from its lazy wrapper.\n *\n * @private\n * @name value\n * @memberOf LazyWrapper\n * @returns {*} Returns the unwrapped value.\n */\n function lazyValue() {\n var array = this.__wrapped__.value(),\n dir = this.__dir__,\n isArr = isArray(array),\n isRight = dir < 0,\n arrLength = isArr ? array.length : 0,\n view = getView(0, arrLength, this.__views__),\n start = view.start,\n end = view.end,\n length = end - start,\n index = isRight ? end : (start - 1),\n iteratees = this.__iteratees__,\n iterLength = iteratees.length,\n resIndex = 0,\n takeCount = nativeMin(length, this.__takeCount__);\n\n if (!isArr || (!isRight && arrLength == length && takeCount == length)) {\n return baseWrapperValue(array, this.__actions__);\n }\n var result = [];\n\n outer:\n while (length-- && resIndex < takeCount) {\n index += dir;\n\n var iterIndex = -1,\n value = array[index];\n\n while (++iterIndex < iterLength) {\n var data = iteratees[iterIndex],\n iteratee = data.iteratee,\n type = data.type,\n computed = iteratee(value);\n\n if (type == LAZY_MAP_FLAG) {\n value = computed;\n } else if (!computed) {\n if (type == LAZY_FILTER_FLAG) {\n continue outer;\n } else {\n break outer;\n }\n }\n }\n result[resIndex++] = value;\n }\n return result;\n }\n\n // Ensure `LazyWrapper` is an instance of `baseLodash`.\n LazyWrapper.prototype = baseCreate(baseLodash.prototype);\n LazyWrapper.prototype.constructor = LazyWrapper;\n\n /*------------------------------------------------------------------------*/\n\n /**\n * Creates a hash object.\n *\n * @private\n * @constructor\n * @param {Array} [entries] The key-value pairs to cache.\n */\n function Hash(entries) {\n var index = -1,\n length = entries == null ? 0 : entries.length;\n\n this.clear();\n while (++index < length) {\n var entry = entries[index];\n this.set(entry[0], entry[1]);\n }\n }\n\n /**\n * Removes all key-value entries from the hash.\n *\n * @private\n * @name clear\n * @memberOf Hash\n */\n function hashClear() {\n this.__data__ = nativeCreate ? nativeCreate(null) : {};\n this.size = 0;\n }\n\n /**\n * Removes `key` and its value from the hash.\n *\n * @private\n * @name delete\n * @memberOf Hash\n * @param {Object} hash The hash to modify.\n * @param {string} key The key of the value to remove.\n * @returns {boolean} Returns `true` if the entry was removed, else `false`.\n */\n function hashDelete(key) {\n var result = this.has(key) && delete this.__data__[key];\n this.size -= result ? 1 : 0;\n return result;\n }\n\n /**\n * Gets the hash value for `key`.\n *\n * @private\n * @name get\n * @memberOf Hash\n * @param {string} key The key of the value to get.\n * @returns {*} Returns the entry value.\n */\n function hashGet(key) {\n var data = this.__data__;\n if (nativeCreate) {\n var result = data[key];\n return result === HASH_UNDEFINED ? undefined : result;\n }\n return hasOwnProperty.call(data, key) ? data[key] : undefined;\n }\n\n /**\n * Checks if a hash value for `key` exists.\n *\n * @private\n * @name has\n * @memberOf Hash\n * @param {string} key The key of the entry to check.\n * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.\n */\n function hashHas(key) {\n var data = this.__data__;\n return nativeCreate ? (data[key] !== undefined) : hasOwnProperty.call(data, key);\n }\n\n /**\n * Sets the hash `key` to `value`.\n *\n * @private\n * @name set\n * @memberOf Hash\n * @param {string} key The key of the value to set.\n * @param {*} value The value to set.\n * @returns {Object} Returns the hash instance.\n */\n function hashSet(key, value) {\n var data = this.__data__;\n this.size += this.has(key) ? 0 : 1;\n data[key] = (nativeCreate && value === undefined) ? HASH_UNDEFINED : value;\n return this;\n }\n\n // Add methods to `Hash`.\n Hash.prototype.clear = hashClear;\n Hash.prototype['delete'] = hashDelete;\n Hash.prototype.get = hashGet;\n Hash.prototype.has = hashHas;\n Hash.prototype.set = hashSet;\n\n /*------------------------------------------------------------------------*/\n\n /**\n * Creates an list cache object.\n *\n * @private\n * @constructor\n * @param {Array} [entries] The key-value pairs to cache.\n */\n function ListCache(entries) {\n var index = -1,\n length = entries == null ? 0 : entries.length;\n\n this.clear();\n while (++index < length) {\n var entry = entries[index];\n this.set(entry[0], entry[1]);\n }\n }\n\n /**\n * Removes all key-value entries from the list cache.\n *\n * @private\n * @name clear\n * @memberOf ListCache\n */\n function listCacheClear() {\n this.__data__ = [];\n this.size = 0;\n }\n\n /**\n * Removes `key` and its value from the list cache.\n *\n * @private\n * @name delete\n * @memberOf ListCache\n * @param {string} key The key of the value to remove.\n * @returns {boolean} Returns `true` if the entry was removed, else `false`.\n */\n function listCacheDelete(key) {\n var data = this.__data__,\n index = assocIndexOf(data, key);\n\n if (index < 0) {\n return false;\n }\n var lastIndex = data.length - 1;\n if (index == lastIndex) {\n data.pop();\n } else {\n splice.call(data, index, 1);\n }\n --this.size;\n return true;\n }\n\n /**\n * Gets the list cache value for `key`.\n *\n * @private\n * @name get\n * @memberOf ListCache\n * @param {string} key The key of the value to get.\n * @returns {*} Returns the entry value.\n */\n function listCacheGet(key) {\n var data = this.__data__,\n index = assocIndexOf(data, key);\n\n return index < 0 ? undefined : data[index][1];\n }\n\n /**\n * Checks if a list cache value for `key` exists.\n *\n * @private\n * @name has\n * @memberOf ListCache\n * @param {string} key The key of the entry to check.\n * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.\n */\n function listCacheHas(key) {\n return assocIndexOf(this.__data__, key) > -1;\n }\n\n /**\n * Sets the list cache `key` to `value`.\n *\n * @private\n * @name set\n * @memberOf ListCache\n * @param {string} key The key of the value to set.\n * @param {*} value The value to set.\n * @returns {Object} Returns the list cache instance.\n */\n function listCacheSet(key, value) {\n var data = this.__data__,\n index = assocIndexOf(data, key);\n\n if (index < 0) {\n ++this.size;\n data.push([key, value]);\n } else {\n data[index][1] = value;\n }\n return this;\n }\n\n // Add methods to `ListCache`.\n ListCache.prototype.clear = listCacheClear;\n ListCache.prototype['delete'] = listCacheDelete;\n ListCache.prototype.get = listCacheGet;\n ListCache.prototype.has = listCacheHas;\n ListCache.prototype.set = listCacheSet;\n\n /*------------------------------------------------------------------------*/\n\n /**\n * Creates a map cache object to store key-value pairs.\n *\n * @private\n * @constructor\n * @param {Array} [entries] The key-value pairs to cache.\n */\n function MapCache(entries) {\n var index = -1,\n length = entries == null ? 0 : entries.length;\n\n this.clear();\n while (++index < length) {\n var entry = entries[index];\n this.set(entry[0], entry[1]);\n }\n }\n\n /**\n * Removes all key-value entries from the map.\n *\n * @private\n * @name clear\n * @memberOf MapCache\n */\n function mapCacheClear() {\n this.size = 0;\n this.__data__ = {\n 'hash': new Hash,\n 'map': new (Map || ListCache),\n 'string': new Hash\n };\n }\n\n /**\n * Removes `key` and its value from the map.\n *\n * @private\n * @name delete\n * @memberOf MapCache\n * @param {string} key The key of the value to remove.\n * @returns {boolean} Returns `true` if the entry was removed, else `false`.\n */\n function mapCacheDelete(key) {\n var result = getMapData(this, key)['delete'](key);\n this.size -= result ? 1 : 0;\n return result;\n }\n\n /**\n * Gets the map value for `key`.\n *\n * @private\n * @name get\n * @memberOf MapCache\n * @param {string} key The key of the value to get.\n * @returns {*} Returns the entry value.\n */\n function mapCacheGet(key) {\n return getMapData(this, key).get(key);\n }\n\n /**\n * Checks if a map value for `key` exists.\n *\n * @private\n * @name has\n * @memberOf MapCache\n * @param {string} key The key of the entry to check.\n * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.\n */\n function mapCacheHas(key) {\n return getMapData(this, key).has(key);\n }\n\n /**\n * Sets the map `key` to `value`.\n *\n * @private\n * @name set\n * @memberOf MapCache\n * @param {string} key The key of the value to set.\n * @param {*} value The value to set.\n * @returns {Object} Returns the map cache instance.\n */\n function mapCacheSet(key, value) {\n var data = getMapData(this, key),\n size = data.size;\n\n data.set(key, value);\n this.size += data.size == size ? 0 : 1;\n return this;\n }\n\n // Add methods to `MapCache`.\n MapCache.prototype.clear = mapCacheClear;\n MapCache.prototype['delete'] = mapCacheDelete;\n MapCache.prototype.get = mapCacheGet;\n MapCache.prototype.has = mapCacheHas;\n MapCache.prototype.set = mapCacheSet;\n\n /*------------------------------------------------------------------------*/\n\n /**\n *\n * Creates an array cache object to store unique values.\n *\n * @private\n * @constructor\n * @param {Array} [values] The values to cache.\n */\n function SetCache(values) {\n var index = -1,\n length = values == null ? 0 : values.length;\n\n this.__data__ = new MapCache;\n while (++index < length) {\n this.add(values[index]);\n }\n }\n\n /**\n * Adds `value` to the array cache.\n *\n * @private\n * @name add\n * @memberOf SetCache\n * @alias push\n * @param {*} value The value to cache.\n * @returns {Object} Returns the cache instance.\n */\n function setCacheAdd(value) {\n this.__data__.set(value, HASH_UNDEFINED);\n return this;\n }\n\n /**\n * Checks if `value` is in the array cache.\n *\n * @private\n * @name has\n * @memberOf SetCache\n * @param {*} value The value to search for.\n * @returns {number} Returns `true` if `value` is found, else `false`.\n */\n function setCacheHas(value) {\n return this.__data__.has(value);\n }\n\n // Add methods to `SetCache`.\n SetCache.prototype.add = SetCache.prototype.push = setCacheAdd;\n SetCache.prototype.has = setCacheHas;\n\n /*------------------------------------------------------------------------*/\n\n /**\n * Creates a stack cache object to store key-value pairs.\n *\n * @private\n * @constructor\n * @param {Array} [entries] The key-value pairs to cache.\n */\n function Stack(entries) {\n var data = this.__data__ = new ListCache(entries);\n this.size = data.size;\n }\n\n /**\n * Removes all key-value entries from the stack.\n *\n * @private\n * @name clear\n * @memberOf Stack\n */\n function stackClear() {\n this.__data__ = new ListCache;\n this.size = 0;\n }\n\n /**\n * Removes `key` and its value from the stack.\n *\n * @private\n * @name delete\n * @memberOf Stack\n * @param {string} key The key of the value to remove.\n * @returns {boolean} Returns `true` if the entry was removed, else `false`.\n */\n function stackDelete(key) {\n var data = this.__data__,\n result = data['delete'](key);\n\n this.size = data.size;\n return result;\n }\n\n /**\n * Gets the stack value for `key`.\n *\n * @private\n * @name get\n * @memberOf Stack\n * @param {string} key The key of the value to get.\n * @returns {*} Returns the entry value.\n */\n function stackGet(key) {\n return this.__data__.get(key);\n }\n\n /**\n * Checks if a stack value for `key` exists.\n *\n * @private\n * @name has\n * @memberOf Stack\n * @param {string} key The key of the entry to check.\n * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.\n */\n function stackHas(key) {\n return this.__data__.has(key);\n }\n\n /**\n * Sets the stack `key` to `value`.\n *\n * @private\n * @name set\n * @memberOf Stack\n * @param {string} key The key of the value to set.\n * @param {*} value The value to set.\n * @returns {Object} Returns the stack cache instance.\n */\n function stackSet(key, value) {\n var data = this.__data__;\n if (data instanceof ListCache) {\n var pairs = data.__data__;\n if (!Map || (pairs.length < LARGE_ARRAY_SIZE - 1)) {\n pairs.push([key, value]);\n this.size = ++data.size;\n return this;\n }\n data = this.__data__ = new MapCache(pairs);\n }\n data.set(key, value);\n this.size = data.size;\n return this;\n }\n\n // Add methods to `Stack`.\n Stack.prototype.clear = stackClear;\n Stack.prototype['delete'] = stackDelete;\n Stack.prototype.get = stackGet;\n Stack.prototype.has = stackHas;\n Stack.prototype.set = stackSet;\n\n /*------------------------------------------------------------------------*/\n\n /**\n * Creates an array of the enumerable property names of the array-like `value`.\n *\n * @private\n * @param {*} value The value to query.\n * @param {boolean} inherited Specify returning inherited property names.\n * @returns {Array} Returns the array of property names.\n */\n function arrayLikeKeys(value, inherited) {\n var isArr = isArray(value),\n isArg = !isArr && isArguments(value),\n isBuff = !isArr && !isArg && isBuffer(value),\n isType = !isArr && !isArg && !isBuff && isTypedArray(value),\n skipIndexes = isArr || isArg || isBuff || isType,\n result = skipIndexes ? baseTimes(value.length, String) : [],\n length = result.length;\n\n for (var key in value) {\n if ((inherited || hasOwnProperty.call(value, key)) &&\n !(skipIndexes && (\n // Safari 9 has enumerable `arguments.length` in strict mode.\n key == 'length' ||\n // Node.js 0.10 has enumerable non-index properties on buffers.\n (isBuff && (key == 'offset' || key == 'parent')) ||\n // PhantomJS 2 has enumerable non-index properties on typed arrays.\n (isType && (key == 'buffer' || key == 'byteLength' || key == 'byteOffset')) ||\n // Skip index properties.\n isIndex(key, length)\n ))) {\n result.push(key);\n }\n }\n return result;\n }\n\n /**\n * A specialized version of `_.sample` for arrays.\n *\n * @private\n * @param {Array} array The array to sample.\n * @returns {*} Returns the random element.\n */\n function arraySample(array) {\n var length = array.length;\n return length ? array[baseRandom(0, length - 1)] : undefined;\n }\n\n /**\n * A specialized version of `_.sampleSize` for arrays.\n *\n * @private\n * @param {Array} array The array to sample.\n * @param {number} n The number of elements to sample.\n * @returns {Array} Returns the random elements.\n */\n function arraySampleSize(array, n) {\n return shuffleSelf(copyArray(array), baseClamp(n, 0, array.length));\n }\n\n /**\n * A specialized version of `_.shuffle` for arrays.\n *\n * @private\n * @param {Array} array The array to shuffle.\n * @returns {Array} Returns the new shuffled array.\n */\n function arrayShuffle(array) {\n return shuffleSelf(copyArray(array));\n }\n\n /**\n * This function is like `assignValue` except that it doesn't assign\n * `undefined` values.\n *\n * @private\n * @param {Object} object The object to modify.\n * @param {string} key The key of the property to assign.\n * @param {*} value The value to assign.\n */\n function assignMergeValue(object, key, value) {\n if ((value !== undefined && !eq(object[key], value)) ||\n (value === undefined && !(key in object))) {\n baseAssignValue(object, key, value);\n }\n }\n\n /**\n * Assigns `value` to `key` of `object` if the existing value is not equivalent\n * using [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)\n * for equality comparisons.\n *\n * @private\n * @param {Object} object The object to modify.\n * @param {string} key The key of the property to assign.\n * @param {*} value The value to assign.\n */\n function assignValue(object, key, value) {\n var objValue = object[key];\n if (!(hasOwnProperty.call(object, key) && eq(objValue, value)) ||\n (value === undefined && !(key in object))) {\n baseAssignValue(object, key, value);\n }\n }\n\n /**\n * Gets the index at which the `key` is found in `array` of key-value pairs.\n *\n * @private\n * @param {Array} array The array to inspect.\n * @param {*} key The key to search for.\n * @returns {number} Returns the index of the matched value, else `-1`.\n */\n function assocIndexOf(array, key) {\n var length = array.length;\n while (length--) {\n if (eq(array[length][0], key)) {\n return length;\n }\n }\n return -1;\n }\n\n /**\n * Aggregates elements of `collection` on `accumulator` with keys transformed\n * by `iteratee` and values set by `setter`.\n *\n * @private\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} setter The function to set `accumulator` values.\n * @param {Function} iteratee The iteratee to transform keys.\n * @param {Object} accumulator The initial aggregated object.\n * @returns {Function} Returns `accumulator`.\n */\n function baseAggregator(collection, setter, iteratee, accumulator) {\n baseEach(collection, function(value, key, collection) {\n setter(accumulator, value, iteratee(value), collection);\n });\n return accumulator;\n }\n\n /**\n * The base implementation of `_.assign` without support for multiple sources\n * or `customizer` functions.\n *\n * @private\n * @param {Object} object The destination object.\n * @param {Object} source The source object.\n * @returns {Object} Returns `object`.\n */\n function baseAssign(object, source) {\n return object && copyObject(source, keys(source), object);\n }\n\n /**\n * The base implementation of `_.assignIn` without support for multiple sources\n * or `customizer` functions.\n *\n * @private\n * @param {Object} object The destination object.\n * @param {Object} source The source object.\n * @returns {Object} Returns `object`.\n */\n function baseAssignIn(object, source) {\n return object && copyObject(source, keysIn(source), object);\n }\n\n /**\n * The base implementation of `assignValue` and `assignMergeValue` without\n * value checks.\n *\n * @private\n * @param {Object} object The object to modify.\n * @param {string} key The key of the property to assign.\n * @param {*} value The value to assign.\n */\n function baseAssignValue(object, key, value) {\n if (key == '__proto__' && defineProperty) {\n defineProperty(object, key, {\n 'configurable': true,\n 'enumerable': true,\n 'value': value,\n 'writable': true\n });\n } else {\n object[key] = value;\n }\n }\n\n /**\n * The base implementation of `_.at` without support for individual paths.\n *\n * @private\n * @param {Object} object The object to iterate over.\n * @param {string[]} paths The property paths to pick.\n * @returns {Array} Returns the picked elements.\n */\n function baseAt(object, paths) {\n var index = -1,\n length = paths.length,\n result = Array(length),\n skip = object == null;\n\n while (++index < length) {\n result[index] = skip ? undefined : get(object, paths[index]);\n }\n return result;\n }\n\n /**\n * The base implementation of `_.clamp` which doesn't coerce arguments.\n *\n * @private\n * @param {number} number The number to clamp.\n * @param {number} [lower] The lower bound.\n * @param {number} upper The upper bound.\n * @returns {number} Returns the clamped number.\n */\n function baseClamp(number, lower, upper) {\n if (number === number) {\n if (upper !== undefined) {\n number = number <= upper ? number : upper;\n }\n if (lower !== undefined) {\n number = number >= lower ? number : lower;\n }\n }\n return number;\n }\n\n /**\n * The base implementation of `_.clone` and `_.cloneDeep` which tracks\n * traversed objects.\n *\n * @private\n * @param {*} value The value to clone.\n * @param {boolean} bitmask The bitmask flags.\n * 1 - Deep clone\n * 2 - Flatten inherited properties\n * 4 - Clone symbols\n * @param {Function} [customizer] The function to customize cloning.\n * @param {string} [key] The key of `value`.\n * @param {Object} [object] The parent object of `value`.\n * @param {Object} [stack] Tracks traversed objects and their clone counterparts.\n * @returns {*} Returns the cloned value.\n */\n function baseClone(value, bitmask, customizer, key, object, stack) {\n var result,\n isDeep = bitmask & CLONE_DEEP_FLAG,\n isFlat = bitmask & CLONE_FLAT_FLAG,\n isFull = bitmask & CLONE_SYMBOLS_FLAG;\n\n if (customizer) {\n result = object ? customizer(value, key, object, stack) : customizer(value);\n }\n if (result !== undefined) {\n return result;\n }\n if (!isObject(value)) {\n return value;\n }\n var isArr = isArray(value);\n if (isArr) {\n result = initCloneArray(value);\n if (!isDeep) {\n return copyArray(value, result);\n }\n } else {\n var tag = getTag(value),\n isFunc = tag == funcTag || tag == genTag;\n\n if (isBuffer(value)) {\n return cloneBuffer(value, isDeep);\n }\n if (tag == objectTag || tag == argsTag || (isFunc && !object)) {\n result = (isFlat || isFunc) ? {} : initCloneObject(value);\n if (!isDeep) {\n return isFlat\n ? copySymbolsIn(value, baseAssignIn(result, value))\n : copySymbols(value, baseAssign(result, value));\n }\n } else {\n if (!cloneableTags[tag]) {\n return object ? value : {};\n }\n result = initCloneByTag(value, tag, isDeep);\n }\n }\n // Check for circular references and return its corresponding clone.\n stack || (stack = new Stack);\n var stacked = stack.get(value);\n if (stacked) {\n return stacked;\n }\n stack.set(value, result);\n\n if (isSet(value)) {\n value.forEach(function(subValue) {\n result.add(baseClone(subValue, bitmask, customizer, subValue, value, stack));\n });\n } else if (isMap(value)) {\n value.forEach(function(subValue, key) {\n result.set(key, baseClone(subValue, bitmask, customizer, key, value, stack));\n });\n }\n\n var keysFunc = isFull\n ? (isFlat ? getAllKeysIn : getAllKeys)\n : (isFlat ? keysIn : keys);\n\n var props = isArr ? undefined : keysFunc(value);\n arrayEach(props || value, function(subValue, key) {\n if (props) {\n key = subValue;\n subValue = value[key];\n }\n // Recursively populate clone (susceptible to call stack limits).\n assignValue(result, key, baseClone(subValue, bitmask, customizer, key, value, stack));\n });\n return result;\n }\n\n /**\n * The base implementation of `_.conforms` which doesn't clone `source`.\n *\n * @private\n * @param {Object} source The object of property predicates to conform to.\n * @returns {Function} Returns the new spec function.\n */\n function baseConforms(source) {\n var props = keys(source);\n return function(object) {\n return baseConformsTo(object, source, props);\n };\n }\n\n /**\n * The base implementation of `_.conformsTo` which accepts `props` to check.\n *\n * @private\n * @param {Object} object The object to inspect.\n * @param {Object} source The object of property predicates to conform to.\n * @returns {boolean} Returns `true` if `object` conforms, else `false`.\n */\n function baseConformsTo(object, source, props) {\n var length = props.length;\n if (object == null) {\n return !length;\n }\n object = Object(object);\n while (length--) {\n var key = props[length],\n predicate = source[key],\n value = object[key];\n\n if ((value === undefined && !(key in object)) || !predicate(value)) {\n return false;\n }\n }\n return true;\n }\n\n /**\n * The base implementation of `_.delay` and `_.defer` which accepts `args`\n * to provide to `func`.\n *\n * @private\n * @param {Function} func The function to delay.\n * @param {number} wait The number of milliseconds to delay invocation.\n * @param {Array} args The arguments to provide to `func`.\n * @returns {number|Object} Returns the timer id or timeout object.\n */\n function baseDelay(func, wait, args) {\n if (typeof func != 'function') {\n throw new TypeError(FUNC_ERROR_TEXT);\n }\n return setTimeout(function() { func.apply(undefined, args); }, wait);\n }\n\n /**\n * The base implementation of methods like `_.difference` without support\n * for excluding multiple arrays or iteratee shorthands.\n *\n * @private\n * @param {Array} array The array to inspect.\n * @param {Array} values The values to exclude.\n * @param {Function} [iteratee] The iteratee invoked per element.\n * @param {Function} [comparator] The comparator invoked per element.\n * @returns {Array} Returns the new array of filtered values.\n */\n function baseDifference(array, values, iteratee, comparator) {\n var index = -1,\n includes = arrayIncludes,\n isCommon = true,\n length = array.length,\n result = [],\n valuesLength = values.length;\n\n if (!length) {\n return result;\n }\n if (iteratee) {\n values = arrayMap(values, baseUnary(iteratee));\n }\n if (comparator) {\n includes = arrayIncludesWith;\n isCommon = false;\n }\n else if (values.length >= LARGE_ARRAY_SIZE) {\n includes = cacheHas;\n isCommon = false;\n values = new SetCache(values);\n }\n outer:\n while (++index < length) {\n var value = array[index],\n computed = iteratee == null ? value : iteratee(value);\n\n value = (comparator || value !== 0) ? value : 0;\n if (isCommon && computed === computed) {\n var valuesIndex = valuesLength;\n while (valuesIndex--) {\n if (values[valuesIndex] === computed) {\n continue outer;\n }\n }\n result.push(value);\n }\n else if (!includes(values, computed, comparator)) {\n result.push(value);\n }\n }\n return result;\n }\n\n /**\n * The base implementation of `_.forEach` without support for iteratee shorthands.\n *\n * @private\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} iteratee The function invoked per iteration.\n * @returns {Array|Object} Returns `collection`.\n */\n var baseEach = createBaseEach(baseForOwn);\n\n /**\n * The base implementation of `_.forEachRight` without support for iteratee shorthands.\n *\n * @private\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} iteratee The function invoked per iteration.\n * @returns {Array|Object} Returns `collection`.\n */\n var baseEachRight = createBaseEach(baseForOwnRight, true);\n\n /**\n * The base implementation of `_.every` without support for iteratee shorthands.\n *\n * @private\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} predicate The function invoked per iteration.\n * @returns {boolean} Returns `true` if all elements pass the predicate check,\n * else `false`\n */\n function baseEvery(collection, predicate) {\n var result = true;\n baseEach(collection, function(value, index, collection) {\n result = !!predicate(value, index, collection);\n return result;\n });\n return result;\n }\n\n /**\n * The base implementation of methods like `_.max` and `_.min` which accepts a\n * `comparator` to determine the extremum value.\n *\n * @private\n * @param {Array} array The array to iterate over.\n * @param {Function} iteratee The iteratee invoked per iteration.\n * @param {Function} comparator The comparator used to compare values.\n * @returns {*} Returns the extremum value.\n */\n function baseExtremum(array, iteratee, comparator) {\n var index = -1,\n length = array.length;\n\n while (++index < length) {\n var value = array[index],\n current = iteratee(value);\n\n if (current != null && (computed === undefined\n ? (current === current && !isSymbol(current))\n : comparator(current, computed)\n )) {\n var computed = current,\n result = value;\n }\n }\n return result;\n }\n\n /**\n * The base implementation of `_.fill` without an iteratee call guard.\n *\n * @private\n * @param {Array} array The array to fill.\n * @param {*} value The value to fill `array` with.\n * @param {number} [start=0] The start position.\n * @param {number} [end=array.length] The end position.\n * @returns {Array} Returns `array`.\n */\n function baseFill(array, value, start, end) {\n var length = array.length;\n\n start = toInteger(start);\n if (start < 0) {\n start = -start > length ? 0 : (length + start);\n }\n end = (end === undefined || end > length) ? length : toInteger(end);\n if (end < 0) {\n end += length;\n }\n end = start > end ? 0 : toLength(end);\n while (start < end) {\n array[start++] = value;\n }\n return array;\n }\n\n /**\n * The base implementation of `_.filter` without support for iteratee shorthands.\n *\n * @private\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} predicate The function invoked per iteration.\n * @returns {Array} Returns the new filtered array.\n */\n function baseFilter(collection, predicate) {\n var result = [];\n baseEach(collection, function(value, index, collection) {\n if (predicate(value, index, collection)) {\n result.push(value);\n }\n });\n return result;\n }\n\n /**\n * The base implementation of `_.flatten` with support for restricting flattening.\n *\n * @private\n * @param {Array} array The array to flatten.\n * @param {number} depth The maximum recursion depth.\n * @param {boolean} [predicate=isFlattenable] The function invoked per iteration.\n * @param {boolean} [isStrict] Restrict to values that pass `predicate` checks.\n * @param {Array} [result=[]] The initial result value.\n * @returns {Array} Returns the new flattened array.\n */\n function baseFlatten(array, depth, predicate, isStrict, result) {\n var index = -1,\n length = array.length;\n\n predicate || (predicate = isFlattenable);\n result || (result = []);\n\n while (++index < length) {\n var value = array[index];\n if (depth > 0 && predicate(value)) {\n if (depth > 1) {\n // Recursively flatten arrays (susceptible to call stack limits).\n baseFlatten(value, depth - 1, predicate, isStrict, result);\n } else {\n arrayPush(result, value);\n }\n } else if (!isStrict) {\n result[result.length] = value;\n }\n }\n return result;\n }\n\n /**\n * The base implementation of `baseForOwn` which iterates over `object`\n * properties returned by `keysFunc` and invokes `iteratee` for each property.\n * Iteratee functions may exit iteration early by explicitly returning `false`.\n *\n * @private\n * @param {Object} object The object to iterate over.\n * @param {Function} iteratee The function invoked per iteration.\n * @param {Function} keysFunc The function to get the keys of `object`.\n * @returns {Object} Returns `object`.\n */\n var baseFor = createBaseFor();\n\n /**\n * This function is like `baseFor` except that it iterates over properties\n * in the opposite order.\n *\n * @private\n * @param {Object} object The object to iterate over.\n * @param {Function} iteratee The function invoked per iteration.\n * @param {Function} keysFunc The function to get the keys of `object`.\n * @returns {Object} Returns `object`.\n */\n var baseForRight = createBaseFor(true);\n\n /**\n * The base implementation of `_.forOwn` without support for iteratee shorthands.\n *\n * @private\n * @param {Object} object The object to iterate over.\n * @param {Function} iteratee The function invoked per iteration.\n * @returns {Object} Returns `object`.\n */\n function baseForOwn(object, iteratee) {\n return object && baseFor(object, iteratee, keys);\n }\n\n /**\n * The base implementation of `_.forOwnRight` without support for iteratee shorthands.\n *\n * @private\n * @param {Object} object The object to iterate over.\n * @param {Function} iteratee The function invoked per iteration.\n * @returns {Object} Returns `object`.\n */\n function baseForOwnRight(object, iteratee) {\n return object && baseForRight(object, iteratee, keys);\n }\n\n /**\n * The base implementation of `_.functions` which creates an array of\n * `object` function property names filtered from `props`.\n *\n * @private\n * @param {Object} object The object to inspect.\n * @param {Array} props The property names to filter.\n * @returns {Array} Returns the function names.\n */\n function baseFunctions(object, props) {\n return arrayFilter(props, function(key) {\n return isFunction(object[key]);\n });\n }\n\n /**\n * The base implementation of `_.get` without support for default values.\n *\n * @private\n * @param {Object} object The object to query.\n * @param {Array|string} path The path of the property to get.\n * @returns {*} Returns the resolved value.\n */\n function baseGet(object, path) {\n path = castPath(path, object);\n\n var index = 0,\n length = path.length;\n\n while (object != null && index < length) {\n object = object[toKey(path[index++])];\n }\n return (index && index == length) ? object : undefined;\n }\n\n /**\n * The base implementation of `getAllKeys` and `getAllKeysIn` which uses\n * `keysFunc` and `symbolsFunc` to get the enumerable property names and\n * symbols of `object`.\n *\n * @private\n * @param {Object} object The object to query.\n * @param {Function} keysFunc The function to get the keys of `object`.\n * @param {Function} symbolsFunc The function to get the symbols of `object`.\n * @returns {Array} Returns the array of property names and symbols.\n */\n function baseGetAllKeys(object, keysFunc, symbolsFunc) {\n var result = keysFunc(object);\n return isArray(object) ? result : arrayPush(result, symbolsFunc(object));\n }\n\n /**\n * The base implementation of `getTag` without fallbacks for buggy environments.\n *\n * @private\n * @param {*} value The value to query.\n * @returns {string} Returns the `toStringTag`.\n */\n function baseGetTag(value) {\n if (value == null) {\n return value === undefined ? undefinedTag : nullTag;\n }\n return (symToStringTag && symToStringTag in Object(value))\n ? getRawTag(value)\n : objectToString(value);\n }\n\n /**\n * The base implementation of `_.gt` which doesn't coerce arguments.\n *\n * @private\n * @param {*} value The value to compare.\n * @param {*} other The other value to compare.\n * @returns {boolean} Returns `true` if `value` is greater than `other`,\n * else `false`.\n */\n function baseGt(value, other) {\n return value > other;\n }\n\n /**\n * The base implementation of `_.has` without support for deep paths.\n *\n * @private\n * @param {Object} [object] The object to query.\n * @param {Array|string} key The key to check.\n * @returns {boolean} Returns `true` if `key` exists, else `false`.\n */\n function baseHas(object, key) {\n return object != null && hasOwnProperty.call(object, key);\n }\n\n /**\n * The base implementation of `_.hasIn` without support for deep paths.\n *\n * @private\n * @param {Object} [object] The object to query.\n * @param {Array|string} key The key to check.\n * @returns {boolean} Returns `true` if `key` exists, else `false`.\n */\n function baseHasIn(object, key) {\n return object != null && key in Object(object);\n }\n\n /**\n * The base implementation of `_.inRange` which doesn't coerce arguments.\n *\n * @private\n * @param {number} number The number to check.\n * @param {number} start The start of the range.\n * @param {number} end The end of the range.\n * @returns {boolean} Returns `true` if `number` is in the range, else `false`.\n */\n function baseInRange(number, start, end) {\n return number >= nativeMin(start, end) && number < nativeMax(start, end);\n }\n\n /**\n * The base implementation of methods like `_.intersection`, without support\n * for iteratee shorthands, that accepts an array of arrays to inspect.\n *\n * @private\n * @param {Array} arrays The arrays to inspect.\n * @param {Function} [iteratee] The iteratee invoked per element.\n * @param {Function} [comparator] The comparator invoked per element.\n * @returns {Array} Returns the new array of shared values.\n */\n function baseIntersection(arrays, iteratee, comparator) {\n var includes = comparator ? arrayIncludesWith : arrayIncludes,\n length = arrays[0].length,\n othLength = arrays.length,\n othIndex = othLength,\n caches = Array(othLength),\n maxLength = Infinity,\n result = [];\n\n while (othIndex--) {\n var array = arrays[othIndex];\n if (othIndex && iteratee) {\n array = arrayMap(array, baseUnary(iteratee));\n }\n maxLength = nativeMin(array.length, maxLength);\n caches[othIndex] = !comparator && (iteratee || (length >= 120 && array.length >= 120))\n ? new SetCache(othIndex && array)\n : undefined;\n }\n array = arrays[0];\n\n var index = -1,\n seen = caches[0];\n\n outer:\n while (++index < length && result.length < maxLength) {\n var value = array[index],\n computed = iteratee ? iteratee(value) : value;\n\n value = (comparator || value !== 0) ? value : 0;\n if (!(seen\n ? cacheHas(seen, computed)\n : includes(result, computed, comparator)\n )) {\n othIndex = othLength;\n while (--othIndex) {\n var cache = caches[othIndex];\n if (!(cache\n ? cacheHas(cache, computed)\n : includes(arrays[othIndex], computed, comparator))\n ) {\n continue outer;\n }\n }\n if (seen) {\n seen.push(computed);\n }\n result.push(value);\n }\n }\n return result;\n }\n\n /**\n * The base implementation of `_.invert` and `_.invertBy` which inverts\n * `object` with values transformed by `iteratee` and set by `setter`.\n *\n * @private\n * @param {Object} object The object to iterate over.\n * @param {Function} setter The function to set `accumulator` values.\n * @param {Function} iteratee The iteratee to transform values.\n * @param {Object} accumulator The initial inverted object.\n * @returns {Function} Returns `accumulator`.\n */\n function baseInverter(object, setter, iteratee, accumulator) {\n baseForOwn(object, function(value, key, object) {\n setter(accumulator, iteratee(value), key, object);\n });\n return accumulator;\n }\n\n /**\n * The base implementation of `_.invoke` without support for individual\n * method arguments.\n *\n * @private\n * @param {Object} object The object to query.\n * @param {Array|string} path The path of the method to invoke.\n * @param {Array} args The arguments to invoke the method with.\n * @returns {*} Returns the result of the invoked method.\n */\n function baseInvoke(object, path, args) {\n path = castPath(path, object);\n object = parent(object, path);\n var func = object == null ? object : object[toKey(last(path))];\n return func == null ? undefined : apply(func, object, args);\n }\n\n /**\n * The base implementation of `_.isArguments`.\n *\n * @private\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is an `arguments` object,\n */\n function baseIsArguments(value) {\n return isObjectLike(value) && baseGetTag(value) == argsTag;\n }\n\n /**\n * The base implementation of `_.isArrayBuffer` without Node.js optimizations.\n *\n * @private\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is an array buffer, else `false`.\n */\n function baseIsArrayBuffer(value) {\n return isObjectLike(value) && baseGetTag(value) == arrayBufferTag;\n }\n\n /**\n * The base implementation of `_.isDate` without Node.js optimizations.\n *\n * @private\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a date object, else `false`.\n */\n function baseIsDate(value) {\n return isObjectLike(value) && baseGetTag(value) == dateTag;\n }\n\n /**\n * The base implementation of `_.isEqual` which supports partial comparisons\n * and tracks traversed objects.\n *\n * @private\n * @param {*} value The value to compare.\n * @param {*} other The other value to compare.\n * @param {boolean} bitmask The bitmask flags.\n * 1 - Unordered comparison\n * 2 - Partial comparison\n * @param {Function} [customizer] The function to customize comparisons.\n * @param {Object} [stack] Tracks traversed `value` and `other` objects.\n * @returns {boolean} Returns `true` if the values are equivalent, else `false`.\n */\n function baseIsEqual(value, other, bitmask, customizer, stack) {\n if (value === other) {\n return true;\n }\n if (value == null || other == null || (!isObjectLike(value) && !isObjectLike(other))) {\n return value !== value && other !== other;\n }\n return baseIsEqualDeep(value, other, bitmask, customizer, baseIsEqual, stack);\n }\n\n /**\n * A specialized version of `baseIsEqual` for arrays and objects which performs\n * deep comparisons and tracks traversed objects enabling objects with circular\n * references to be compared.\n *\n * @private\n * @param {Object} object The object to compare.\n * @param {Object} other The other object to compare.\n * @param {number} bitmask The bitmask flags. See `baseIsEqual` for more details.\n * @param {Function} customizer The function to customize comparisons.\n * @param {Function} equalFunc The function to determine equivalents of values.\n * @param {Object} [stack] Tracks traversed `object` and `other` objects.\n * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.\n */\n function baseIsEqualDeep(object, other, bitmask, customizer, equalFunc, stack) {\n var objIsArr = isArray(object),\n othIsArr = isArray(other),\n objTag = objIsArr ? arrayTag : getTag(object),\n othTag = othIsArr ? arrayTag : getTag(other);\n\n objTag = objTag == argsTag ? objectTag : objTag;\n othTag = othTag == argsTag ? objectTag : othTag;\n\n var objIsObj = objTag == objectTag,\n othIsObj = othTag == objectTag,\n isSameTag = objTag == othTag;\n\n if (isSameTag && isBuffer(object)) {\n if (!isBuffer(other)) {\n return false;\n }\n objIsArr = true;\n objIsObj = false;\n }\n if (isSameTag && !objIsObj) {\n stack || (stack = new Stack);\n return (objIsArr || isTypedArray(object))\n ? equalArrays(object, other, bitmask, customizer, equalFunc, stack)\n : equalByTag(object, other, objTag, bitmask, customizer, equalFunc, stack);\n }\n if (!(bitmask & COMPARE_PARTIAL_FLAG)) {\n var objIsWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),\n othIsWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');\n\n if (objIsWrapped || othIsWrapped) {\n var objUnwrapped = objIsWrapped ? object.value() : object,\n othUnwrapped = othIsWrapped ? other.value() : other;\n\n stack || (stack = new Stack);\n return equalFunc(objUnwrapped, othUnwrapped, bitmask, customizer, stack);\n }\n }\n if (!isSameTag) {\n return false;\n }\n stack || (stack = new Stack);\n return equalObjects(object, other, bitmask, customizer, equalFunc, stack);\n }\n\n /**\n * The base implementation of `_.isMap` without Node.js optimizations.\n *\n * @private\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a map, else `false`.\n */\n function baseIsMap(value) {\n return isObjectLike(value) && getTag(value) == mapTag;\n }\n\n /**\n * The base implementation of `_.isMatch` without support for iteratee shorthands.\n *\n * @private\n * @param {Object} object The object to inspect.\n * @param {Object} source The object of property values to match.\n * @param {Array} matchData The property names, values, and compare flags to match.\n * @param {Function} [customizer] The function to customize comparisons.\n * @returns {boolean} Returns `true` if `object` is a match, else `false`.\n */\n function baseIsMatch(object, source, matchData, customizer) {\n var index = matchData.length,\n length = index,\n noCustomizer = !customizer;\n\n if (object == null) {\n return !length;\n }\n object = Object(object);\n while (index--) {\n var data = matchData[index];\n if ((noCustomizer && data[2])\n ? data[1] !== object[data[0]]\n : !(data[0] in object)\n ) {\n return false;\n }\n }\n while (++index < length) {\n data = matchData[index];\n var key = data[0],\n objValue = object[key],\n srcValue = data[1];\n\n if (noCustomizer && data[2]) {\n if (objValue === undefined && !(key in object)) {\n return false;\n }\n } else {\n var stack = new Stack;\n if (customizer) {\n var result = customizer(objValue, srcValue, key, object, source, stack);\n }\n if (!(result === undefined\n ? baseIsEqual(srcValue, objValue, COMPARE_PARTIAL_FLAG | COMPARE_UNORDERED_FLAG, customizer, stack)\n : result\n )) {\n return false;\n }\n }\n }\n return true;\n }\n\n /**\n * The base implementation of `_.isNative` without bad shim checks.\n *\n * @private\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a native function,\n * else `false`.\n */\n function baseIsNative(value) {\n if (!isObject(value) || isMasked(value)) {\n return false;\n }\n var pattern = isFunction(value) ? reIsNative : reIsHostCtor;\n return pattern.test(toSource(value));\n }\n\n /**\n * The base implementation of `_.isRegExp` without Node.js optimizations.\n *\n * @private\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a regexp, else `false`.\n */\n function baseIsRegExp(value) {\n return isObjectLike(value) && baseGetTag(value) == regexpTag;\n }\n\n /**\n * The base implementation of `_.isSet` without Node.js optimizations.\n *\n * @private\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a set, else `false`.\n */\n function baseIsSet(value) {\n return isObjectLike(value) && getTag(value) == setTag;\n }\n\n /**\n * The base implementation of `_.isTypedArray` without Node.js optimizations.\n *\n * @private\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a typed array, else `false`.\n */\n function baseIsTypedArray(value) {\n return isObjectLike(value) &&\n isLength(value.length) && !!typedArrayTags[baseGetTag(value)];\n }\n\n /**\n * The base implementation of `_.iteratee`.\n *\n * @private\n * @param {*} [value=_.identity] The value to convert to an iteratee.\n * @returns {Function} Returns the iteratee.\n */\n function baseIteratee(value) {\n // Don't store the `typeof` result in a variable to avoid a JIT bug in Safari 9.\n // See https://bugs.webkit.org/show_bug.cgi?id=156034 for more details.\n if (typeof value == 'function') {\n return value;\n }\n if (value == null) {\n return identity;\n }\n if (typeof value == 'object') {\n return isArray(value)\n ? baseMatchesProperty(value[0], value[1])\n : baseMatches(value);\n }\n return property(value);\n }\n\n /**\n * The base implementation of `_.keys` which doesn't treat sparse arrays as dense.\n *\n * @private\n * @param {Object} object The object to query.\n * @returns {Array} Returns the array of property names.\n */\n function baseKeys(object) {\n if (!isPrototype(object)) {\n return nativeKeys(object);\n }\n var result = [];\n for (var key in Object(object)) {\n if (hasOwnProperty.call(object, key) && key != 'constructor') {\n result.push(key);\n }\n }\n return result;\n }\n\n /**\n * The base implementation of `_.keysIn` which doesn't treat sparse arrays as dense.\n *\n * @private\n * @param {Object} object The object to query.\n * @returns {Array} Returns the array of property names.\n */\n function baseKeysIn(object) {\n if (!isObject(object)) {\n return nativeKeysIn(object);\n }\n var isProto = isPrototype(object),\n result = [];\n\n for (var key in object) {\n if (!(key == 'constructor' && (isProto || !hasOwnProperty.call(object, key)))) {\n result.push(key);\n }\n }\n return result;\n }\n\n /**\n * The base implementation of `_.lt` which doesn't coerce arguments.\n *\n * @private\n * @param {*} value The value to compare.\n * @param {*} other The other value to compare.\n * @returns {boolean} Returns `true` if `value` is less than `other`,\n * else `false`.\n */\n function baseLt(value, other) {\n return value < other;\n }\n\n /**\n * The base implementation of `_.map` without support for iteratee shorthands.\n *\n * @private\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} iteratee The function invoked per iteration.\n * @returns {Array} Returns the new mapped array.\n */\n function baseMap(collection, iteratee) {\n var index = -1,\n result = isArrayLike(collection) ? Array(collection.length) : [];\n\n baseEach(collection, function(value, key, collection) {\n result[++index] = iteratee(value, key, collection);\n });\n return result;\n }\n\n /**\n * The base implementation of `_.matches` which doesn't clone `source`.\n *\n * @private\n * @param {Object} source The object of property values to match.\n * @returns {Function} Returns the new spec function.\n */\n function baseMatches(source) {\n var matchData = getMatchData(source);\n if (matchData.length == 1 && matchData[0][2]) {\n return matchesStrictComparable(matchData[0][0], matchData[0][1]);\n }\n return function(object) {\n return object === source || baseIsMatch(object, source, matchData);\n };\n }\n\n /**\n * The base implementation of `_.matchesProperty` which doesn't clone `srcValue`.\n *\n * @private\n * @param {string} path The path of the property to get.\n * @param {*} srcValue The value to match.\n * @returns {Function} Returns the new spec function.\n */\n function baseMatchesProperty(path, srcValue) {\n if (isKey(path) && isStrictComparable(srcValue)) {\n return matchesStrictComparable(toKey(path), srcValue);\n }\n return function(object) {\n var objValue = get(object, path);\n return (objValue === undefined && objValue === srcValue)\n ? hasIn(object, path)\n : baseIsEqual(srcValue, objValue, COMPARE_PARTIAL_FLAG | COMPARE_UNORDERED_FLAG);\n };\n }\n\n /**\n * The base implementation of `_.merge` without support for multiple sources.\n *\n * @private\n * @param {Object} object The destination object.\n * @param {Object} source The source object.\n * @param {number} srcIndex The index of `source`.\n * @param {Function} [customizer] The function to customize merged values.\n * @param {Object} [stack] Tracks traversed source values and their merged\n * counterparts.\n */\n function baseMerge(object, source, srcIndex, customizer, stack) {\n if (object === source) {\n return;\n }\n baseFor(source, function(srcValue, key) {\n stack || (stack = new Stack);\n if (isObject(srcValue)) {\n baseMergeDeep(object, source, key, srcIndex, baseMerge, customizer, stack);\n }\n else {\n var newValue = customizer\n ? customizer(safeGet(object, key), srcValue, (key + ''), object, source, stack)\n : undefined;\n\n if (newValue === undefined) {\n newValue = srcValue;\n }\n assignMergeValue(object, key, newValue);\n }\n }, keysIn);\n }\n\n /**\n * A specialized version of `baseMerge` for arrays and objects which performs\n * deep merges and tracks traversed objects enabling objects with circular\n * references to be merged.\n *\n * @private\n * @param {Object} object The destination object.\n * @param {Object} source The source object.\n * @param {string} key The key of the value to merge.\n * @param {number} srcIndex The index of `source`.\n * @param {Function} mergeFunc The function to merge values.\n * @param {Function} [customizer] The function to customize assigned values.\n * @param {Object} [stack] Tracks traversed source values and their merged\n * counterparts.\n */\n function baseMergeDeep(object, source, key, srcIndex, mergeFunc, customizer, stack) {\n var objValue = safeGet(object, key),\n srcValue = safeGet(source, key),\n stacked = stack.get(srcValue);\n\n if (stacked) {\n assignMergeValue(object, key, stacked);\n return;\n }\n var newValue = customizer\n ? customizer(objValue, srcValue, (key + ''), object, source, stack)\n : undefined;\n\n var isCommon = newValue === undefined;\n\n if (isCommon) {\n var isArr = isArray(srcValue),\n isBuff = !isArr && isBuffer(srcValue),\n isTyped = !isArr && !isBuff && isTypedArray(srcValue);\n\n newValue = srcValue;\n if (isArr || isBuff || isTyped) {\n if (isArray(objValue)) {\n newValue = objValue;\n }\n else if (isArrayLikeObject(objValue)) {\n newValue = copyArray(objValue);\n }\n else if (isBuff) {\n isCommon = false;\n newValue = cloneBuffer(srcValue, true);\n }\n else if (isTyped) {\n isCommon = false;\n newValue = cloneTypedArray(srcValue, true);\n }\n else {\n newValue = [];\n }\n }\n else if (isPlainObject(srcValue) || isArguments(srcValue)) {\n newValue = objValue;\n if (isArguments(objValue)) {\n newValue = toPlainObject(objValue);\n }\n else if (!isObject(objValue) || isFunction(objValue)) {\n newValue = initCloneObject(srcValue);\n }\n }\n else {\n isCommon = false;\n }\n }\n if (isCommon) {\n // Recursively merge objects and arrays (susceptible to call stack limits).\n stack.set(srcValue, newValue);\n mergeFunc(newValue, srcValue, srcIndex, customizer, stack);\n stack['delete'](srcValue);\n }\n assignMergeValue(object, key, newValue);\n }\n\n /**\n * The base implementation of `_.nth` which doesn't coerce arguments.\n *\n * @private\n * @param {Array} array The array to query.\n * @param {number} n The index of the element to return.\n * @returns {*} Returns the nth element of `array`.\n */\n function baseNth(array, n) {\n var length = array.length;\n if (!length) {\n return;\n }\n n += n < 0 ? length : 0;\n return isIndex(n, length) ? array[n] : undefined;\n }\n\n /**\n * The base implementation of `_.orderBy` without param guards.\n *\n * @private\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.\n * @param {string[]} orders The sort orders of `iteratees`.\n * @returns {Array} Returns the new sorted array.\n */\n function baseOrderBy(collection, iteratees, orders) {\n var index = -1;\n iteratees = arrayMap(iteratees.length ? iteratees : [identity], baseUnary(getIteratee()));\n\n var result = baseMap(collection, function(value, key, collection) {\n var criteria = arrayMap(iteratees, function(iteratee) {\n return iteratee(value);\n });\n return { 'criteria': criteria, 'index': ++index, 'value': value };\n });\n\n return baseSortBy(result, function(object, other) {\n return compareMultiple(object, other, orders);\n });\n }\n\n /**\n * The base implementation of `_.pick` without support for individual\n * property identifiers.\n *\n * @private\n * @param {Object} object The source object.\n * @param {string[]} paths The property paths to pick.\n * @returns {Object} Returns the new object.\n */\n function basePick(object, paths) {\n return basePickBy(object, paths, function(value, path) {\n return hasIn(object, path);\n });\n }\n\n /**\n * The base implementation of `_.pickBy` without support for iteratee shorthands.\n *\n * @private\n * @param {Object} object The source object.\n * @param {string[]} paths The property paths to pick.\n * @param {Function} predicate The function invoked per property.\n * @returns {Object} Returns the new object.\n */\n function basePickBy(object, paths, predicate) {\n var index = -1,\n length = paths.length,\n result = {};\n\n while (++index < length) {\n var path = paths[index],\n value = baseGet(object, path);\n\n if (predicate(value, path)) {\n baseSet(result, castPath(path, object), value);\n }\n }\n return result;\n }\n\n /**\n * A specialized version of `baseProperty` which supports deep paths.\n *\n * @private\n * @param {Array|string} path The path of the property to get.\n * @returns {Function} Returns the new accessor function.\n */\n function basePropertyDeep(path) {\n return function(object) {\n return baseGet(object, path);\n };\n }\n\n /**\n * The base implementation of `_.pullAllBy` without support for iteratee\n * shorthands.\n *\n * @private\n * @param {Array} array The array to modify.\n * @param {Array} values The values to remove.\n * @param {Function} [iteratee] The iteratee invoked per element.\n * @param {Function} [comparator] The comparator invoked per element.\n * @returns {Array} Returns `array`.\n */\n function basePullAll(array, values, iteratee, comparator) {\n var indexOf = comparator ? baseIndexOfWith : baseIndexOf,\n index = -1,\n length = values.length,\n seen = array;\n\n if (array === values) {\n values = copyArray(values);\n }\n if (iteratee) {\n seen = arrayMap(array, baseUnary(iteratee));\n }\n while (++index < length) {\n var fromIndex = 0,\n value = values[index],\n computed = iteratee ? iteratee(value) : value;\n\n while ((fromIndex = indexOf(seen, computed, fromIndex, comparator)) > -1) {\n if (seen !== array) {\n splice.call(seen, fromIndex, 1);\n }\n splice.call(array, fromIndex, 1);\n }\n }\n return array;\n }\n\n /**\n * The base implementation of `_.pullAt` without support for individual\n * indexes or capturing the removed elements.\n *\n * @private\n * @param {Array} array The array to modify.\n * @param {number[]} indexes The indexes of elements to remove.\n * @returns {Array} Returns `array`.\n */\n function basePullAt(array, indexes) {\n var length = array ? indexes.length : 0,\n lastIndex = length - 1;\n\n while (length--) {\n var index = indexes[length];\n if (length == lastIndex || index !== previous) {\n var previous = index;\n if (isIndex(index)) {\n splice.call(array, index, 1);\n } else {\n baseUnset(array, index);\n }\n }\n }\n return array;\n }\n\n /**\n * The base implementation of `_.random` without support for returning\n * floating-point numbers.\n *\n * @private\n * @param {number} lower The lower bound.\n * @param {number} upper The upper bound.\n * @returns {number} Returns the random number.\n */\n function baseRandom(lower, upper) {\n return lower + nativeFloor(nativeRandom() * (upper - lower + 1));\n }\n\n /**\n * The base implementation of `_.range` and `_.rangeRight` which doesn't\n * coerce arguments.\n *\n * @private\n * @param {number} start The start of the range.\n * @param {number} end The end of the range.\n * @param {number} step The value to increment or decrement by.\n * @param {boolean} [fromRight] Specify iterating from right to left.\n * @returns {Array} Returns the range of numbers.\n */\n function baseRange(start, end, step, fromRight) {\n var index = -1,\n length = nativeMax(nativeCeil((end - start) / (step || 1)), 0),\n result = Array(length);\n\n while (length--) {\n result[fromRight ? length : ++index] = start;\n start += step;\n }\n return result;\n }\n\n /**\n * The base implementation of `_.repeat` which doesn't coerce arguments.\n *\n * @private\n * @param {string} string The string to repeat.\n * @param {number} n The number of times to repeat the string.\n * @returns {string} Returns the repeated string.\n */\n function baseRepeat(string, n) {\n var result = '';\n if (!string || n < 1 || n > MAX_SAFE_INTEGER) {\n return result;\n }\n // Leverage the exponentiation by squaring algorithm for a faster repeat.\n // See https://en.wikipedia.org/wiki/Exponentiation_by_squaring for more details.\n do {\n if (n % 2) {\n result += string;\n }\n n = nativeFloor(n / 2);\n if (n) {\n string += string;\n }\n } while (n);\n\n return result;\n }\n\n /**\n * The base implementation of `_.rest` which doesn't validate or coerce arguments.\n *\n * @private\n * @param {Function} func The function to apply a rest parameter to.\n * @param {number} [start=func.length-1] The start position of the rest parameter.\n * @returns {Function} Returns the new function.\n */\n function baseRest(func, start) {\n return setToString(overRest(func, start, identity), func + '');\n }\n\n /**\n * The base implementation of `_.sample`.\n *\n * @private\n * @param {Array|Object} collection The collection to sample.\n * @returns {*} Returns the random element.\n */\n function baseSample(collection) {\n return arraySample(values(collection));\n }\n\n /**\n * The base implementation of `_.sampleSize` without param guards.\n *\n * @private\n * @param {Array|Object} collection The collection to sample.\n * @param {number} n The number of elements to sample.\n * @returns {Array} Returns the random elements.\n */\n function baseSampleSize(collection, n) {\n var array = values(collection);\n return shuffleSelf(array, baseClamp(n, 0, array.length));\n }\n\n /**\n * The base implementation of `_.set`.\n *\n * @private\n * @param {Object} object The object to modify.\n * @param {Array|string} path The path of the property to set.\n * @param {*} value The value to set.\n * @param {Function} [customizer] The function to customize path creation.\n * @returns {Object} Returns `object`.\n */\n function baseSet(object, path, value, customizer) {\n if (!isObject(object)) {\n return object;\n }\n path = castPath(path, object);\n\n var index = -1,\n length = path.length,\n lastIndex = length - 1,\n nested = object;\n\n while (nested != null && ++index < length) {\n var key = toKey(path[index]),\n newValue = value;\n\n if (index != lastIndex) {\n var objValue = nested[key];\n newValue = customizer ? customizer(objValue, key, nested) : undefined;\n if (newValue === undefined) {\n newValue = isObject(objValue)\n ? objValue\n : (isIndex(path[index + 1]) ? [] : {});\n }\n }\n assignValue(nested, key, newValue);\n nested = nested[key];\n }\n return object;\n }\n\n /**\n * The base implementation of `setData` without support for hot loop shorting.\n *\n * @private\n * @param {Function} func The function to associate metadata with.\n * @param {*} data The metadata.\n * @returns {Function} Returns `func`.\n */\n var baseSetData = !metaMap ? identity : function(func, data) {\n metaMap.set(func, data);\n return func;\n };\n\n /**\n * The base implementation of `setToString` without support for hot loop shorting.\n *\n * @private\n * @param {Function} func The function to modify.\n * @param {Function} string The `toString` result.\n * @returns {Function} Returns `func`.\n */\n var baseSetToString = !defineProperty ? identity : function(func, string) {\n return defineProperty(func, 'toString', {\n 'configurable': true,\n 'enumerable': false,\n 'value': constant(string),\n 'writable': true\n });\n };\n\n /**\n * The base implementation of `_.shuffle`.\n *\n * @private\n * @param {Array|Object} collection The collection to shuffle.\n * @returns {Array} Returns the new shuffled array.\n */\n function baseShuffle(collection) {\n return shuffleSelf(values(collection));\n }\n\n /**\n * The base implementation of `_.slice` without an iteratee call guard.\n *\n * @private\n * @param {Array} array The array to slice.\n * @param {number} [start=0] The start position.\n * @param {number} [end=array.length] The end position.\n * @returns {Array} Returns the slice of `array`.\n */\n function baseSlice(array, start, end) {\n var index = -1,\n length = array.length;\n\n if (start < 0) {\n start = -start > length ? 0 : (length + start);\n }\n end = end > length ? length : end;\n if (end < 0) {\n end += length;\n }\n length = start > end ? 0 : ((end - start) >>> 0);\n start >>>= 0;\n\n var result = Array(length);\n while (++index < length) {\n result[index] = array[index + start];\n }\n return result;\n }\n\n /**\n * The base implementation of `_.some` without support for iteratee shorthands.\n *\n * @private\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} predicate The function invoked per iteration.\n * @returns {boolean} Returns `true` if any element passes the predicate check,\n * else `false`.\n */\n function baseSome(collection, predicate) {\n var result;\n\n baseEach(collection, function(value, index, collection) {\n result = predicate(value, index, collection);\n return !result;\n });\n return !!result;\n }\n\n /**\n * The base implementation of `_.sortedIndex` and `_.sortedLastIndex` which\n * performs a binary search of `array` to determine the index at which `value`\n * should be inserted into `array` in order to maintain its sort order.\n *\n * @private\n * @param {Array} array The sorted array to inspect.\n * @param {*} value The value to evaluate.\n * @param {boolean} [retHighest] Specify returning the highest qualified index.\n * @returns {number} Returns the index at which `value` should be inserted\n * into `array`.\n */\n function baseSortedIndex(array, value, retHighest) {\n var low = 0,\n high = array == null ? low : array.length;\n\n if (typeof value == 'number' && value === value && high <= HALF_MAX_ARRAY_LENGTH) {\n while (low < high) {\n var mid = (low + high) >>> 1,\n computed = array[mid];\n\n if (computed !== null && !isSymbol(computed) &&\n (retHighest ? (computed <= value) : (computed < value))) {\n low = mid + 1;\n } else {\n high = mid;\n }\n }\n return high;\n }\n return baseSortedIndexBy(array, value, identity, retHighest);\n }\n\n /**\n * The base implementation of `_.sortedIndexBy` and `_.sortedLastIndexBy`\n * which invokes `iteratee` for `value` and each element of `array` to compute\n * their sort ranking. The iteratee is invoked with one argument; (value).\n *\n * @private\n * @param {Array} array The sorted array to inspect.\n * @param {*} value The value to evaluate.\n * @param {Function} iteratee The iteratee invoked per element.\n * @param {boolean} [retHighest] Specify returning the highest qualified index.\n * @returns {number} Returns the index at which `value` should be inserted\n * into `array`.\n */\n function baseSortedIndexBy(array, value, iteratee, retHighest) {\n value = iteratee(value);\n\n var low = 0,\n high = array == null ? 0 : array.length,\n valIsNaN = value !== value,\n valIsNull = value === null,\n valIsSymbol = isSymbol(value),\n valIsUndefined = value === undefined;\n\n while (low < high) {\n var mid = nativeFloor((low + high) / 2),\n computed = iteratee(array[mid]),\n othIsDefined = computed !== undefined,\n othIsNull = computed === null,\n othIsReflexive = computed === computed,\n othIsSymbol = isSymbol(computed);\n\n if (valIsNaN) {\n var setLow = retHighest || othIsReflexive;\n } else if (valIsUndefined) {\n setLow = othIsReflexive && (retHighest || othIsDefined);\n } else if (valIsNull) {\n setLow = othIsReflexive && othIsDefined && (retHighest || !othIsNull);\n } else if (valIsSymbol) {\n setLow = othIsReflexive && othIsDefined && !othIsNull && (retHighest || !othIsSymbol);\n } else if (othIsNull || othIsSymbol) {\n setLow = false;\n } else {\n setLow = retHighest ? (computed <= value) : (computed < value);\n }\n if (setLow) {\n low = mid + 1;\n } else {\n high = mid;\n }\n }\n return nativeMin(high, MAX_ARRAY_INDEX);\n }\n\n /**\n * The base implementation of `_.sortedUniq` and `_.sortedUniqBy` without\n * support for iteratee shorthands.\n *\n * @private\n * @param {Array} array The array to inspect.\n * @param {Function} [iteratee] The iteratee invoked per element.\n * @returns {Array} Returns the new duplicate free array.\n */\n function baseSortedUniq(array, iteratee) {\n var index = -1,\n length = array.length,\n resIndex = 0,\n result = [];\n\n while (++index < length) {\n var value = array[index],\n computed = iteratee ? iteratee(value) : value;\n\n if (!index || !eq(computed, seen)) {\n var seen = computed;\n result[resIndex++] = value === 0 ? 0 : value;\n }\n }\n return result;\n }\n\n /**\n * The base implementation of `_.toNumber` which doesn't ensure correct\n * conversions of binary, hexadecimal, or octal string values.\n *\n * @private\n * @param {*} value The value to process.\n * @returns {number} Returns the number.\n */\n function baseToNumber(value) {\n if (typeof value == 'number') {\n return value;\n }\n if (isSymbol(value)) {\n return NAN;\n }\n return +value;\n }\n\n /**\n * The base implementation of `_.toString` which doesn't convert nullish\n * values to empty strings.\n *\n * @private\n * @param {*} value The value to process.\n * @returns {string} Returns the string.\n */\n function baseToString(value) {\n // Exit early for strings to avoid a performance hit in some environments.\n if (typeof value == 'string') {\n return value;\n }\n if (isArray(value)) {\n // Recursively convert values (susceptible to call stack limits).\n return arrayMap(value, baseToString) + '';\n }\n if (isSymbol(value)) {\n return symbolToString ? symbolToString.call(value) : '';\n }\n var result = (value + '');\n return (result == '0' && (1 / value) == -INFINITY) ? '-0' : result;\n }\n\n /**\n * The base implementation of `_.uniqBy` without support for iteratee shorthands.\n *\n * @private\n * @param {Array} array The array to inspect.\n * @param {Function} [iteratee] The iteratee invoked per element.\n * @param {Function} [comparator] The comparator invoked per element.\n * @returns {Array} Returns the new duplicate free array.\n */\n function baseUniq(array, iteratee, comparator) {\n var index = -1,\n includes = arrayIncludes,\n length = array.length,\n isCommon = true,\n result = [],\n seen = result;\n\n if (comparator) {\n isCommon = false;\n includes = arrayIncludesWith;\n }\n else if (length >= LARGE_ARRAY_SIZE) {\n var set = iteratee ? null : createSet(array);\n if (set) {\n return setToArray(set);\n }\n isCommon = false;\n includes = cacheHas;\n seen = new SetCache;\n }\n else {\n seen = iteratee ? [] : result;\n }\n outer:\n while (++index < length) {\n var value = array[index],\n computed = iteratee ? iteratee(value) : value;\n\n value = (comparator || value !== 0) ? value : 0;\n if (isCommon && computed === computed) {\n var seenIndex = seen.length;\n while (seenIndex--) {\n if (seen[seenIndex] === computed) {\n continue outer;\n }\n }\n if (iteratee) {\n seen.push(computed);\n }\n result.push(value);\n }\n else if (!includes(seen, computed, comparator)) {\n if (seen !== result) {\n seen.push(computed);\n }\n result.push(value);\n }\n }\n return result;\n }\n\n /**\n * The base implementation of `_.unset`.\n *\n * @private\n * @param {Object} object The object to modify.\n * @param {Array|string} path The property path to unset.\n * @returns {boolean} Returns `true` if the property is deleted, else `false`.\n */\n function baseUnset(object, path) {\n path = castPath(path, object);\n object = parent(object, path);\n return object == null || delete object[toKey(last(path))];\n }\n\n /**\n * The base implementation of `_.update`.\n *\n * @private\n * @param {Object} object The object to modify.\n * @param {Array|string} path The path of the property to update.\n * @param {Function} updater The function to produce the updated value.\n * @param {Function} [customizer] The function to customize path creation.\n * @returns {Object} Returns `object`.\n */\n function baseUpdate(object, path, updater, customizer) {\n return baseSet(object, path, updater(baseGet(object, path)), customizer);\n }\n\n /**\n * The base implementation of methods like `_.dropWhile` and `_.takeWhile`\n * without support for iteratee shorthands.\n *\n * @private\n * @param {Array} array The array to query.\n * @param {Function} predicate The function invoked per iteration.\n * @param {boolean} [isDrop] Specify dropping elements instead of taking them.\n * @param {boolean} [fromRight] Specify iterating from right to left.\n * @returns {Array} Returns the slice of `array`.\n */\n function baseWhile(array, predicate, isDrop, fromRight) {\n var length = array.length,\n index = fromRight ? length : -1;\n\n while ((fromRight ? index-- : ++index < length) &&\n predicate(array[index], index, array)) {}\n\n return isDrop\n ? baseSlice(array, (fromRight ? 0 : index), (fromRight ? index + 1 : length))\n : baseSlice(array, (fromRight ? index + 1 : 0), (fromRight ? length : index));\n }\n\n /**\n * The base implementation of `wrapperValue` which returns the result of\n * performing a sequence of actions on the unwrapped `value`, where each\n * successive action is supplied the return value of the previous.\n *\n * @private\n * @param {*} value The unwrapped value.\n * @param {Array} actions Actions to perform to resolve the unwrapped value.\n * @returns {*} Returns the resolved value.\n */\n function baseWrapperValue(value, actions) {\n var result = value;\n if (result instanceof LazyWrapper) {\n result = result.value();\n }\n return arrayReduce(actions, function(result, action) {\n return action.func.apply(action.thisArg, arrayPush([result], action.args));\n }, result);\n }\n\n /**\n * The base implementation of methods like `_.xor`, without support for\n * iteratee shorthands, that accepts an array of arrays to inspect.\n *\n * @private\n * @param {Array} arrays The arrays to inspect.\n * @param {Function} [iteratee] The iteratee invoked per element.\n * @param {Function} [comparator] The comparator invoked per element.\n * @returns {Array} Returns the new array of values.\n */\n function baseXor(arrays, iteratee, comparator) {\n var length = arrays.length;\n if (length < 2) {\n return length ? baseUniq(arrays[0]) : [];\n }\n var index = -1,\n result = Array(length);\n\n while (++index < length) {\n var array = arrays[index],\n othIndex = -1;\n\n while (++othIndex < length) {\n if (othIndex != index) {\n result[index] = baseDifference(result[index] || array, arrays[othIndex], iteratee, comparator);\n }\n }\n }\n return baseUniq(baseFlatten(result, 1), iteratee, comparator);\n }\n\n /**\n * This base implementation of `_.zipObject` which assigns values using `assignFunc`.\n *\n * @private\n * @param {Array} props The property identifiers.\n * @param {Array} values The property values.\n * @param {Function} assignFunc The function to assign values.\n * @returns {Object} Returns the new object.\n */\n function baseZipObject(props, values, assignFunc) {\n var index = -1,\n length = props.length,\n valsLength = values.length,\n result = {};\n\n while (++index < length) {\n var value = index < valsLength ? values[index] : undefined;\n assignFunc(result, props[index], value);\n }\n return result;\n }\n\n /**\n * Casts `value` to an empty array if it's not an array like object.\n *\n * @private\n * @param {*} value The value to inspect.\n * @returns {Array|Object} Returns the cast array-like object.\n */\n function castArrayLikeObject(value) {\n return isArrayLikeObject(value) ? value : [];\n }\n\n /**\n * Casts `value` to `identity` if it's not a function.\n *\n * @private\n * @param {*} value The value to inspect.\n * @returns {Function} Returns cast function.\n */\n function castFunction(value) {\n return typeof value == 'function' ? value : identity;\n }\n\n /**\n * Casts `value` to a path array if it's not one.\n *\n * @private\n * @param {*} value The value to inspect.\n * @param {Object} [object] The object to query keys on.\n * @returns {Array} Returns the cast property path array.\n */\n function castPath(value, object) {\n if (isArray(value)) {\n return value;\n }\n return isKey(value, object) ? [value] : stringToPath(toString(value));\n }\n\n /**\n * A `baseRest` alias which can be replaced with `identity` by module\n * replacement plugins.\n *\n * @private\n * @type {Function}\n * @param {Function} func The function to apply a rest parameter to.\n * @returns {Function} Returns the new function.\n */\n var castRest = baseRest;\n\n /**\n * Casts `array` to a slice if it's needed.\n *\n * @private\n * @param {Array} array The array to inspect.\n * @param {number} start The start position.\n * @param {number} [end=array.length] The end position.\n * @returns {Array} Returns the cast slice.\n */\n function castSlice(array, start, end) {\n var length = array.length;\n end = end === undefined ? length : end;\n return (!start && end >= length) ? array : baseSlice(array, start, end);\n }\n\n /**\n * A simple wrapper around the global [`clearTimeout`](https://mdn.io/clearTimeout).\n *\n * @private\n * @param {number|Object} id The timer id or timeout object of the timer to clear.\n */\n var clearTimeout = ctxClearTimeout || function(id) {\n return root.clearTimeout(id);\n };\n\n /**\n * Creates a clone of `buffer`.\n *\n * @private\n * @param {Buffer} buffer The buffer to clone.\n * @param {boolean} [isDeep] Specify a deep clone.\n * @returns {Buffer} Returns the cloned buffer.\n */\n function cloneBuffer(buffer, isDeep) {\n if (isDeep) {\n return buffer.slice();\n }\n var length = buffer.length,\n result = allocUnsafe ? allocUnsafe(length) : new buffer.constructor(length);\n\n buffer.copy(result);\n return result;\n }\n\n /**\n * Creates a clone of `arrayBuffer`.\n *\n * @private\n * @param {ArrayBuffer} arrayBuffer The array buffer to clone.\n * @returns {ArrayBuffer} Returns the cloned array buffer.\n */\n function cloneArrayBuffer(arrayBuffer) {\n var result = new arrayBuffer.constructor(arrayBuffer.byteLength);\n new Uint8Array(result).set(new Uint8Array(arrayBuffer));\n return result;\n }\n\n /**\n * Creates a clone of `dataView`.\n *\n * @private\n * @param {Object} dataView The data view to clone.\n * @param {boolean} [isDeep] Specify a deep clone.\n * @returns {Object} Returns the cloned data view.\n */\n function cloneDataView(dataView, isDeep) {\n var buffer = isDeep ? cloneArrayBuffer(dataView.buffer) : dataView.buffer;\n return new dataView.constructor(buffer, dataView.byteOffset, dataView.byteLength);\n }\n\n /**\n * Creates a clone of `regexp`.\n *\n * @private\n * @param {Object} regexp The regexp to clone.\n * @returns {Object} Returns the cloned regexp.\n */\n function cloneRegExp(regexp) {\n var result = new regexp.constructor(regexp.source, reFlags.exec(regexp));\n result.lastIndex = regexp.lastIndex;\n return result;\n }\n\n /**\n * Creates a clone of the `symbol` object.\n *\n * @private\n * @param {Object} symbol The symbol object to clone.\n * @returns {Object} Returns the cloned symbol object.\n */\n function cloneSymbol(symbol) {\n return symbolValueOf ? Object(symbolValueOf.call(symbol)) : {};\n }\n\n /**\n * Creates a clone of `typedArray`.\n *\n * @private\n * @param {Object} typedArray The typed array to clone.\n * @param {boolean} [isDeep] Specify a deep clone.\n * @returns {Object} Returns the cloned typed array.\n */\n function cloneTypedArray(typedArray, isDeep) {\n var buffer = isDeep ? cloneArrayBuffer(typedArray.buffer) : typedArray.buffer;\n return new typedArray.constructor(buffer, typedArray.byteOffset, typedArray.length);\n }\n\n /**\n * Compares values to sort them in ascending order.\n *\n * @private\n * @param {*} value The value to compare.\n * @param {*} other The other value to compare.\n * @returns {number} Returns the sort order indicator for `value`.\n */\n function compareAscending(value, other) {\n if (value !== other) {\n var valIsDefined = value !== undefined,\n valIsNull = value === null,\n valIsReflexive = value === value,\n valIsSymbol = isSymbol(value);\n\n var othIsDefined = other !== undefined,\n othIsNull = other === null,\n othIsReflexive = other === other,\n othIsSymbol = isSymbol(other);\n\n if ((!othIsNull && !othIsSymbol && !valIsSymbol && value > other) ||\n (valIsSymbol && othIsDefined && othIsReflexive && !othIsNull && !othIsSymbol) ||\n (valIsNull && othIsDefined && othIsReflexive) ||\n (!valIsDefined && othIsReflexive) ||\n !valIsReflexive) {\n return 1;\n }\n if ((!valIsNull && !valIsSymbol && !othIsSymbol && value < other) ||\n (othIsSymbol && valIsDefined && valIsReflexive && !valIsNull && !valIsSymbol) ||\n (othIsNull && valIsDefined && valIsReflexive) ||\n (!othIsDefined && valIsReflexive) ||\n !othIsReflexive) {\n return -1;\n }\n }\n return 0;\n }\n\n /**\n * Used by `_.orderBy` to compare multiple properties of a value to another\n * and stable sort them.\n *\n * If `orders` is unspecified, all values are sorted in ascending order. Otherwise,\n * specify an order of \"desc\" for descending or \"asc\" for ascending sort order\n * of corresponding values.\n *\n * @private\n * @param {Object} object The object to compare.\n * @param {Object} other The other object to compare.\n * @param {boolean[]|string[]} orders The order to sort by for each property.\n * @returns {number} Returns the sort order indicator for `object`.\n */\n function compareMultiple(object, other, orders) {\n var index = -1,\n objCriteria = object.criteria,\n othCriteria = other.criteria,\n length = objCriteria.length,\n ordersLength = orders.length;\n\n while (++index < length) {\n var result = compareAscending(objCriteria[index], othCriteria[index]);\n if (result) {\n if (index >= ordersLength) {\n return result;\n }\n var order = orders[index];\n return result * (order == 'desc' ? -1 : 1);\n }\n }\n // Fixes an `Array#sort` bug in the JS engine embedded in Adobe applications\n // that causes it, under certain circumstances, to provide the same value for\n // `object` and `other`. See https://github.com/jashkenas/underscore/pull/1247\n // for more details.\n //\n // This also ensures a stable sort in V8 and other engines.\n // See https://bugs.chromium.org/p/v8/issues/detail?id=90 for more details.\n return object.index - other.index;\n }\n\n /**\n * Creates an array that is the composition of partially applied arguments,\n * placeholders, and provided arguments into a single array of arguments.\n *\n * @private\n * @param {Array} args The provided arguments.\n * @param {Array} partials The arguments to prepend to those provided.\n * @param {Array} holders The `partials` placeholder indexes.\n * @params {boolean} [isCurried] Specify composing for a curried function.\n * @returns {Array} Returns the new array of composed arguments.\n */\n function composeArgs(args, partials, holders, isCurried) {\n var argsIndex = -1,\n argsLength = args.length,\n holdersLength = holders.length,\n leftIndex = -1,\n leftLength = partials.length,\n rangeLength = nativeMax(argsLength - holdersLength, 0),\n result = Array(leftLength + rangeLength),\n isUncurried = !isCurried;\n\n while (++leftIndex < leftLength) {\n result[leftIndex] = partials[leftIndex];\n }\n while (++argsIndex < holdersLength) {\n if (isUncurried || argsIndex < argsLength) {\n result[holders[argsIndex]] = args[argsIndex];\n }\n }\n while (rangeLength--) {\n result[leftIndex++] = args[argsIndex++];\n }\n return result;\n }\n\n /**\n * This function is like `composeArgs` except that the arguments composition\n * is tailored for `_.partialRight`.\n *\n * @private\n * @param {Array} args The provided arguments.\n * @param {Array} partials The arguments to append to those provided.\n * @param {Array} holders The `partials` placeholder indexes.\n * @params {boolean} [isCurried] Specify composing for a curried function.\n * @returns {Array} Returns the new array of composed arguments.\n */\n function composeArgsRight(args, partials, holders, isCurried) {\n var argsIndex = -1,\n argsLength = args.length,\n holdersIndex = -1,\n holdersLength = holders.length,\n rightIndex = -1,\n rightLength = partials.length,\n rangeLength = nativeMax(argsLength - holdersLength, 0),\n result = Array(rangeLength + rightLength),\n isUncurried = !isCurried;\n\n while (++argsIndex < rangeLength) {\n result[argsIndex] = args[argsIndex];\n }\n var offset = argsIndex;\n while (++rightIndex < rightLength) {\n result[offset + rightIndex] = partials[rightIndex];\n }\n while (++holdersIndex < holdersLength) {\n if (isUncurried || argsIndex < argsLength) {\n result[offset + holders[holdersIndex]] = args[argsIndex++];\n }\n }\n return result;\n }\n\n /**\n * Copies the values of `source` to `array`.\n *\n * @private\n * @param {Array} source The array to copy values from.\n * @param {Array} [array=[]] The array to copy values to.\n * @returns {Array} Returns `array`.\n */\n function copyArray(source, array) {\n var index = -1,\n length = source.length;\n\n array || (array = Array(length));\n while (++index < length) {\n array[index] = source[index];\n }\n return array;\n }\n\n /**\n * Copies properties of `source` to `object`.\n *\n * @private\n * @param {Object} source The object to copy properties from.\n * @param {Array} props The property identifiers to copy.\n * @param {Object} [object={}] The object to copy properties to.\n * @param {Function} [customizer] The function to customize copied values.\n * @returns {Object} Returns `object`.\n */\n function copyObject(source, props, object, customizer) {\n var isNew = !object;\n object || (object = {});\n\n var index = -1,\n length = props.length;\n\n while (++index < length) {\n var key = props[index];\n\n var newValue = customizer\n ? customizer(object[key], source[key], key, object, source)\n : undefined;\n\n if (newValue === undefined) {\n newValue = source[key];\n }\n if (isNew) {\n baseAssignValue(object, key, newValue);\n } else {\n assignValue(object, key, newValue);\n }\n }\n return object;\n }\n\n /**\n * Copies own symbols of `source` to `object`.\n *\n * @private\n * @param {Object} source The object to copy symbols from.\n * @param {Object} [object={}] The object to copy symbols to.\n * @returns {Object} Returns `object`.\n */\n function copySymbols(source, object) {\n return copyObject(source, getSymbols(source), object);\n }\n\n /**\n * Copies own and inherited symbols of `source` to `object`.\n *\n * @private\n * @param {Object} source The object to copy symbols from.\n * @param {Object} [object={}] The object to copy symbols to.\n * @returns {Object} Returns `object`.\n */\n function copySymbolsIn(source, object) {\n return copyObject(source, getSymbolsIn(source), object);\n }\n\n /**\n * Creates a function like `_.groupBy`.\n *\n * @private\n * @param {Function} setter The function to set accumulator values.\n * @param {Function} [initializer] The accumulator object initializer.\n * @returns {Function} Returns the new aggregator function.\n */\n function createAggregator(setter, initializer) {\n return function(collection, iteratee) {\n var func = isArray(collection) ? arrayAggregator : baseAggregator,\n accumulator = initializer ? initializer() : {};\n\n return func(collection, setter, getIteratee(iteratee, 2), accumulator);\n };\n }\n\n /**\n * Creates a function like `_.assign`.\n *\n * @private\n * @param {Function} assigner The function to assign values.\n * @returns {Function} Returns the new assigner function.\n */\n function createAssigner(assigner) {\n return baseRest(function(object, sources) {\n var index = -1,\n length = sources.length,\n customizer = length > 1 ? sources[length - 1] : undefined,\n guard = length > 2 ? sources[2] : undefined;\n\n customizer = (assigner.length > 3 && typeof customizer == 'function')\n ? (length--, customizer)\n : undefined;\n\n if (guard && isIterateeCall(sources[0], sources[1], guard)) {\n customizer = length < 3 ? undefined : customizer;\n length = 1;\n }\n object = Object(object);\n while (++index < length) {\n var source = sources[index];\n if (source) {\n assigner(object, source, index, customizer);\n }\n }\n return object;\n });\n }\n\n /**\n * Creates a `baseEach` or `baseEachRight` function.\n *\n * @private\n * @param {Function} eachFunc The function to iterate over a collection.\n * @param {boolean} [fromRight] Specify iterating from right to left.\n * @returns {Function} Returns the new base function.\n */\n function createBaseEach(eachFunc, fromRight) {\n return function(collection, iteratee) {\n if (collection == null) {\n return collection;\n }\n if (!isArrayLike(collection)) {\n return eachFunc(collection, iteratee);\n }\n var length = collection.length,\n index = fromRight ? length : -1,\n iterable = Object(collection);\n\n while ((fromRight ? index-- : ++index < length)) {\n if (iteratee(iterable[index], index, iterable) === false) {\n break;\n }\n }\n return collection;\n };\n }\n\n /**\n * Creates a base function for methods like `_.forIn` and `_.forOwn`.\n *\n * @private\n * @param {boolean} [fromRight] Specify iterating from right to left.\n * @returns {Function} Returns the new base function.\n */\n function createBaseFor(fromRight) {\n return function(object, iteratee, keysFunc) {\n var index = -1,\n iterable = Object(object),\n props = keysFunc(object),\n length = props.length;\n\n while (length--) {\n var key = props[fromRight ? length : ++index];\n if (iteratee(iterable[key], key, iterable) === false) {\n break;\n }\n }\n return object;\n };\n }\n\n /**\n * Creates a function that wraps `func` to invoke it with the optional `this`\n * binding of `thisArg`.\n *\n * @private\n * @param {Function} func The function to wrap.\n * @param {number} bitmask The bitmask flags. See `createWrap` for more details.\n * @param {*} [thisArg] The `this` binding of `func`.\n * @returns {Function} Returns the new wrapped function.\n */\n function createBind(func, bitmask, thisArg) {\n var isBind = bitmask & WRAP_BIND_FLAG,\n Ctor = createCtor(func);\n\n function wrapper() {\n var fn = (this && this !== root && this instanceof wrapper) ? Ctor : func;\n return fn.apply(isBind ? thisArg : this, arguments);\n }\n return wrapper;\n }\n\n /**\n * Creates a function like `_.lowerFirst`.\n *\n * @private\n * @param {string} methodName The name of the `String` case method to use.\n * @returns {Function} Returns the new case function.\n */\n function createCaseFirst(methodName) {\n return function(string) {\n string = toString(string);\n\n var strSymbols = hasUnicode(string)\n ? stringToArray(string)\n : undefined;\n\n var chr = strSymbols\n ? strSymbols[0]\n : string.charAt(0);\n\n var trailing = strSymbols\n ? castSlice(strSymbols, 1).join('')\n : string.slice(1);\n\n return chr[methodName]() + trailing;\n };\n }\n\n /**\n * Creates a function like `_.camelCase`.\n *\n * @private\n * @param {Function} callback The function to combine each word.\n * @returns {Function} Returns the new compounder function.\n */\n function createCompounder(callback) {\n return function(string) {\n return arrayReduce(words(deburr(string).replace(reApos, '')), callback, '');\n };\n }\n\n /**\n * Creates a function that produces an instance of `Ctor` regardless of\n * whether it was invoked as part of a `new` expression or by `call` or `apply`.\n *\n * @private\n * @param {Function} Ctor The constructor to wrap.\n * @returns {Function} Returns the new wrapped function.\n */\n function createCtor(Ctor) {\n return function() {\n // Use a `switch` statement to work with class constructors. See\n // http://ecma-international.org/ecma-262/7.0/#sec-ecmascript-function-objects-call-thisargument-argumentslist\n // for more details.\n var args = arguments;\n switch (args.length) {\n case 0: return new Ctor;\n case 1: return new Ctor(args[0]);\n case 2: return new Ctor(args[0], args[1]);\n case 3: return new Ctor(args[0], args[1], args[2]);\n case 4: return new Ctor(args[0], args[1], args[2], args[3]);\n case 5: return new Ctor(args[0], args[1], args[2], args[3], args[4]);\n case 6: return new Ctor(args[0], args[1], args[2], args[3], args[4], args[5]);\n case 7: return new Ctor(args[0], args[1], args[2], args[3], args[4], args[5], args[6]);\n }\n var thisBinding = baseCreate(Ctor.prototype),\n result = Ctor.apply(thisBinding, args);\n\n // Mimic the constructor's `return` behavior.\n // See https://es5.github.io/#x13.2.2 for more details.\n return isObject(result) ? result : thisBinding;\n };\n }\n\n /**\n * Creates a function that wraps `func` to enable currying.\n *\n * @private\n * @param {Function} func The function to wrap.\n * @param {number} bitmask The bitmask flags. See `createWrap` for more details.\n * @param {number} arity The arity of `func`.\n * @returns {Function} Returns the new wrapped function.\n */\n function createCurry(func, bitmask, arity) {\n var Ctor = createCtor(func);\n\n function wrapper() {\n var length = arguments.length,\n args = Array(length),\n index = length,\n placeholder = getHolder(wrapper);\n\n while (index--) {\n args[index] = arguments[index];\n }\n var holders = (length < 3 && args[0] !== placeholder && args[length - 1] !== placeholder)\n ? []\n : replaceHolders(args, placeholder);\n\n length -= holders.length;\n if (length < arity) {\n return createRecurry(\n func, bitmask, createHybrid, wrapper.placeholder, undefined,\n args, holders, undefined, undefined, arity - length);\n }\n var fn = (this && this !== root && this instanceof wrapper) ? Ctor : func;\n return apply(fn, this, args);\n }\n return wrapper;\n }\n\n /**\n * Creates a `_.find` or `_.findLast` function.\n *\n * @private\n * @param {Function} findIndexFunc The function to find the collection index.\n * @returns {Function} Returns the new find function.\n */\n function createFind(findIndexFunc) {\n return function(collection, predicate, fromIndex) {\n var iterable = Object(collection);\n if (!isArrayLike(collection)) {\n var iteratee = getIteratee(predicate, 3);\n collection = keys(collection);\n predicate = function(key) { return iteratee(iterable[key], key, iterable); };\n }\n var index = findIndexFunc(collection, predicate, fromIndex);\n return index > -1 ? iterable[iteratee ? collection[index] : index] : undefined;\n };\n }\n\n /**\n * Creates a `_.flow` or `_.flowRight` function.\n *\n * @private\n * @param {boolean} [fromRight] Specify iterating from right to left.\n * @returns {Function} Returns the new flow function.\n */\n function createFlow(fromRight) {\n return flatRest(function(funcs) {\n var length = funcs.length,\n index = length,\n prereq = LodashWrapper.prototype.thru;\n\n if (fromRight) {\n funcs.reverse();\n }\n while (index--) {\n var func = funcs[index];\n if (typeof func != 'function') {\n throw new TypeError(FUNC_ERROR_TEXT);\n }\n if (prereq && !wrapper && getFuncName(func) == 'wrapper') {\n var wrapper = new LodashWrapper([], true);\n }\n }\n index = wrapper ? index : length;\n while (++index < length) {\n func = funcs[index];\n\n var funcName = getFuncName(func),\n data = funcName == 'wrapper' ? getData(func) : undefined;\n\n if (data && isLaziable(data[0]) &&\n data[1] == (WRAP_ARY_FLAG | WRAP_CURRY_FLAG | WRAP_PARTIAL_FLAG | WRAP_REARG_FLAG) &&\n !data[4].length && data[9] == 1\n ) {\n wrapper = wrapper[getFuncName(data[0])].apply(wrapper, data[3]);\n } else {\n wrapper = (func.length == 1 && isLaziable(func))\n ? wrapper[funcName]()\n : wrapper.thru(func);\n }\n }\n return function() {\n var args = arguments,\n value = args[0];\n\n if (wrapper && args.length == 1 && isArray(value)) {\n return wrapper.plant(value).value();\n }\n var index = 0,\n result = length ? funcs[index].apply(this, args) : value;\n\n while (++index < length) {\n result = funcs[index].call(this, result);\n }\n return result;\n };\n });\n }\n\n /**\n * Creates a function that wraps `func` to invoke it with optional `this`\n * binding of `thisArg`, partial application, and currying.\n *\n * @private\n * @param {Function|string} func The function or method name to wrap.\n * @param {number} bitmask The bitmask flags. See `createWrap` for more details.\n * @param {*} [thisArg] The `this` binding of `func`.\n * @param {Array} [partials] The arguments to prepend to those provided to\n * the new function.\n * @param {Array} [holders] The `partials` placeholder indexes.\n * @param {Array} [partialsRight] The arguments to append to those provided\n * to the new function.\n * @param {Array} [holdersRight] The `partialsRight` placeholder indexes.\n * @param {Array} [argPos] The argument positions of the new function.\n * @param {number} [ary] The arity cap of `func`.\n * @param {number} [arity] The arity of `func`.\n * @returns {Function} Returns the new wrapped function.\n */\n function createHybrid(func, bitmask, thisArg, partials, holders, partialsRight, holdersRight, argPos, ary, arity) {\n var isAry = bitmask & WRAP_ARY_FLAG,\n isBind = bitmask & WRAP_BIND_FLAG,\n isBindKey = bitmask & WRAP_BIND_KEY_FLAG,\n isCurried = bitmask & (WRAP_CURRY_FLAG | WRAP_CURRY_RIGHT_FLAG),\n isFlip = bitmask & WRAP_FLIP_FLAG,\n Ctor = isBindKey ? undefined : createCtor(func);\n\n function wrapper() {\n var length = arguments.length,\n args = Array(length),\n index = length;\n\n while (index--) {\n args[index] = arguments[index];\n }\n if (isCurried) {\n var placeholder = getHolder(wrapper),\n holdersCount = countHolders(args, placeholder);\n }\n if (partials) {\n args = composeArgs(args, partials, holders, isCurried);\n }\n if (partialsRight) {\n args = composeArgsRight(args, partialsRight, holdersRight, isCurried);\n }\n length -= holdersCount;\n if (isCurried && length < arity) {\n var newHolders = replaceHolders(args, placeholder);\n return createRecurry(\n func, bitmask, createHybrid, wrapper.placeholder, thisArg,\n args, newHolders, argPos, ary, arity - length\n );\n }\n var thisBinding = isBind ? thisArg : this,\n fn = isBindKey ? thisBinding[func] : func;\n\n length = args.length;\n if (argPos) {\n args = reorder(args, argPos);\n } else if (isFlip && length > 1) {\n args.reverse();\n }\n if (isAry && ary < length) {\n args.length = ary;\n }\n if (this && this !== root && this instanceof wrapper) {\n fn = Ctor || createCtor(fn);\n }\n return fn.apply(thisBinding, args);\n }\n return wrapper;\n }\n\n /**\n * Creates a function like `_.invertBy`.\n *\n * @private\n * @param {Function} setter The function to set accumulator values.\n * @param {Function} toIteratee The function to resolve iteratees.\n * @returns {Function} Returns the new inverter function.\n */\n function createInverter(setter, toIteratee) {\n return function(object, iteratee) {\n return baseInverter(object, setter, toIteratee(iteratee), {});\n };\n }\n\n /**\n * Creates a function that performs a mathematical operation on two values.\n *\n * @private\n * @param {Function} operator The function to perform the operation.\n * @param {number} [defaultValue] The value used for `undefined` arguments.\n * @returns {Function} Returns the new mathematical operation function.\n */\n function createMathOperation(operator, defaultValue) {\n return function(value, other) {\n var result;\n if (value === undefined && other === undefined) {\n return defaultValue;\n }\n if (value !== undefined) {\n result = value;\n }\n if (other !== undefined) {\n if (result === undefined) {\n return other;\n }\n if (typeof value == 'string' || typeof other == 'string') {\n value = baseToString(value);\n other = baseToString(other);\n } else {\n value = baseToNumber(value);\n other = baseToNumber(other);\n }\n result = operator(value, other);\n }\n return result;\n };\n }\n\n /**\n * Creates a function like `_.over`.\n *\n * @private\n * @param {Function} arrayFunc The function to iterate over iteratees.\n * @returns {Function} Returns the new over function.\n */\n function createOver(arrayFunc) {\n return flatRest(function(iteratees) {\n iteratees = arrayMap(iteratees, baseUnary(getIteratee()));\n return baseRest(function(args) {\n var thisArg = this;\n return arrayFunc(iteratees, function(iteratee) {\n return apply(iteratee, thisArg, args);\n });\n });\n });\n }\n\n /**\n * Creates the padding for `string` based on `length`. The `chars` string\n * is truncated if the number of characters exceeds `length`.\n *\n * @private\n * @param {number} length The padding length.\n * @param {string} [chars=' '] The string used as padding.\n * @returns {string} Returns the padding for `string`.\n */\n function createPadding(length, chars) {\n chars = chars === undefined ? ' ' : baseToString(chars);\n\n var charsLength = chars.length;\n if (charsLength < 2) {\n return charsLength ? baseRepeat(chars, length) : chars;\n }\n var result = baseRepeat(chars, nativeCeil(length / stringSize(chars)));\n return hasUnicode(chars)\n ? castSlice(stringToArray(result), 0, length).join('')\n : result.slice(0, length);\n }\n\n /**\n * Creates a function that wraps `func` to invoke it with the `this` binding\n * of `thisArg` and `partials` prepended to the arguments it receives.\n *\n * @private\n * @param {Function} func The function to wrap.\n * @param {number} bitmask The bitmask flags. See `createWrap` for more details.\n * @param {*} thisArg The `this` binding of `func`.\n * @param {Array} partials The arguments to prepend to those provided to\n * the new function.\n * @returns {Function} Returns the new wrapped function.\n */\n function createPartial(func, bitmask, thisArg, partials) {\n var isBind = bitmask & WRAP_BIND_FLAG,\n Ctor = createCtor(func);\n\n function wrapper() {\n var argsIndex = -1,\n argsLength = arguments.length,\n leftIndex = -1,\n leftLength = partials.length,\n args = Array(leftLength + argsLength),\n fn = (this && this !== root && this instanceof wrapper) ? Ctor : func;\n\n while (++leftIndex < leftLength) {\n args[leftIndex] = partials[leftIndex];\n }\n while (argsLength--) {\n args[leftIndex++] = arguments[++argsIndex];\n }\n return apply(fn, isBind ? thisArg : this, args);\n }\n return wrapper;\n }\n\n /**\n * Creates a `_.range` or `_.rangeRight` function.\n *\n * @private\n * @param {boolean} [fromRight] Specify iterating from right to left.\n * @returns {Function} Returns the new range function.\n */\n function createRange(fromRight) {\n return function(start, end, step) {\n if (step && typeof step != 'number' && isIterateeCall(start, end, step)) {\n end = step = undefined;\n }\n // Ensure the sign of `-0` is preserved.\n start = toFinite(start);\n if (end === undefined) {\n end = start;\n start = 0;\n } else {\n end = toFinite(end);\n }\n step = step === undefined ? (start < end ? 1 : -1) : toFinite(step);\n return baseRange(start, end, step, fromRight);\n };\n }\n\n /**\n * Creates a function that performs a relational operation on two values.\n *\n * @private\n * @param {Function} operator The function to perform the operation.\n * @returns {Function} Returns the new relational operation function.\n */\n function createRelationalOperation(operator) {\n return function(value, other) {\n if (!(typeof value == 'string' && typeof other == 'string')) {\n value = toNumber(value);\n other = toNumber(other);\n }\n return operator(value, other);\n };\n }\n\n /**\n * Creates a function that wraps `func` to continue currying.\n *\n * @private\n * @param {Function} func The function to wrap.\n * @param {number} bitmask The bitmask flags. See `createWrap` for more details.\n * @param {Function} wrapFunc The function to create the `func` wrapper.\n * @param {*} placeholder The placeholder value.\n * @param {*} [thisArg] The `this` binding of `func`.\n * @param {Array} [partials] The arguments to prepend to those provided to\n * the new function.\n * @param {Array} [holders] The `partials` placeholder indexes.\n * @param {Array} [argPos] The argument positions of the new function.\n * @param {number} [ary] The arity cap of `func`.\n * @param {number} [arity] The arity of `func`.\n * @returns {Function} Returns the new wrapped function.\n */\n function createRecurry(func, bitmask, wrapFunc, placeholder, thisArg, partials, holders, argPos, ary, arity) {\n var isCurry = bitmask & WRAP_CURRY_FLAG,\n newHolders = isCurry ? holders : undefined,\n newHoldersRight = isCurry ? undefined : holders,\n newPartials = isCurry ? partials : undefined,\n newPartialsRight = isCurry ? undefined : partials;\n\n bitmask |= (isCurry ? WRAP_PARTIAL_FLAG : WRAP_PARTIAL_RIGHT_FLAG);\n bitmask &= ~(isCurry ? WRAP_PARTIAL_RIGHT_FLAG : WRAP_PARTIAL_FLAG);\n\n if (!(bitmask & WRAP_CURRY_BOUND_FLAG)) {\n bitmask &= ~(WRAP_BIND_FLAG | WRAP_BIND_KEY_FLAG);\n }\n var newData = [\n func, bitmask, thisArg, newPartials, newHolders, newPartialsRight,\n newHoldersRight, argPos, ary, arity\n ];\n\n var result = wrapFunc.apply(undefined, newData);\n if (isLaziable(func)) {\n setData(result, newData);\n }\n result.placeholder = placeholder;\n return setWrapToString(result, func, bitmask);\n }\n\n /**\n * Creates a function like `_.round`.\n *\n * @private\n * @param {string} methodName The name of the `Math` method to use when rounding.\n * @returns {Function} Returns the new round function.\n */\n function createRound(methodName) {\n var func = Math[methodName];\n return function(number, precision) {\n number = toNumber(number);\n precision = precision == null ? 0 : nativeMin(toInteger(precision), 292);\n if (precision && nativeIsFinite(number)) {\n // Shift with exponential notation to avoid floating-point issues.\n // See [MDN](https://mdn.io/round#Examples) for more details.\n var pair = (toString(number) + 'e').split('e'),\n value = func(pair[0] + 'e' + (+pair[1] + precision));\n\n pair = (toString(value) + 'e').split('e');\n return +(pair[0] + 'e' + (+pair[1] - precision));\n }\n return func(number);\n };\n }\n\n /**\n * Creates a set object of `values`.\n *\n * @private\n * @param {Array} values The values to add to the set.\n * @returns {Object} Returns the new set.\n */\n var createSet = !(Set && (1 / setToArray(new Set([,-0]))[1]) == INFINITY) ? noop : function(values) {\n return new Set(values);\n };\n\n /**\n * Creates a `_.toPairs` or `_.toPairsIn` function.\n *\n * @private\n * @param {Function} keysFunc The function to get the keys of a given object.\n * @returns {Function} Returns the new pairs function.\n */\n function createToPairs(keysFunc) {\n return function(object) {\n var tag = getTag(object);\n if (tag == mapTag) {\n return mapToArray(object);\n }\n if (tag == setTag) {\n return setToPairs(object);\n }\n return baseToPairs(object, keysFunc(object));\n };\n }\n\n /**\n * Creates a function that either curries or invokes `func` with optional\n * `this` binding and partially applied arguments.\n *\n * @private\n * @param {Function|string} func The function or method name to wrap.\n * @param {number} bitmask The bitmask flags.\n * 1 - `_.bind`\n * 2 - `_.bindKey`\n * 4 - `_.curry` or `_.curryRight` of a bound function\n * 8 - `_.curry`\n * 16 - `_.curryRight`\n * 32 - `_.partial`\n * 64 - `_.partialRight`\n * 128 - `_.rearg`\n * 256 - `_.ary`\n * 512 - `_.flip`\n * @param {*} [thisArg] The `this` binding of `func`.\n * @param {Array} [partials] The arguments to be partially applied.\n * @param {Array} [holders] The `partials` placeholder indexes.\n * @param {Array} [argPos] The argument positions of the new function.\n * @param {number} [ary] The arity cap of `func`.\n * @param {number} [arity] The arity of `func`.\n * @returns {Function} Returns the new wrapped function.\n */\n function createWrap(func, bitmask, thisArg, partials, holders, argPos, ary, arity) {\n var isBindKey = bitmask & WRAP_BIND_KEY_FLAG;\n if (!isBindKey && typeof func != 'function') {\n throw new TypeError(FUNC_ERROR_TEXT);\n }\n var length = partials ? partials.length : 0;\n if (!length) {\n bitmask &= ~(WRAP_PARTIAL_FLAG | WRAP_PARTIAL_RIGHT_FLAG);\n partials = holders = undefined;\n }\n ary = ary === undefined ? ary : nativeMax(toInteger(ary), 0);\n arity = arity === undefined ? arity : toInteger(arity);\n length -= holders ? holders.length : 0;\n\n if (bitmask & WRAP_PARTIAL_RIGHT_FLAG) {\n var partialsRight = partials,\n holdersRight = holders;\n\n partials = holders = undefined;\n }\n var data = isBindKey ? undefined : getData(func);\n\n var newData = [\n func, bitmask, thisArg, partials, holders, partialsRight, holdersRight,\n argPos, ary, arity\n ];\n\n if (data) {\n mergeData(newData, data);\n }\n func = newData[0];\n bitmask = newData[1];\n thisArg = newData[2];\n partials = newData[3];\n holders = newData[4];\n arity = newData[9] = newData[9] === undefined\n ? (isBindKey ? 0 : func.length)\n : nativeMax(newData[9] - length, 0);\n\n if (!arity && bitmask & (WRAP_CURRY_FLAG | WRAP_CURRY_RIGHT_FLAG)) {\n bitmask &= ~(WRAP_CURRY_FLAG | WRAP_CURRY_RIGHT_FLAG);\n }\n if (!bitmask || bitmask == WRAP_BIND_FLAG) {\n var result = createBind(func, bitmask, thisArg);\n } else if (bitmask == WRAP_CURRY_FLAG || bitmask == WRAP_CURRY_RIGHT_FLAG) {\n result = createCurry(func, bitmask, arity);\n } else if ((bitmask == WRAP_PARTIAL_FLAG || bitmask == (WRAP_BIND_FLAG | WRAP_PARTIAL_FLAG)) && !holders.length) {\n result = createPartial(func, bitmask, thisArg, partials);\n } else {\n result = createHybrid.apply(undefined, newData);\n }\n var setter = data ? baseSetData : setData;\n return setWrapToString(setter(result, newData), func, bitmask);\n }\n\n /**\n * Used by `_.defaults` to customize its `_.assignIn` use to assign properties\n * of source objects to the destination object for all destination properties\n * that resolve to `undefined`.\n *\n * @private\n * @param {*} objValue The destination value.\n * @param {*} srcValue The source value.\n * @param {string} key The key of the property to assign.\n * @param {Object} object The parent object of `objValue`.\n * @returns {*} Returns the value to assign.\n */\n function customDefaultsAssignIn(objValue, srcValue, key, object) {\n if (objValue === undefined ||\n (eq(objValue, objectProto[key]) && !hasOwnProperty.call(object, key))) {\n return srcValue;\n }\n return objValue;\n }\n\n /**\n * Used by `_.defaultsDeep` to customize its `_.merge` use to merge source\n * objects into destination objects that are passed thru.\n *\n * @private\n * @param {*} objValue The destination value.\n * @param {*} srcValue The source value.\n * @param {string} key The key of the property to merge.\n * @param {Object} object The parent object of `objValue`.\n * @param {Object} source The parent object of `srcValue`.\n * @param {Object} [stack] Tracks traversed source values and their merged\n * counterparts.\n * @returns {*} Returns the value to assign.\n */\n function customDefaultsMerge(objValue, srcValue, key, object, source, stack) {\n if (isObject(objValue) && isObject(srcValue)) {\n // Recursively merge objects and arrays (susceptible to call stack limits).\n stack.set(srcValue, objValue);\n baseMerge(objValue, srcValue, undefined, customDefaultsMerge, stack);\n stack['delete'](srcValue);\n }\n return objValue;\n }\n\n /**\n * Used by `_.omit` to customize its `_.cloneDeep` use to only clone plain\n * objects.\n *\n * @private\n * @param {*} value The value to inspect.\n * @param {string} key The key of the property to inspect.\n * @returns {*} Returns the uncloned value or `undefined` to defer cloning to `_.cloneDeep`.\n */\n function customOmitClone(value) {\n return isPlainObject(value) ? undefined : value;\n }\n\n /**\n * A specialized version of `baseIsEqualDeep` for arrays with support for\n * partial deep comparisons.\n *\n * @private\n * @param {Array} array The array to compare.\n * @param {Array} other The other array to compare.\n * @param {number} bitmask The bitmask flags. See `baseIsEqual` for more details.\n * @param {Function} customizer The function to customize comparisons.\n * @param {Function} equalFunc The function to determine equivalents of values.\n * @param {Object} stack Tracks traversed `array` and `other` objects.\n * @returns {boolean} Returns `true` if the arrays are equivalent, else `false`.\n */\n function equalArrays(array, other, bitmask, customizer, equalFunc, stack) {\n var isPartial = bitmask & COMPARE_PARTIAL_FLAG,\n arrLength = array.length,\n othLength = other.length;\n\n if (arrLength != othLength && !(isPartial && othLength > arrLength)) {\n return false;\n }\n // Assume cyclic values are equal.\n var stacked = stack.get(array);\n if (stacked && stack.get(other)) {\n return stacked == other;\n }\n var index = -1,\n result = true,\n seen = (bitmask & COMPARE_UNORDERED_FLAG) ? new SetCache : undefined;\n\n stack.set(array, other);\n stack.set(other, array);\n\n // Ignore non-index properties.\n while (++index < arrLength) {\n var arrValue = array[index],\n othValue = other[index];\n\n if (customizer) {\n var compared = isPartial\n ? customizer(othValue, arrValue, index, other, array, stack)\n : customizer(arrValue, othValue, index, array, other, stack);\n }\n if (compared !== undefined) {\n if (compared) {\n continue;\n }\n result = false;\n break;\n }\n // Recursively compare arrays (susceptible to call stack limits).\n if (seen) {\n if (!arraySome(other, function(othValue, othIndex) {\n if (!cacheHas(seen, othIndex) &&\n (arrValue === othValue || equalFunc(arrValue, othValue, bitmask, customizer, stack))) {\n return seen.push(othIndex);\n }\n })) {\n result = false;\n break;\n }\n } else if (!(\n arrValue === othValue ||\n equalFunc(arrValue, othValue, bitmask, customizer, stack)\n )) {\n result = false;\n break;\n }\n }\n stack['delete'](array);\n stack['delete'](other);\n return result;\n }\n\n /**\n * A specialized version of `baseIsEqualDeep` for comparing objects of\n * the same `toStringTag`.\n *\n * **Note:** This function only supports comparing values with tags of\n * `Boolean`, `Date`, `Error`, `Number`, `RegExp`, or `String`.\n *\n * @private\n * @param {Object} object The object to compare.\n * @param {Object} other The other object to compare.\n * @param {string} tag The `toStringTag` of the objects to compare.\n * @param {number} bitmask The bitmask flags. See `baseIsEqual` for more details.\n * @param {Function} customizer The function to customize comparisons.\n * @param {Function} equalFunc The function to determine equivalents of values.\n * @param {Object} stack Tracks traversed `object` and `other` objects.\n * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.\n */\n function equalByTag(object, other, tag, bitmask, customizer, equalFunc, stack) {\n switch (tag) {\n case dataViewTag:\n if ((object.byteLength != other.byteLength) ||\n (object.byteOffset != other.byteOffset)) {\n return false;\n }\n object = object.buffer;\n other = other.buffer;\n\n case arrayBufferTag:\n if ((object.byteLength != other.byteLength) ||\n !equalFunc(new Uint8Array(object), new Uint8Array(other))) {\n return false;\n }\n return true;\n\n case boolTag:\n case dateTag:\n case numberTag:\n // Coerce booleans to `1` or `0` and dates to milliseconds.\n // Invalid dates are coerced to `NaN`.\n return eq(+object, +other);\n\n case errorTag:\n return object.name == other.name && object.message == other.message;\n\n case regexpTag:\n case stringTag:\n // Coerce regexes to strings and treat strings, primitives and objects,\n // as equal. See http://www.ecma-international.org/ecma-262/7.0/#sec-regexp.prototype.tostring\n // for more details.\n return object == (other + '');\n\n case mapTag:\n var convert = mapToArray;\n\n case setTag:\n var isPartial = bitmask & COMPARE_PARTIAL_FLAG;\n convert || (convert = setToArray);\n\n if (object.size != other.size && !isPartial) {\n return false;\n }\n // Assume cyclic values are equal.\n var stacked = stack.get(object);\n if (stacked) {\n return stacked == other;\n }\n bitmask |= COMPARE_UNORDERED_FLAG;\n\n // Recursively compare objects (susceptible to call stack limits).\n stack.set(object, other);\n var result = equalArrays(convert(object), convert(other), bitmask, customizer, equalFunc, stack);\n stack['delete'](object);\n return result;\n\n case symbolTag:\n if (symbolValueOf) {\n return symbolValueOf.call(object) == symbolValueOf.call(other);\n }\n }\n return false;\n }\n\n /**\n * A specialized version of `baseIsEqualDeep` for objects with support for\n * partial deep comparisons.\n *\n * @private\n * @param {Object} object The object to compare.\n * @param {Object} other The other object to compare.\n * @param {number} bitmask The bitmask flags. See `baseIsEqual` for more details.\n * @param {Function} customizer The function to customize comparisons.\n * @param {Function} equalFunc The function to determine equivalents of values.\n * @param {Object} stack Tracks traversed `object` and `other` objects.\n * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.\n */\n function equalObjects(object, other, bitmask, customizer, equalFunc, stack) {\n var isPartial = bitmask & COMPARE_PARTIAL_FLAG,\n objProps = getAllKeys(object),\n objLength = objProps.length,\n othProps = getAllKeys(other),\n othLength = othProps.length;\n\n if (objLength != othLength && !isPartial) {\n return false;\n }\n var index = objLength;\n while (index--) {\n var key = objProps[index];\n if (!(isPartial ? key in other : hasOwnProperty.call(other, key))) {\n return false;\n }\n }\n // Assume cyclic values are equal.\n var stacked = stack.get(object);\n if (stacked && stack.get(other)) {\n return stacked == other;\n }\n var result = true;\n stack.set(object, other);\n stack.set(other, object);\n\n var skipCtor = isPartial;\n while (++index < objLength) {\n key = objProps[index];\n var objValue = object[key],\n othValue = other[key];\n\n if (customizer) {\n var compared = isPartial\n ? customizer(othValue, objValue, key, other, object, stack)\n : customizer(objValue, othValue, key, object, other, stack);\n }\n // Recursively compare objects (susceptible to call stack limits).\n if (!(compared === undefined\n ? (objValue === othValue || equalFunc(objValue, othValue, bitmask, customizer, stack))\n : compared\n )) {\n result = false;\n break;\n }\n skipCtor || (skipCtor = key == 'constructor');\n }\n if (result && !skipCtor) {\n var objCtor = object.constructor,\n othCtor = other.constructor;\n\n // Non `Object` object instances with different constructors are not equal.\n if (objCtor != othCtor &&\n ('constructor' in object && 'constructor' in other) &&\n !(typeof objCtor == 'function' && objCtor instanceof objCtor &&\n typeof othCtor == 'function' && othCtor instanceof othCtor)) {\n result = false;\n }\n }\n stack['delete'](object);\n stack['delete'](other);\n return result;\n }\n\n /**\n * A specialized version of `baseRest` which flattens the rest array.\n *\n * @private\n * @param {Function} func The function to apply a rest parameter to.\n * @returns {Function} Returns the new function.\n */\n function flatRest(func) {\n return setToString(overRest(func, undefined, flatten), func + '');\n }\n\n /**\n * Creates an array of own enumerable property names and symbols of `object`.\n *\n * @private\n * @param {Object} object The object to query.\n * @returns {Array} Returns the array of property names and symbols.\n */\n function getAllKeys(object) {\n return baseGetAllKeys(object, keys, getSymbols);\n }\n\n /**\n * Creates an array of own and inherited enumerable property names and\n * symbols of `object`.\n *\n * @private\n * @param {Object} object The object to query.\n * @returns {Array} Returns the array of property names and symbols.\n */\n function getAllKeysIn(object) {\n return baseGetAllKeys(object, keysIn, getSymbolsIn);\n }\n\n /**\n * Gets metadata for `func`.\n *\n * @private\n * @param {Function} func The function to query.\n * @returns {*} Returns the metadata for `func`.\n */\n var getData = !metaMap ? noop : function(func) {\n return metaMap.get(func);\n };\n\n /**\n * Gets the name of `func`.\n *\n * @private\n * @param {Function} func The function to query.\n * @returns {string} Returns the function name.\n */\n function getFuncName(func) {\n var result = (func.name + ''),\n array = realNames[result],\n length = hasOwnProperty.call(realNames, result) ? array.length : 0;\n\n while (length--) {\n var data = array[length],\n otherFunc = data.func;\n if (otherFunc == null || otherFunc == func) {\n return data.name;\n }\n }\n return result;\n }\n\n /**\n * Gets the argument placeholder value for `func`.\n *\n * @private\n * @param {Function} func The function to inspect.\n * @returns {*} Returns the placeholder value.\n */\n function getHolder(func) {\n var object = hasOwnProperty.call(lodash, 'placeholder') ? lodash : func;\n return object.placeholder;\n }\n\n /**\n * Gets the appropriate \"iteratee\" function. If `_.iteratee` is customized,\n * this function returns the custom method, otherwise it returns `baseIteratee`.\n * If arguments are provided, the chosen function is invoked with them and\n * its result is returned.\n *\n * @private\n * @param {*} [value] The value to convert to an iteratee.\n * @param {number} [arity] The arity of the created iteratee.\n * @returns {Function} Returns the chosen function or its result.\n */\n function getIteratee() {\n var result = lodash.iteratee || iteratee;\n result = result === iteratee ? baseIteratee : result;\n return arguments.length ? result(arguments[0], arguments[1]) : result;\n }\n\n /**\n * Gets the data for `map`.\n *\n * @private\n * @param {Object} map The map to query.\n * @param {string} key The reference key.\n * @returns {*} Returns the map data.\n */\n function getMapData(map, key) {\n var data = map.__data__;\n return isKeyable(key)\n ? data[typeof key == 'string' ? 'string' : 'hash']\n : data.map;\n }\n\n /**\n * Gets the property names, values, and compare flags of `object`.\n *\n * @private\n * @param {Object} object The object to query.\n * @returns {Array} Returns the match data of `object`.\n */\n function getMatchData(object) {\n var result = keys(object),\n length = result.length;\n\n while (length--) {\n var key = result[length],\n value = object[key];\n\n result[length] = [key, value, isStrictComparable(value)];\n }\n return result;\n }\n\n /**\n * Gets the native function at `key` of `object`.\n *\n * @private\n * @param {Object} object The object to query.\n * @param {string} key The key of the method to get.\n * @returns {*} Returns the function if it's native, else `undefined`.\n */\n function getNative(object, key) {\n var value = getValue(object, key);\n return baseIsNative(value) ? value : undefined;\n }\n\n /**\n * A specialized version of `baseGetTag` which ignores `Symbol.toStringTag` values.\n *\n * @private\n * @param {*} value The value to query.\n * @returns {string} Returns the raw `toStringTag`.\n */\n function getRawTag(value) {\n var isOwn = hasOwnProperty.call(value, symToStringTag),\n tag = value[symToStringTag];\n\n try {\n value[symToStringTag] = undefined;\n var unmasked = true;\n } catch (e) {}\n\n var result = nativeObjectToString.call(value);\n if (unmasked) {\n if (isOwn) {\n value[symToStringTag] = tag;\n } else {\n delete value[symToStringTag];\n }\n }\n return result;\n }\n\n /**\n * Creates an array of the own enumerable symbols of `object`.\n *\n * @private\n * @param {Object} object The object to query.\n * @returns {Array} Returns the array of symbols.\n */\n var getSymbols = !nativeGetSymbols ? stubArray : function(object) {\n if (object == null) {\n return [];\n }\n object = Object(object);\n return arrayFilter(nativeGetSymbols(object), function(symbol) {\n return propertyIsEnumerable.call(object, symbol);\n });\n };\n\n /**\n * Creates an array of the own and inherited enumerable symbols of `object`.\n *\n * @private\n * @param {Object} object The object to query.\n * @returns {Array} Returns the array of symbols.\n */\n var getSymbolsIn = !nativeGetSymbols ? stubArray : function(object) {\n var result = [];\n while (object) {\n arrayPush(result, getSymbols(object));\n object = getPrototype(object);\n }\n return result;\n };\n\n /**\n * Gets the `toStringTag` of `value`.\n *\n * @private\n * @param {*} value The value to query.\n * @returns {string} Returns the `toStringTag`.\n */\n var getTag = baseGetTag;\n\n // Fallback for data views, maps, sets, and weak maps in IE 11 and promises in Node.js < 6.\n if ((DataView && getTag(new DataView(new ArrayBuffer(1))) != dataViewTag) ||\n (Map && getTag(new Map) != mapTag) ||\n (Promise && getTag(Promise.resolve()) != promiseTag) ||\n (Set && getTag(new Set) != setTag) ||\n (WeakMap && getTag(new WeakMap) != weakMapTag)) {\n getTag = function(value) {\n var result = baseGetTag(value),\n Ctor = result == objectTag ? value.constructor : undefined,\n ctorString = Ctor ? toSource(Ctor) : '';\n\n if (ctorString) {\n switch (ctorString) {\n case dataViewCtorString: return dataViewTag;\n case mapCtorString: return mapTag;\n case promiseCtorString: return promiseTag;\n case setCtorString: return setTag;\n case weakMapCtorString: return weakMapTag;\n }\n }\n return result;\n };\n }\n\n /**\n * Gets the view, applying any `transforms` to the `start` and `end` positions.\n *\n * @private\n * @param {number} start The start of the view.\n * @param {number} end The end of the view.\n * @param {Array} transforms The transformations to apply to the view.\n * @returns {Object} Returns an object containing the `start` and `end`\n * positions of the view.\n */\n function getView(start, end, transforms) {\n var index = -1,\n length = transforms.length;\n\n while (++index < length) {\n var data = transforms[index],\n size = data.size;\n\n switch (data.type) {\n case 'drop': start += size; break;\n case 'dropRight': end -= size; break;\n case 'take': end = nativeMin(end, start + size); break;\n case 'takeRight': start = nativeMax(start, end - size); break;\n }\n }\n return { 'start': start, 'end': end };\n }\n\n /**\n * Extracts wrapper details from the `source` body comment.\n *\n * @private\n * @param {string} source The source to inspect.\n * @returns {Array} Returns the wrapper details.\n */\n function getWrapDetails(source) {\n var match = source.match(reWrapDetails);\n return match ? match[1].split(reSplitDetails) : [];\n }\n\n /**\n * Checks if `path` exists on `object`.\n *\n * @private\n * @param {Object} object The object to query.\n * @param {Array|string} path The path to check.\n * @param {Function} hasFunc The function to check properties.\n * @returns {boolean} Returns `true` if `path` exists, else `false`.\n */\n function hasPath(object, path, hasFunc) {\n path = castPath(path, object);\n\n var index = -1,\n length = path.length,\n result = false;\n\n while (++index < length) {\n var key = toKey(path[index]);\n if (!(result = object != null && hasFunc(object, key))) {\n break;\n }\n object = object[key];\n }\n if (result || ++index != length) {\n return result;\n }\n length = object == null ? 0 : object.length;\n return !!length && isLength(length) && isIndex(key, length) &&\n (isArray(object) || isArguments(object));\n }\n\n /**\n * Initializes an array clone.\n *\n * @private\n * @param {Array} array The array to clone.\n * @returns {Array} Returns the initialized clone.\n */\n function initCloneArray(array) {\n var length = array.length,\n result = new array.constructor(length);\n\n // Add properties assigned by `RegExp#exec`.\n if (length && typeof array[0] == 'string' && hasOwnProperty.call(array, 'index')) {\n result.index = array.index;\n result.input = array.input;\n }\n return result;\n }\n\n /**\n * Initializes an object clone.\n *\n * @private\n * @param {Object} object The object to clone.\n * @returns {Object} Returns the initialized clone.\n */\n function initCloneObject(object) {\n return (typeof object.constructor == 'function' && !isPrototype(object))\n ? baseCreate(getPrototype(object))\n : {};\n }\n\n /**\n * Initializes an object clone based on its `toStringTag`.\n *\n * **Note:** This function only supports cloning values with tags of\n * `Boolean`, `Date`, `Error`, `Map`, `Number`, `RegExp`, `Set`, or `String`.\n *\n * @private\n * @param {Object} object The object to clone.\n * @param {string} tag The `toStringTag` of the object to clone.\n * @param {boolean} [isDeep] Specify a deep clone.\n * @returns {Object} Returns the initialized clone.\n */\n function initCloneByTag(object, tag, isDeep) {\n var Ctor = object.constructor;\n switch (tag) {\n case arrayBufferTag:\n return cloneArrayBuffer(object);\n\n case boolTag:\n case dateTag:\n return new Ctor(+object);\n\n case dataViewTag:\n return cloneDataView(object, isDeep);\n\n case float32Tag: case float64Tag:\n case int8Tag: case int16Tag: case int32Tag:\n case uint8Tag: case uint8ClampedTag: case uint16Tag: case uint32Tag:\n return cloneTypedArray(object, isDeep);\n\n case mapTag:\n return new Ctor;\n\n case numberTag:\n case stringTag:\n return new Ctor(object);\n\n case regexpTag:\n return cloneRegExp(object);\n\n case setTag:\n return new Ctor;\n\n case symbolTag:\n return cloneSymbol(object);\n }\n }\n\n /**\n * Inserts wrapper `details` in a comment at the top of the `source` body.\n *\n * @private\n * @param {string} source The source to modify.\n * @returns {Array} details The details to insert.\n * @returns {string} Returns the modified source.\n */\n function insertWrapDetails(source, details) {\n var length = details.length;\n if (!length) {\n return source;\n }\n var lastIndex = length - 1;\n details[lastIndex] = (length > 1 ? '& ' : '') + details[lastIndex];\n details = details.join(length > 2 ? ', ' : ' ');\n return source.replace(reWrapComment, '{\\n/* [wrapped with ' + details + '] */\\n');\n }\n\n /**\n * Checks if `value` is a flattenable `arguments` object or array.\n *\n * @private\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is flattenable, else `false`.\n */\n function isFlattenable(value) {\n return isArray(value) || isArguments(value) ||\n !!(spreadableSymbol && value && value[spreadableSymbol]);\n }\n\n /**\n * Checks if `value` is a valid array-like index.\n *\n * @private\n * @param {*} value The value to check.\n * @param {number} [length=MAX_SAFE_INTEGER] The upper bounds of a valid index.\n * @returns {boolean} Returns `true` if `value` is a valid index, else `false`.\n */\n function isIndex(value, length) {\n var type = typeof value;\n length = length == null ? MAX_SAFE_INTEGER : length;\n\n return !!length &&\n (type == 'number' ||\n (type != 'symbol' && reIsUint.test(value))) &&\n (value > -1 && value % 1 == 0 && value < length);\n }\n\n /**\n * Checks if the given arguments are from an iteratee call.\n *\n * @private\n * @param {*} value The potential iteratee value argument.\n * @param {*} index The potential iteratee index or key argument.\n * @param {*} object The potential iteratee object argument.\n * @returns {boolean} Returns `true` if the arguments are from an iteratee call,\n * else `false`.\n */\n function isIterateeCall(value, index, object) {\n if (!isObject(object)) {\n return false;\n }\n var type = typeof index;\n if (type == 'number'\n ? (isArrayLike(object) && isIndex(index, object.length))\n : (type == 'string' && index in object)\n ) {\n return eq(object[index], value);\n }\n return false;\n }\n\n /**\n * Checks if `value` is a property name and not a property path.\n *\n * @private\n * @param {*} value The value to check.\n * @param {Object} [object] The object to query keys on.\n * @returns {boolean} Returns `true` if `value` is a property name, else `false`.\n */\n function isKey(value, object) {\n if (isArray(value)) {\n return false;\n }\n var type = typeof value;\n if (type == 'number' || type == 'symbol' || type == 'boolean' ||\n value == null || isSymbol(value)) {\n return true;\n }\n return reIsPlainProp.test(value) || !reIsDeepProp.test(value) ||\n (object != null && value in Object(object));\n }\n\n /**\n * Checks if `value` is suitable for use as unique object key.\n *\n * @private\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is suitable, else `false`.\n */\n function isKeyable(value) {\n var type = typeof value;\n return (type == 'string' || type == 'number' || type == 'symbol' || type == 'boolean')\n ? (value !== '__proto__')\n : (value === null);\n }\n\n /**\n * Checks if `func` has a lazy counterpart.\n *\n * @private\n * @param {Function} func The function to check.\n * @returns {boolean} Returns `true` if `func` has a lazy counterpart,\n * else `false`.\n */\n function isLaziable(func) {\n var funcName = getFuncName(func),\n other = lodash[funcName];\n\n if (typeof other != 'function' || !(funcName in LazyWrapper.prototype)) {\n return false;\n }\n if (func === other) {\n return true;\n }\n var data = getData(other);\n return !!data && func === data[0];\n }\n\n /**\n * Checks if `func` has its source masked.\n *\n * @private\n * @param {Function} func The function to check.\n * @returns {boolean} Returns `true` if `func` is masked, else `false`.\n */\n function isMasked(func) {\n return !!maskSrcKey && (maskSrcKey in func);\n }\n\n /**\n * Checks if `func` is capable of being masked.\n *\n * @private\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `func` is maskable, else `false`.\n */\n var isMaskable = coreJsData ? isFunction : stubFalse;\n\n /**\n * Checks if `value` is likely a prototype object.\n *\n * @private\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a prototype, else `false`.\n */\n function isPrototype(value) {\n var Ctor = value && value.constructor,\n proto = (typeof Ctor == 'function' && Ctor.prototype) || objectProto;\n\n return value === proto;\n }\n\n /**\n * Checks if `value` is suitable for strict equality comparisons, i.e. `===`.\n *\n * @private\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` if suitable for strict\n * equality comparisons, else `false`.\n */\n function isStrictComparable(value) {\n return value === value && !isObject(value);\n }\n\n /**\n * A specialized version of `matchesProperty` for source values suitable\n * for strict equality comparisons, i.e. `===`.\n *\n * @private\n * @param {string} key The key of the property to get.\n * @param {*} srcValue The value to match.\n * @returns {Function} Returns the new spec function.\n */\n function matchesStrictComparable(key, srcValue) {\n return function(object) {\n if (object == null) {\n return false;\n }\n return object[key] === srcValue &&\n (srcValue !== undefined || (key in Object(object)));\n };\n }\n\n /**\n * A specialized version of `_.memoize` which clears the memoized function's\n * cache when it exceeds `MAX_MEMOIZE_SIZE`.\n *\n * @private\n * @param {Function} func The function to have its output memoized.\n * @returns {Function} Returns the new memoized function.\n */\n function memoizeCapped(func) {\n var result = memoize(func, function(key) {\n if (cache.size === MAX_MEMOIZE_SIZE) {\n cache.clear();\n }\n return key;\n });\n\n var cache = result.cache;\n return result;\n }\n\n /**\n * Merges the function metadata of `source` into `data`.\n *\n * Merging metadata reduces the number of wrappers used to invoke a function.\n * This is possible because methods like `_.bind`, `_.curry`, and `_.partial`\n * may be applied regardless of execution order. Methods like `_.ary` and\n * `_.rearg` modify function arguments, making the order in which they are\n * executed important, preventing the merging of metadata. However, we make\n * an exception for a safe combined case where curried functions have `_.ary`\n * and or `_.rearg` applied.\n *\n * @private\n * @param {Array} data The destination metadata.\n * @param {Array} source The source metadata.\n * @returns {Array} Returns `data`.\n */\n function mergeData(data, source) {\n var bitmask = data[1],\n srcBitmask = source[1],\n newBitmask = bitmask | srcBitmask,\n isCommon = newBitmask < (WRAP_BIND_FLAG | WRAP_BIND_KEY_FLAG | WRAP_ARY_FLAG);\n\n var isCombo =\n ((srcBitmask == WRAP_ARY_FLAG) && (bitmask == WRAP_CURRY_FLAG)) ||\n ((srcBitmask == WRAP_ARY_FLAG) && (bitmask == WRAP_REARG_FLAG) && (data[7].length <= source[8])) ||\n ((srcBitmask == (WRAP_ARY_FLAG | WRAP_REARG_FLAG)) && (source[7].length <= source[8]) && (bitmask == WRAP_CURRY_FLAG));\n\n // Exit early if metadata can't be merged.\n if (!(isCommon || isCombo)) {\n return data;\n }\n // Use source `thisArg` if available.\n if (srcBitmask & WRAP_BIND_FLAG) {\n data[2] = source[2];\n // Set when currying a bound function.\n newBitmask |= bitmask & WRAP_BIND_FLAG ? 0 : WRAP_CURRY_BOUND_FLAG;\n }\n // Compose partial arguments.\n var value = source[3];\n if (value) {\n var partials = data[3];\n data[3] = partials ? composeArgs(partials, value, source[4]) : value;\n data[4] = partials ? replaceHolders(data[3], PLACEHOLDER) : source[4];\n }\n // Compose partial right arguments.\n value = source[5];\n if (value) {\n partials = data[5];\n data[5] = partials ? composeArgsRight(partials, value, source[6]) : value;\n data[6] = partials ? replaceHolders(data[5], PLACEHOLDER) : source[6];\n }\n // Use source `argPos` if available.\n value = source[7];\n if (value) {\n data[7] = value;\n }\n // Use source `ary` if it's smaller.\n if (srcBitmask & WRAP_ARY_FLAG) {\n data[8] = data[8] == null ? source[8] : nativeMin(data[8], source[8]);\n }\n // Use source `arity` if one is not provided.\n if (data[9] == null) {\n data[9] = source[9];\n }\n // Use source `func` and merge bitmasks.\n data[0] = source[0];\n data[1] = newBitmask;\n\n return data;\n }\n\n /**\n * This function is like\n * [`Object.keys`](http://ecma-international.org/ecma-262/7.0/#sec-object.keys)\n * except that it includes inherited enumerable properties.\n *\n * @private\n * @param {Object} object The object to query.\n * @returns {Array} Returns the array of property names.\n */\n function nativeKeysIn(object) {\n var result = [];\n if (object != null) {\n for (var key in Object(object)) {\n result.push(key);\n }\n }\n return result;\n }\n\n /**\n * Converts `value` to a string using `Object.prototype.toString`.\n *\n * @private\n * @param {*} value The value to convert.\n * @returns {string} Returns the converted string.\n */\n function objectToString(value) {\n return nativeObjectToString.call(value);\n }\n\n /**\n * A specialized version of `baseRest` which transforms the rest array.\n *\n * @private\n * @param {Function} func The function to apply a rest parameter to.\n * @param {number} [start=func.length-1] The start position of the rest parameter.\n * @param {Function} transform The rest array transform.\n * @returns {Function} Returns the new function.\n */\n function overRest(func, start, transform) {\n start = nativeMax(start === undefined ? (func.length - 1) : start, 0);\n return function() {\n var args = arguments,\n index = -1,\n length = nativeMax(args.length - start, 0),\n array = Array(length);\n\n while (++index < length) {\n array[index] = args[start + index];\n }\n index = -1;\n var otherArgs = Array(start + 1);\n while (++index < start) {\n otherArgs[index] = args[index];\n }\n otherArgs[start] = transform(array);\n return apply(func, this, otherArgs);\n };\n }\n\n /**\n * Gets the parent value at `path` of `object`.\n *\n * @private\n * @param {Object} object The object to query.\n * @param {Array} path The path to get the parent value of.\n * @returns {*} Returns the parent value.\n */\n function parent(object, path) {\n return path.length < 2 ? object : baseGet(object, baseSlice(path, 0, -1));\n }\n\n /**\n * Reorder `array` according to the specified indexes where the element at\n * the first index is assigned as the first element, the element at\n * the second index is assigned as the second element, and so on.\n *\n * @private\n * @param {Array} array The array to reorder.\n * @param {Array} indexes The arranged array indexes.\n * @returns {Array} Returns `array`.\n */\n function reorder(array, indexes) {\n var arrLength = array.length,\n length = nativeMin(indexes.length, arrLength),\n oldArray = copyArray(array);\n\n while (length--) {\n var index = indexes[length];\n array[length] = isIndex(index, arrLength) ? oldArray[index] : undefined;\n }\n return array;\n }\n\n /**\n * Gets the value at `key`, unless `key` is \"__proto__\" or \"constructor\".\n *\n * @private\n * @param {Object} object The object to query.\n * @param {string} key The key of the property to get.\n * @returns {*} Returns the property value.\n */\n function safeGet(object, key) {\n if (key === 'constructor' && typeof object[key] === 'function') {\n return;\n }\n\n if (key == '__proto__') {\n return;\n }\n\n return object[key];\n }\n\n /**\n * Sets metadata for `func`.\n *\n * **Note:** If this function becomes hot, i.e. is invoked a lot in a short\n * period of time, it will trip its breaker and transition to an identity\n * function to avoid garbage collection pauses in V8. See\n * [V8 issue 2070](https://bugs.chromium.org/p/v8/issues/detail?id=2070)\n * for more details.\n *\n * @private\n * @param {Function} func The function to associate metadata with.\n * @param {*} data The metadata.\n * @returns {Function} Returns `func`.\n */\n var setData = shortOut(baseSetData);\n\n /**\n * A simple wrapper around the global [`setTimeout`](https://mdn.io/setTimeout).\n *\n * @private\n * @param {Function} func The function to delay.\n * @param {number} wait The number of milliseconds to delay invocation.\n * @returns {number|Object} Returns the timer id or timeout object.\n */\n var setTimeout = ctxSetTimeout || function(func, wait) {\n return root.setTimeout(func, wait);\n };\n\n /**\n * Sets the `toString` method of `func` to return `string`.\n *\n * @private\n * @param {Function} func The function to modify.\n * @param {Function} string The `toString` result.\n * @returns {Function} Returns `func`.\n */\n var setToString = shortOut(baseSetToString);\n\n /**\n * Sets the `toString` method of `wrapper` to mimic the source of `reference`\n * with wrapper details in a comment at the top of the source body.\n *\n * @private\n * @param {Function} wrapper The function to modify.\n * @param {Function} reference The reference function.\n * @param {number} bitmask The bitmask flags. See `createWrap` for more details.\n * @returns {Function} Returns `wrapper`.\n */\n function setWrapToString(wrapper, reference, bitmask) {\n var source = (reference + '');\n return setToString(wrapper, insertWrapDetails(source, updateWrapDetails(getWrapDetails(source), bitmask)));\n }\n\n /**\n * Creates a function that'll short out and invoke `identity` instead\n * of `func` when it's called `HOT_COUNT` or more times in `HOT_SPAN`\n * milliseconds.\n *\n * @private\n * @param {Function} func The function to restrict.\n * @returns {Function} Returns the new shortable function.\n */\n function shortOut(func) {\n var count = 0,\n lastCalled = 0;\n\n return function() {\n var stamp = nativeNow(),\n remaining = HOT_SPAN - (stamp - lastCalled);\n\n lastCalled = stamp;\n if (remaining > 0) {\n if (++count >= HOT_COUNT) {\n return arguments[0];\n }\n } else {\n count = 0;\n }\n return func.apply(undefined, arguments);\n };\n }\n\n /**\n * A specialized version of `_.shuffle` which mutates and sets the size of `array`.\n *\n * @private\n * @param {Array} array The array to shuffle.\n * @param {number} [size=array.length] The size of `array`.\n * @returns {Array} Returns `array`.\n */\n function shuffleSelf(array, size) {\n var index = -1,\n length = array.length,\n lastIndex = length - 1;\n\n size = size === undefined ? length : size;\n while (++index < size) {\n var rand = baseRandom(index, lastIndex),\n value = array[rand];\n\n array[rand] = array[index];\n array[index] = value;\n }\n array.length = size;\n return array;\n }\n\n /**\n * Converts `string` to a property path array.\n *\n * @private\n * @param {string} string The string to convert.\n * @returns {Array} Returns the property path array.\n */\n var stringToPath = memoizeCapped(function(string) {\n var result = [];\n if (string.charCodeAt(0) === 46 /* . */) {\n result.push('');\n }\n string.replace(rePropName, function(match, number, quote, subString) {\n result.push(quote ? subString.replace(reEscapeChar, '$1') : (number || match));\n });\n return result;\n });\n\n /**\n * Converts `value` to a string key if it's not a string or symbol.\n *\n * @private\n * @param {*} value The value to inspect.\n * @returns {string|symbol} Returns the key.\n */\n function toKey(value) {\n if (typeof value == 'string' || isSymbol(value)) {\n return value;\n }\n var result = (value + '');\n return (result == '0' && (1 / value) == -INFINITY) ? '-0' : result;\n }\n\n /**\n * Converts `func` to its source code.\n *\n * @private\n * @param {Function} func The function to convert.\n * @returns {string} Returns the source code.\n */\n function toSource(func) {\n if (func != null) {\n try {\n return funcToString.call(func);\n } catch (e) {}\n try {\n return (func + '');\n } catch (e) {}\n }\n return '';\n }\n\n /**\n * Updates wrapper `details` based on `bitmask` flags.\n *\n * @private\n * @returns {Array} details The details to modify.\n * @param {number} bitmask The bitmask flags. See `createWrap` for more details.\n * @returns {Array} Returns `details`.\n */\n function updateWrapDetails(details, bitmask) {\n arrayEach(wrapFlags, function(pair) {\n var value = '_.' + pair[0];\n if ((bitmask & pair[1]) && !arrayIncludes(details, value)) {\n details.push(value);\n }\n });\n return details.sort();\n }\n\n /**\n * Creates a clone of `wrapper`.\n *\n * @private\n * @param {Object} wrapper The wrapper to clone.\n * @returns {Object} Returns the cloned wrapper.\n */\n function wrapperClone(wrapper) {\n if (wrapper instanceof LazyWrapper) {\n return wrapper.clone();\n }\n var result = new LodashWrapper(wrapper.__wrapped__, wrapper.__chain__);\n result.__actions__ = copyArray(wrapper.__actions__);\n result.__index__ = wrapper.__index__;\n result.__values__ = wrapper.__values__;\n return result;\n }\n\n /*------------------------------------------------------------------------*/\n\n /**\n * Creates an array of elements split into groups the length of `size`.\n * If `array` can't be split evenly, the final chunk will be the remaining\n * elements.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Array\n * @param {Array} array The array to process.\n * @param {number} [size=1] The length of each chunk\n * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.\n * @returns {Array} Returns the new array of chunks.\n * @example\n *\n * _.chunk(['a', 'b', 'c', 'd'], 2);\n * // => [['a', 'b'], ['c', 'd']]\n *\n * _.chunk(['a', 'b', 'c', 'd'], 3);\n * // => [['a', 'b', 'c'], ['d']]\n */\n function chunk(array, size, guard) {\n if ((guard ? isIterateeCall(array, size, guard) : size === undefined)) {\n size = 1;\n } else {\n size = nativeMax(toInteger(size), 0);\n }\n var length = array == null ? 0 : array.length;\n if (!length || size < 1) {\n return [];\n }\n var index = 0,\n resIndex = 0,\n result = Array(nativeCeil(length / size));\n\n while (index < length) {\n result[resIndex++] = baseSlice(array, index, (index += size));\n }\n return result;\n }\n\n /**\n * Creates an array with all falsey values removed. The values `false`, `null`,\n * `0`, `\"\"`, `undefined`, and `NaN` are falsey.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Array\n * @param {Array} array The array to compact.\n * @returns {Array} Returns the new array of filtered values.\n * @example\n *\n * _.compact([0, 1, false, 2, '', 3]);\n * // => [1, 2, 3]\n */\n function compact(array) {\n var index = -1,\n length = array == null ? 0 : array.length,\n resIndex = 0,\n result = [];\n\n while (++index < length) {\n var value = array[index];\n if (value) {\n result[resIndex++] = value;\n }\n }\n return result;\n }\n\n /**\n * Creates a new array concatenating `array` with any additional arrays\n * and/or values.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {Array} array The array to concatenate.\n * @param {...*} [values] The values to concatenate.\n * @returns {Array} Returns the new concatenated array.\n * @example\n *\n * var array = [1];\n * var other = _.concat(array, 2, [3], [[4]]);\n *\n * console.log(other);\n * // => [1, 2, 3, [4]]\n *\n * console.log(array);\n * // => [1]\n */\n function concat() {\n var length = arguments.length;\n if (!length) {\n return [];\n }\n var args = Array(length - 1),\n array = arguments[0],\n index = length;\n\n while (index--) {\n args[index - 1] = arguments[index];\n }\n return arrayPush(isArray(array) ? copyArray(array) : [array], baseFlatten(args, 1));\n }\n\n /**\n * Creates an array of `array` values not included in the other given arrays\n * using [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)\n * for equality comparisons. The order and references of result values are\n * determined by the first array.\n *\n * **Note:** Unlike `_.pullAll`, this method returns a new array.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Array\n * @param {Array} array The array to inspect.\n * @param {...Array} [values] The values to exclude.\n * @returns {Array} Returns the new array of filtered values.\n * @see _.without, _.xor\n * @example\n *\n * _.difference([2, 1], [2, 3]);\n * // => [1]\n */\n var difference = baseRest(function(array, values) {\n return isArrayLikeObject(array)\n ? baseDifference(array, baseFlatten(values, 1, isArrayLikeObject, true))\n : [];\n });\n\n /**\n * This method is like `_.difference` except that it accepts `iteratee` which\n * is invoked for each element of `array` and `values` to generate the criterion\n * by which they're compared. The order and references of result values are\n * determined by the first array. The iteratee is invoked with one argument:\n * (value).\n *\n * **Note:** Unlike `_.pullAllBy`, this method returns a new array.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {Array} array The array to inspect.\n * @param {...Array} [values] The values to exclude.\n * @param {Function} [iteratee=_.identity] The iteratee invoked per element.\n * @returns {Array} Returns the new array of filtered values.\n * @example\n *\n * _.differenceBy([2.1, 1.2], [2.3, 3.4], Math.floor);\n * // => [1.2]\n *\n * // The `_.property` iteratee shorthand.\n * _.differenceBy([{ 'x': 2 }, { 'x': 1 }], [{ 'x': 1 }], 'x');\n * // => [{ 'x': 2 }]\n */\n var differenceBy = baseRest(function(array, values) {\n var iteratee = last(values);\n if (isArrayLikeObject(iteratee)) {\n iteratee = undefined;\n }\n return isArrayLikeObject(array)\n ? baseDifference(array, baseFlatten(values, 1, isArrayLikeObject, true), getIteratee(iteratee, 2))\n : [];\n });\n\n /**\n * This method is like `_.difference` except that it accepts `comparator`\n * which is invoked to compare elements of `array` to `values`. The order and\n * references of result values are determined by the first array. The comparator\n * is invoked with two arguments: (arrVal, othVal).\n *\n * **Note:** Unlike `_.pullAllWith`, this method returns a new array.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {Array} array The array to inspect.\n * @param {...Array} [values] The values to exclude.\n * @param {Function} [comparator] The comparator invoked per element.\n * @returns {Array} Returns the new array of filtered values.\n * @example\n *\n * var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }];\n *\n * _.differenceWith(objects, [{ 'x': 1, 'y': 2 }], _.isEqual);\n * // => [{ 'x': 2, 'y': 1 }]\n */\n var differenceWith = baseRest(function(array, values) {\n var comparator = last(values);\n if (isArrayLikeObject(comparator)) {\n comparator = undefined;\n }\n return isArrayLikeObject(array)\n ? baseDifference(array, baseFlatten(values, 1, isArrayLikeObject, true), undefined, comparator)\n : [];\n });\n\n /**\n * Creates a slice of `array` with `n` elements dropped from the beginning.\n *\n * @static\n * @memberOf _\n * @since 0.5.0\n * @category Array\n * @param {Array} array The array to query.\n * @param {number} [n=1] The number of elements to drop.\n * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.\n * @returns {Array} Returns the slice of `array`.\n * @example\n *\n * _.drop([1, 2, 3]);\n * // => [2, 3]\n *\n * _.drop([1, 2, 3], 2);\n * // => [3]\n *\n * _.drop([1, 2, 3], 5);\n * // => []\n *\n * _.drop([1, 2, 3], 0);\n * // => [1, 2, 3]\n */\n function drop(array, n, guard) {\n var length = array == null ? 0 : array.length;\n if (!length) {\n return [];\n }\n n = (guard || n === undefined) ? 1 : toInteger(n);\n return baseSlice(array, n < 0 ? 0 : n, length);\n }\n\n /**\n * Creates a slice of `array` with `n` elements dropped from the end.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Array\n * @param {Array} array The array to query.\n * @param {number} [n=1] The number of elements to drop.\n * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.\n * @returns {Array} Returns the slice of `array`.\n * @example\n *\n * _.dropRight([1, 2, 3]);\n * // => [1, 2]\n *\n * _.dropRight([1, 2, 3], 2);\n * // => [1]\n *\n * _.dropRight([1, 2, 3], 5);\n * // => []\n *\n * _.dropRight([1, 2, 3], 0);\n * // => [1, 2, 3]\n */\n function dropRight(array, n, guard) {\n var length = array == null ? 0 : array.length;\n if (!length) {\n return [];\n }\n n = (guard || n === undefined) ? 1 : toInteger(n);\n n = length - n;\n return baseSlice(array, 0, n < 0 ? 0 : n);\n }\n\n /**\n * Creates a slice of `array` excluding elements dropped from the end.\n * Elements are dropped until `predicate` returns falsey. The predicate is\n * invoked with three arguments: (value, index, array).\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Array\n * @param {Array} array The array to query.\n * @param {Function} [predicate=_.identity] The function invoked per iteration.\n * @returns {Array} Returns the slice of `array`.\n * @example\n *\n * var users = [\n * { 'user': 'barney', 'active': true },\n * { 'user': 'fred', 'active': false },\n * { 'user': 'pebbles', 'active': false }\n * ];\n *\n * _.dropRightWhile(users, function(o) { return !o.active; });\n * // => objects for ['barney']\n *\n * // The `_.matches` iteratee shorthand.\n * _.dropRightWhile(users, { 'user': 'pebbles', 'active': false });\n * // => objects for ['barney', 'fred']\n *\n * // The `_.matchesProperty` iteratee shorthand.\n * _.dropRightWhile(users, ['active', false]);\n * // => objects for ['barney']\n *\n * // The `_.property` iteratee shorthand.\n * _.dropRightWhile(users, 'active');\n * // => objects for ['barney', 'fred', 'pebbles']\n */\n function dropRightWhile(array, predicate) {\n return (array && array.length)\n ? baseWhile(array, getIteratee(predicate, 3), true, true)\n : [];\n }\n\n /**\n * Creates a slice of `array` excluding elements dropped from the beginning.\n * Elements are dropped until `predicate` returns falsey. The predicate is\n * invoked with three arguments: (value, index, array).\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Array\n * @param {Array} array The array to query.\n * @param {Function} [predicate=_.identity] The function invoked per iteration.\n * @returns {Array} Returns the slice of `array`.\n * @example\n *\n * var users = [\n * { 'user': 'barney', 'active': false },\n * { 'user': 'fred', 'active': false },\n * { 'user': 'pebbles', 'active': true }\n * ];\n *\n * _.dropWhile(users, function(o) { return !o.active; });\n * // => objects for ['pebbles']\n *\n * // The `_.matches` iteratee shorthand.\n * _.dropWhile(users, { 'user': 'barney', 'active': false });\n * // => objects for ['fred', 'pebbles']\n *\n * // The `_.matchesProperty` iteratee shorthand.\n * _.dropWhile(users, ['active', false]);\n * // => objects for ['pebbles']\n *\n * // The `_.property` iteratee shorthand.\n * _.dropWhile(users, 'active');\n * // => objects for ['barney', 'fred', 'pebbles']\n */\n function dropWhile(array, predicate) {\n return (array && array.length)\n ? baseWhile(array, getIteratee(predicate, 3), true)\n : [];\n }\n\n /**\n * Fills elements of `array` with `value` from `start` up to, but not\n * including, `end`.\n *\n * **Note:** This method mutates `array`.\n *\n * @static\n * @memberOf _\n * @since 3.2.0\n * @category Array\n * @param {Array} array The array to fill.\n * @param {*} value The value to fill `array` with.\n * @param {number} [start=0] The start position.\n * @param {number} [end=array.length] The end position.\n * @returns {Array} Returns `array`.\n * @example\n *\n * var array = [1, 2, 3];\n *\n * _.fill(array, 'a');\n * console.log(array);\n * // => ['a', 'a', 'a']\n *\n * _.fill(Array(3), 2);\n * // => [2, 2, 2]\n *\n * _.fill([4, 6, 8, 10], '*', 1, 3);\n * // => [4, '*', '*', 10]\n */\n function fill(array, value, start, end) {\n var length = array == null ? 0 : array.length;\n if (!length) {\n return [];\n }\n if (start && typeof start != 'number' && isIterateeCall(array, value, start)) {\n start = 0;\n end = length;\n }\n return baseFill(array, value, start, end);\n }\n\n /**\n * This method is like `_.find` except that it returns the index of the first\n * element `predicate` returns truthy for instead of the element itself.\n *\n * @static\n * @memberOf _\n * @since 1.1.0\n * @category Array\n * @param {Array} array The array to inspect.\n * @param {Function} [predicate=_.identity] The function invoked per iteration.\n * @param {number} [fromIndex=0] The index to search from.\n * @returns {number} Returns the index of the found element, else `-1`.\n * @example\n *\n * var users = [\n * { 'user': 'barney', 'active': false },\n * { 'user': 'fred', 'active': false },\n * { 'user': 'pebbles', 'active': true }\n * ];\n *\n * _.findIndex(users, function(o) { return o.user == 'barney'; });\n * // => 0\n *\n * // The `_.matches` iteratee shorthand.\n * _.findIndex(users, { 'user': 'fred', 'active': false });\n * // => 1\n *\n * // The `_.matchesProperty` iteratee shorthand.\n * _.findIndex(users, ['active', false]);\n * // => 0\n *\n * // The `_.property` iteratee shorthand.\n * _.findIndex(users, 'active');\n * // => 2\n */\n function findIndex(array, predicate, fromIndex) {\n var length = array == null ? 0 : array.length;\n if (!length) {\n return -1;\n }\n var index = fromIndex == null ? 0 : toInteger(fromIndex);\n if (index < 0) {\n index = nativeMax(length + index, 0);\n }\n return baseFindIndex(array, getIteratee(predicate, 3), index);\n }\n\n /**\n * This method is like `_.findIndex` except that it iterates over elements\n * of `collection` from right to left.\n *\n * @static\n * @memberOf _\n * @since 2.0.0\n * @category Array\n * @param {Array} array The array to inspect.\n * @param {Function} [predicate=_.identity] The function invoked per iteration.\n * @param {number} [fromIndex=array.length-1] The index to search from.\n * @returns {number} Returns the index of the found element, else `-1`.\n * @example\n *\n * var users = [\n * { 'user': 'barney', 'active': true },\n * { 'user': 'fred', 'active': false },\n * { 'user': 'pebbles', 'active': false }\n * ];\n *\n * _.findLastIndex(users, function(o) { return o.user == 'pebbles'; });\n * // => 2\n *\n * // The `_.matches` iteratee shorthand.\n * _.findLastIndex(users, { 'user': 'barney', 'active': true });\n * // => 0\n *\n * // The `_.matchesProperty` iteratee shorthand.\n * _.findLastIndex(users, ['active', false]);\n * // => 2\n *\n * // The `_.property` iteratee shorthand.\n * _.findLastIndex(users, 'active');\n * // => 0\n */\n function findLastIndex(array, predicate, fromIndex) {\n var length = array == null ? 0 : array.length;\n if (!length) {\n return -1;\n }\n var index = length - 1;\n if (fromIndex !== undefined) {\n index = toInteger(fromIndex);\n index = fromIndex < 0\n ? nativeMax(length + index, 0)\n : nativeMin(index, length - 1);\n }\n return baseFindIndex(array, getIteratee(predicate, 3), index, true);\n }\n\n /**\n * Flattens `array` a single level deep.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Array\n * @param {Array} array The array to flatten.\n * @returns {Array} Returns the new flattened array.\n * @example\n *\n * _.flatten([1, [2, [3, [4]], 5]]);\n * // => [1, 2, [3, [4]], 5]\n */\n function flatten(array) {\n var length = array == null ? 0 : array.length;\n return length ? baseFlatten(array, 1) : [];\n }\n\n /**\n * Recursively flattens `array`.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Array\n * @param {Array} array The array to flatten.\n * @returns {Array} Returns the new flattened array.\n * @example\n *\n * _.flattenDeep([1, [2, [3, [4]], 5]]);\n * // => [1, 2, 3, 4, 5]\n */\n function flattenDeep(array) {\n var length = array == null ? 0 : array.length;\n return length ? baseFlatten(array, INFINITY) : [];\n }\n\n /**\n * Recursively flatten `array` up to `depth` times.\n *\n * @static\n * @memberOf _\n * @since 4.4.0\n * @category Array\n * @param {Array} array The array to flatten.\n * @param {number} [depth=1] The maximum recursion depth.\n * @returns {Array} Returns the new flattened array.\n * @example\n *\n * var array = [1, [2, [3, [4]], 5]];\n *\n * _.flattenDepth(array, 1);\n * // => [1, 2, [3, [4]], 5]\n *\n * _.flattenDepth(array, 2);\n * // => [1, 2, 3, [4], 5]\n */\n function flattenDepth(array, depth) {\n var length = array == null ? 0 : array.length;\n if (!length) {\n return [];\n }\n depth = depth === undefined ? 1 : toInteger(depth);\n return baseFlatten(array, depth);\n }\n\n /**\n * The inverse of `_.toPairs`; this method returns an object composed\n * from key-value `pairs`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {Array} pairs The key-value pairs.\n * @returns {Object} Returns the new object.\n * @example\n *\n * _.fromPairs([['a', 1], ['b', 2]]);\n * // => { 'a': 1, 'b': 2 }\n */\n function fromPairs(pairs) {\n var index = -1,\n length = pairs == null ? 0 : pairs.length,\n result = {};\n\n while (++index < length) {\n var pair = pairs[index];\n result[pair[0]] = pair[1];\n }\n return result;\n }\n\n /**\n * Gets the first element of `array`.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @alias first\n * @category Array\n * @param {Array} array The array to query.\n * @returns {*} Returns the first element of `array`.\n * @example\n *\n * _.head([1, 2, 3]);\n * // => 1\n *\n * _.head([]);\n * // => undefined\n */\n function head(array) {\n return (array && array.length) ? array[0] : undefined;\n }\n\n /**\n * Gets the index at which the first occurrence of `value` is found in `array`\n * using [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)\n * for equality comparisons. If `fromIndex` is negative, it's used as the\n * offset from the end of `array`.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Array\n * @param {Array} array The array to inspect.\n * @param {*} value The value to search for.\n * @param {number} [fromIndex=0] The index to search from.\n * @returns {number} Returns the index of the matched value, else `-1`.\n * @example\n *\n * _.indexOf([1, 2, 1, 2], 2);\n * // => 1\n *\n * // Search from the `fromIndex`.\n * _.indexOf([1, 2, 1, 2], 2, 2);\n * // => 3\n */\n function indexOf(array, value, fromIndex) {\n var length = array == null ? 0 : array.length;\n if (!length) {\n return -1;\n }\n var index = fromIndex == null ? 0 : toInteger(fromIndex);\n if (index < 0) {\n index = nativeMax(length + index, 0);\n }\n return baseIndexOf(array, value, index);\n }\n\n /**\n * Gets all but the last element of `array`.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Array\n * @param {Array} array The array to query.\n * @returns {Array} Returns the slice of `array`.\n * @example\n *\n * _.initial([1, 2, 3]);\n * // => [1, 2]\n */\n function initial(array) {\n var length = array == null ? 0 : array.length;\n return length ? baseSlice(array, 0, -1) : [];\n }\n\n /**\n * Creates an array of unique values that are included in all given arrays\n * using [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)\n * for equality comparisons. The order and references of result values are\n * determined by the first array.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Array\n * @param {...Array} [arrays] The arrays to inspect.\n * @returns {Array} Returns the new array of intersecting values.\n * @example\n *\n * _.intersection([2, 1], [2, 3]);\n * // => [2]\n */\n var intersection = baseRest(function(arrays) {\n var mapped = arrayMap(arrays, castArrayLikeObject);\n return (mapped.length && mapped[0] === arrays[0])\n ? baseIntersection(mapped)\n : [];\n });\n\n /**\n * This method is like `_.intersection` except that it accepts `iteratee`\n * which is invoked for each element of each `arrays` to generate the criterion\n * by which they're compared. The order and references of result values are\n * determined by the first array. The iteratee is invoked with one argument:\n * (value).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {...Array} [arrays] The arrays to inspect.\n * @param {Function} [iteratee=_.identity] The iteratee invoked per element.\n * @returns {Array} Returns the new array of intersecting values.\n * @example\n *\n * _.intersectionBy([2.1, 1.2], [2.3, 3.4], Math.floor);\n * // => [2.1]\n *\n * // The `_.property` iteratee shorthand.\n * _.intersectionBy([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x');\n * // => [{ 'x': 1 }]\n */\n var intersectionBy = baseRest(function(arrays) {\n var iteratee = last(arrays),\n mapped = arrayMap(arrays, castArrayLikeObject);\n\n if (iteratee === last(mapped)) {\n iteratee = undefined;\n } else {\n mapped.pop();\n }\n return (mapped.length && mapped[0] === arrays[0])\n ? baseIntersection(mapped, getIteratee(iteratee, 2))\n : [];\n });\n\n /**\n * This method is like `_.intersection` except that it accepts `comparator`\n * which is invoked to compare elements of `arrays`. The order and references\n * of result values are determined by the first array. The comparator is\n * invoked with two arguments: (arrVal, othVal).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {...Array} [arrays] The arrays to inspect.\n * @param {Function} [comparator] The comparator invoked per element.\n * @returns {Array} Returns the new array of intersecting values.\n * @example\n *\n * var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }];\n * var others = [{ 'x': 1, 'y': 1 }, { 'x': 1, 'y': 2 }];\n *\n * _.intersectionWith(objects, others, _.isEqual);\n * // => [{ 'x': 1, 'y': 2 }]\n */\n var intersectionWith = baseRest(function(arrays) {\n var comparator = last(arrays),\n mapped = arrayMap(arrays, castArrayLikeObject);\n\n comparator = typeof comparator == 'function' ? comparator : undefined;\n if (comparator) {\n mapped.pop();\n }\n return (mapped.length && mapped[0] === arrays[0])\n ? baseIntersection(mapped, undefined, comparator)\n : [];\n });\n\n /**\n * Converts all elements in `array` into a string separated by `separator`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {Array} array The array to convert.\n * @param {string} [separator=','] The element separator.\n * @returns {string} Returns the joined string.\n * @example\n *\n * _.join(['a', 'b', 'c'], '~');\n * // => 'a~b~c'\n */\n function join(array, separator) {\n return array == null ? '' : nativeJoin.call(array, separator);\n }\n\n /**\n * Gets the last element of `array`.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Array\n * @param {Array} array The array to query.\n * @returns {*} Returns the last element of `array`.\n * @example\n *\n * _.last([1, 2, 3]);\n * // => 3\n */\n function last(array) {\n var length = array == null ? 0 : array.length;\n return length ? array[length - 1] : undefined;\n }\n\n /**\n * This method is like `_.indexOf` except that it iterates over elements of\n * `array` from right to left.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Array\n * @param {Array} array The array to inspect.\n * @param {*} value The value to search for.\n * @param {number} [fromIndex=array.length-1] The index to search from.\n * @returns {number} Returns the index of the matched value, else `-1`.\n * @example\n *\n * _.lastIndexOf([1, 2, 1, 2], 2);\n * // => 3\n *\n * // Search from the `fromIndex`.\n * _.lastIndexOf([1, 2, 1, 2], 2, 2);\n * // => 1\n */\n function lastIndexOf(array, value, fromIndex) {\n var length = array == null ? 0 : array.length;\n if (!length) {\n return -1;\n }\n var index = length;\n if (fromIndex !== undefined) {\n index = toInteger(fromIndex);\n index = index < 0 ? nativeMax(length + index, 0) : nativeMin(index, length - 1);\n }\n return value === value\n ? strictLastIndexOf(array, value, index)\n : baseFindIndex(array, baseIsNaN, index, true);\n }\n\n /**\n * Gets the element at index `n` of `array`. If `n` is negative, the nth\n * element from the end is returned.\n *\n * @static\n * @memberOf _\n * @since 4.11.0\n * @category Array\n * @param {Array} array The array to query.\n * @param {number} [n=0] The index of the element to return.\n * @returns {*} Returns the nth element of `array`.\n * @example\n *\n * var array = ['a', 'b', 'c', 'd'];\n *\n * _.nth(array, 1);\n * // => 'b'\n *\n * _.nth(array, -2);\n * // => 'c';\n */\n function nth(array, n) {\n return (array && array.length) ? baseNth(array, toInteger(n)) : undefined;\n }\n\n /**\n * Removes all given values from `array` using\n * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)\n * for equality comparisons.\n *\n * **Note:** Unlike `_.without`, this method mutates `array`. Use `_.remove`\n * to remove elements from an array by predicate.\n *\n * @static\n * @memberOf _\n * @since 2.0.0\n * @category Array\n * @param {Array} array The array to modify.\n * @param {...*} [values] The values to remove.\n * @returns {Array} Returns `array`.\n * @example\n *\n * var array = ['a', 'b', 'c', 'a', 'b', 'c'];\n *\n * _.pull(array, 'a', 'c');\n * console.log(array);\n * // => ['b', 'b']\n */\n var pull = baseRest(pullAll);\n\n /**\n * This method is like `_.pull` except that it accepts an array of values to remove.\n *\n * **Note:** Unlike `_.difference`, this method mutates `array`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {Array} array The array to modify.\n * @param {Array} values The values to remove.\n * @returns {Array} Returns `array`.\n * @example\n *\n * var array = ['a', 'b', 'c', 'a', 'b', 'c'];\n *\n * _.pullAll(array, ['a', 'c']);\n * console.log(array);\n * // => ['b', 'b']\n */\n function pullAll(array, values) {\n return (array && array.length && values && values.length)\n ? basePullAll(array, values)\n : array;\n }\n\n /**\n * This method is like `_.pullAll` except that it accepts `iteratee` which is\n * invoked for each element of `array` and `values` to generate the criterion\n * by which they're compared. The iteratee is invoked with one argument: (value).\n *\n * **Note:** Unlike `_.differenceBy`, this method mutates `array`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {Array} array The array to modify.\n * @param {Array} values The values to remove.\n * @param {Function} [iteratee=_.identity] The iteratee invoked per element.\n * @returns {Array} Returns `array`.\n * @example\n *\n * var array = [{ 'x': 1 }, { 'x': 2 }, { 'x': 3 }, { 'x': 1 }];\n *\n * _.pullAllBy(array, [{ 'x': 1 }, { 'x': 3 }], 'x');\n * console.log(array);\n * // => [{ 'x': 2 }]\n */\n function pullAllBy(array, values, iteratee) {\n return (array && array.length && values && values.length)\n ? basePullAll(array, values, getIteratee(iteratee, 2))\n : array;\n }\n\n /**\n * This method is like `_.pullAll` except that it accepts `comparator` which\n * is invoked to compare elements of `array` to `values`. The comparator is\n * invoked with two arguments: (arrVal, othVal).\n *\n * **Note:** Unlike `_.differenceWith`, this method mutates `array`.\n *\n * @static\n * @memberOf _\n * @since 4.6.0\n * @category Array\n * @param {Array} array The array to modify.\n * @param {Array} values The values to remove.\n * @param {Function} [comparator] The comparator invoked per element.\n * @returns {Array} Returns `array`.\n * @example\n *\n * var array = [{ 'x': 1, 'y': 2 }, { 'x': 3, 'y': 4 }, { 'x': 5, 'y': 6 }];\n *\n * _.pullAllWith(array, [{ 'x': 3, 'y': 4 }], _.isEqual);\n * console.log(array);\n * // => [{ 'x': 1, 'y': 2 }, { 'x': 5, 'y': 6 }]\n */\n function pullAllWith(array, values, comparator) {\n return (array && array.length && values && values.length)\n ? basePullAll(array, values, undefined, comparator)\n : array;\n }\n\n /**\n * Removes elements from `array` corresponding to `indexes` and returns an\n * array of removed elements.\n *\n * **Note:** Unlike `_.at`, this method mutates `array`.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Array\n * @param {Array} array The array to modify.\n * @param {...(number|number[])} [indexes] The indexes of elements to remove.\n * @returns {Array} Returns the new array of removed elements.\n * @example\n *\n * var array = ['a', 'b', 'c', 'd'];\n * var pulled = _.pullAt(array, [1, 3]);\n *\n * console.log(array);\n * // => ['a', 'c']\n *\n * console.log(pulled);\n * // => ['b', 'd']\n */\n var pullAt = flatRest(function(array, indexes) {\n var length = array == null ? 0 : array.length,\n result = baseAt(array, indexes);\n\n basePullAt(array, arrayMap(indexes, function(index) {\n return isIndex(index, length) ? +index : index;\n }).sort(compareAscending));\n\n return result;\n });\n\n /**\n * Removes all elements from `array` that `predicate` returns truthy for\n * and returns an array of the removed elements. The predicate is invoked\n * with three arguments: (value, index, array).\n *\n * **Note:** Unlike `_.filter`, this method mutates `array`. Use `_.pull`\n * to pull elements from an array by value.\n *\n * @static\n * @memberOf _\n * @since 2.0.0\n * @category Array\n * @param {Array} array The array to modify.\n * @param {Function} [predicate=_.identity] The function invoked per iteration.\n * @returns {Array} Returns the new array of removed elements.\n * @example\n *\n * var array = [1, 2, 3, 4];\n * var evens = _.remove(array, function(n) {\n * return n % 2 == 0;\n * });\n *\n * console.log(array);\n * // => [1, 3]\n *\n * console.log(evens);\n * // => [2, 4]\n */\n function remove(array, predicate) {\n var result = [];\n if (!(array && array.length)) {\n return result;\n }\n var index = -1,\n indexes = [],\n length = array.length;\n\n predicate = getIteratee(predicate, 3);\n while (++index < length) {\n var value = array[index];\n if (predicate(value, index, array)) {\n result.push(value);\n indexes.push(index);\n }\n }\n basePullAt(array, indexes);\n return result;\n }\n\n /**\n * Reverses `array` so that the first element becomes the last, the second\n * element becomes the second to last, and so on.\n *\n * **Note:** This method mutates `array` and is based on\n * [`Array#reverse`](https://mdn.io/Array/reverse).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {Array} array The array to modify.\n * @returns {Array} Returns `array`.\n * @example\n *\n * var array = [1, 2, 3];\n *\n * _.reverse(array);\n * // => [3, 2, 1]\n *\n * console.log(array);\n * // => [3, 2, 1]\n */\n function reverse(array) {\n return array == null ? array : nativeReverse.call(array);\n }\n\n /**\n * Creates a slice of `array` from `start` up to, but not including, `end`.\n *\n * **Note:** This method is used instead of\n * [`Array#slice`](https://mdn.io/Array/slice) to ensure dense arrays are\n * returned.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Array\n * @param {Array} array The array to slice.\n * @param {number} [start=0] The start position.\n * @param {number} [end=array.length] The end position.\n * @returns {Array} Returns the slice of `array`.\n */\n function slice(array, start, end) {\n var length = array == null ? 0 : array.length;\n if (!length) {\n return [];\n }\n if (end && typeof end != 'number' && isIterateeCall(array, start, end)) {\n start = 0;\n end = length;\n }\n else {\n start = start == null ? 0 : toInteger(start);\n end = end === undefined ? length : toInteger(end);\n }\n return baseSlice(array, start, end);\n }\n\n /**\n * Uses a binary search to determine the lowest index at which `value`\n * should be inserted into `array` in order to maintain its sort order.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Array\n * @param {Array} array The sorted array to inspect.\n * @param {*} value The value to evaluate.\n * @returns {number} Returns the index at which `value` should be inserted\n * into `array`.\n * @example\n *\n * _.sortedIndex([30, 50], 40);\n * // => 1\n */\n function sortedIndex(array, value) {\n return baseSortedIndex(array, value);\n }\n\n /**\n * This method is like `_.sortedIndex` except that it accepts `iteratee`\n * which is invoked for `value` and each element of `array` to compute their\n * sort ranking. The iteratee is invoked with one argument: (value).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {Array} array The sorted array to inspect.\n * @param {*} value The value to evaluate.\n * @param {Function} [iteratee=_.identity] The iteratee invoked per element.\n * @returns {number} Returns the index at which `value` should be inserted\n * into `array`.\n * @example\n *\n * var objects = [{ 'x': 4 }, { 'x': 5 }];\n *\n * _.sortedIndexBy(objects, { 'x': 4 }, function(o) { return o.x; });\n * // => 0\n *\n * // The `_.property` iteratee shorthand.\n * _.sortedIndexBy(objects, { 'x': 4 }, 'x');\n * // => 0\n */\n function sortedIndexBy(array, value, iteratee) {\n return baseSortedIndexBy(array, value, getIteratee(iteratee, 2));\n }\n\n /**\n * This method is like `_.indexOf` except that it performs a binary\n * search on a sorted `array`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {Array} array The array to inspect.\n * @param {*} value The value to search for.\n * @returns {number} Returns the index of the matched value, else `-1`.\n * @example\n *\n * _.sortedIndexOf([4, 5, 5, 5, 6], 5);\n * // => 1\n */\n function sortedIndexOf(array, value) {\n var length = array == null ? 0 : array.length;\n if (length) {\n var index = baseSortedIndex(array, value);\n if (index < length && eq(array[index], value)) {\n return index;\n }\n }\n return -1;\n }\n\n /**\n * This method is like `_.sortedIndex` except that it returns the highest\n * index at which `value` should be inserted into `array` in order to\n * maintain its sort order.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Array\n * @param {Array} array The sorted array to inspect.\n * @param {*} value The value to evaluate.\n * @returns {number} Returns the index at which `value` should be inserted\n * into `array`.\n * @example\n *\n * _.sortedLastIndex([4, 5, 5, 5, 6], 5);\n * // => 4\n */\n function sortedLastIndex(array, value) {\n return baseSortedIndex(array, value, true);\n }\n\n /**\n * This method is like `_.sortedLastIndex` except that it accepts `iteratee`\n * which is invoked for `value` and each element of `array` to compute their\n * sort ranking. The iteratee is invoked with one argument: (value).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {Array} array The sorted array to inspect.\n * @param {*} value The value to evaluate.\n * @param {Function} [iteratee=_.identity] The iteratee invoked per element.\n * @returns {number} Returns the index at which `value` should be inserted\n * into `array`.\n * @example\n *\n * var objects = [{ 'x': 4 }, { 'x': 5 }];\n *\n * _.sortedLastIndexBy(objects, { 'x': 4 }, function(o) { return o.x; });\n * // => 1\n *\n * // The `_.property` iteratee shorthand.\n * _.sortedLastIndexBy(objects, { 'x': 4 }, 'x');\n * // => 1\n */\n function sortedLastIndexBy(array, value, iteratee) {\n return baseSortedIndexBy(array, value, getIteratee(iteratee, 2), true);\n }\n\n /**\n * This method is like `_.lastIndexOf` except that it performs a binary\n * search on a sorted `array`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {Array} array The array to inspect.\n * @param {*} value The value to search for.\n * @returns {number} Returns the index of the matched value, else `-1`.\n * @example\n *\n * _.sortedLastIndexOf([4, 5, 5, 5, 6], 5);\n * // => 3\n */\n function sortedLastIndexOf(array, value) {\n var length = array == null ? 0 : array.length;\n if (length) {\n var index = baseSortedIndex(array, value, true) - 1;\n if (eq(array[index], value)) {\n return index;\n }\n }\n return -1;\n }\n\n /**\n * This method is like `_.uniq` except that it's designed and optimized\n * for sorted arrays.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {Array} array The array to inspect.\n * @returns {Array} Returns the new duplicate free array.\n * @example\n *\n * _.sortedUniq([1, 1, 2]);\n * // => [1, 2]\n */\n function sortedUniq(array) {\n return (array && array.length)\n ? baseSortedUniq(array)\n : [];\n }\n\n /**\n * This method is like `_.uniqBy` except that it's designed and optimized\n * for sorted arrays.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {Array} array The array to inspect.\n * @param {Function} [iteratee] The iteratee invoked per element.\n * @returns {Array} Returns the new duplicate free array.\n * @example\n *\n * _.sortedUniqBy([1.1, 1.2, 2.3, 2.4], Math.floor);\n * // => [1.1, 2.3]\n */\n function sortedUniqBy(array, iteratee) {\n return (array && array.length)\n ? baseSortedUniq(array, getIteratee(iteratee, 2))\n : [];\n }\n\n /**\n * Gets all but the first element of `array`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {Array} array The array to query.\n * @returns {Array} Returns the slice of `array`.\n * @example\n *\n * _.tail([1, 2, 3]);\n * // => [2, 3]\n */\n function tail(array) {\n var length = array == null ? 0 : array.length;\n return length ? baseSlice(array, 1, length) : [];\n }\n\n /**\n * Creates a slice of `array` with `n` elements taken from the beginning.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Array\n * @param {Array} array The array to query.\n * @param {number} [n=1] The number of elements to take.\n * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.\n * @returns {Array} Returns the slice of `array`.\n * @example\n *\n * _.take([1, 2, 3]);\n * // => [1]\n *\n * _.take([1, 2, 3], 2);\n * // => [1, 2]\n *\n * _.take([1, 2, 3], 5);\n * // => [1, 2, 3]\n *\n * _.take([1, 2, 3], 0);\n * // => []\n */\n function take(array, n, guard) {\n if (!(array && array.length)) {\n return [];\n }\n n = (guard || n === undefined) ? 1 : toInteger(n);\n return baseSlice(array, 0, n < 0 ? 0 : n);\n }\n\n /**\n * Creates a slice of `array` with `n` elements taken from the end.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Array\n * @param {Array} array The array to query.\n * @param {number} [n=1] The number of elements to take.\n * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.\n * @returns {Array} Returns the slice of `array`.\n * @example\n *\n * _.takeRight([1, 2, 3]);\n * // => [3]\n *\n * _.takeRight([1, 2, 3], 2);\n * // => [2, 3]\n *\n * _.takeRight([1, 2, 3], 5);\n * // => [1, 2, 3]\n *\n * _.takeRight([1, 2, 3], 0);\n * // => []\n */\n function takeRight(array, n, guard) {\n var length = array == null ? 0 : array.length;\n if (!length) {\n return [];\n }\n n = (guard || n === undefined) ? 1 : toInteger(n);\n n = length - n;\n return baseSlice(array, n < 0 ? 0 : n, length);\n }\n\n /**\n * Creates a slice of `array` with elements taken from the end. Elements are\n * taken until `predicate` returns falsey. The predicate is invoked with\n * three arguments: (value, index, array).\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Array\n * @param {Array} array The array to query.\n * @param {Function} [predicate=_.identity] The function invoked per iteration.\n * @returns {Array} Returns the slice of `array`.\n * @example\n *\n * var users = [\n * { 'user': 'barney', 'active': true },\n * { 'user': 'fred', 'active': false },\n * { 'user': 'pebbles', 'active': false }\n * ];\n *\n * _.takeRightWhile(users, function(o) { return !o.active; });\n * // => objects for ['fred', 'pebbles']\n *\n * // The `_.matches` iteratee shorthand.\n * _.takeRightWhile(users, { 'user': 'pebbles', 'active': false });\n * // => objects for ['pebbles']\n *\n * // The `_.matchesProperty` iteratee shorthand.\n * _.takeRightWhile(users, ['active', false]);\n * // => objects for ['fred', 'pebbles']\n *\n * // The `_.property` iteratee shorthand.\n * _.takeRightWhile(users, 'active');\n * // => []\n */\n function takeRightWhile(array, predicate) {\n return (array && array.length)\n ? baseWhile(array, getIteratee(predicate, 3), false, true)\n : [];\n }\n\n /**\n * Creates a slice of `array` with elements taken from the beginning. Elements\n * are taken until `predicate` returns falsey. The predicate is invoked with\n * three arguments: (value, index, array).\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Array\n * @param {Array} array The array to query.\n * @param {Function} [predicate=_.identity] The function invoked per iteration.\n * @returns {Array} Returns the slice of `array`.\n * @example\n *\n * var users = [\n * { 'user': 'barney', 'active': false },\n * { 'user': 'fred', 'active': false },\n * { 'user': 'pebbles', 'active': true }\n * ];\n *\n * _.takeWhile(users, function(o) { return !o.active; });\n * // => objects for ['barney', 'fred']\n *\n * // The `_.matches` iteratee shorthand.\n * _.takeWhile(users, { 'user': 'barney', 'active': false });\n * // => objects for ['barney']\n *\n * // The `_.matchesProperty` iteratee shorthand.\n * _.takeWhile(users, ['active', false]);\n * // => objects for ['barney', 'fred']\n *\n * // The `_.property` iteratee shorthand.\n * _.takeWhile(users, 'active');\n * // => []\n */\n function takeWhile(array, predicate) {\n return (array && array.length)\n ? baseWhile(array, getIteratee(predicate, 3))\n : [];\n }\n\n /**\n * Creates an array of unique values, in order, from all given arrays using\n * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)\n * for equality comparisons.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Array\n * @param {...Array} [arrays] The arrays to inspect.\n * @returns {Array} Returns the new array of combined values.\n * @example\n *\n * _.union([2], [1, 2]);\n * // => [2, 1]\n */\n var union = baseRest(function(arrays) {\n return baseUniq(baseFlatten(arrays, 1, isArrayLikeObject, true));\n });\n\n /**\n * This method is like `_.union` except that it accepts `iteratee` which is\n * invoked for each element of each `arrays` to generate the criterion by\n * which uniqueness is computed. Result values are chosen from the first\n * array in which the value occurs. The iteratee is invoked with one argument:\n * (value).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {...Array} [arrays] The arrays to inspect.\n * @param {Function} [iteratee=_.identity] The iteratee invoked per element.\n * @returns {Array} Returns the new array of combined values.\n * @example\n *\n * _.unionBy([2.1], [1.2, 2.3], Math.floor);\n * // => [2.1, 1.2]\n *\n * // The `_.property` iteratee shorthand.\n * _.unionBy([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x');\n * // => [{ 'x': 1 }, { 'x': 2 }]\n */\n var unionBy = baseRest(function(arrays) {\n var iteratee = last(arrays);\n if (isArrayLikeObject(iteratee)) {\n iteratee = undefined;\n }\n return baseUniq(baseFlatten(arrays, 1, isArrayLikeObject, true), getIteratee(iteratee, 2));\n });\n\n /**\n * This method is like `_.union` except that it accepts `comparator` which\n * is invoked to compare elements of `arrays`. Result values are chosen from\n * the first array in which the value occurs. The comparator is invoked\n * with two arguments: (arrVal, othVal).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {...Array} [arrays] The arrays to inspect.\n * @param {Function} [comparator] The comparator invoked per element.\n * @returns {Array} Returns the new array of combined values.\n * @example\n *\n * var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }];\n * var others = [{ 'x': 1, 'y': 1 }, { 'x': 1, 'y': 2 }];\n *\n * _.unionWith(objects, others, _.isEqual);\n * // => [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }, { 'x': 1, 'y': 1 }]\n */\n var unionWith = baseRest(function(arrays) {\n var comparator = last(arrays);\n comparator = typeof comparator == 'function' ? comparator : undefined;\n return baseUniq(baseFlatten(arrays, 1, isArrayLikeObject, true), undefined, comparator);\n });\n\n /**\n * Creates a duplicate-free version of an array, using\n * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)\n * for equality comparisons, in which only the first occurrence of each element\n * is kept. The order of result values is determined by the order they occur\n * in the array.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Array\n * @param {Array} array The array to inspect.\n * @returns {Array} Returns the new duplicate free array.\n * @example\n *\n * _.uniq([2, 1, 2]);\n * // => [2, 1]\n */\n function uniq(array) {\n return (array && array.length) ? baseUniq(array) : [];\n }\n\n /**\n * This method is like `_.uniq` except that it accepts `iteratee` which is\n * invoked for each element in `array` to generate the criterion by which\n * uniqueness is computed. The order of result values is determined by the\n * order they occur in the array. The iteratee is invoked with one argument:\n * (value).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {Array} array The array to inspect.\n * @param {Function} [iteratee=_.identity] The iteratee invoked per element.\n * @returns {Array} Returns the new duplicate free array.\n * @example\n *\n * _.uniqBy([2.1, 1.2, 2.3], Math.floor);\n * // => [2.1, 1.2]\n *\n * // The `_.property` iteratee shorthand.\n * _.uniqBy([{ 'x': 1 }, { 'x': 2 }, { 'x': 1 }], 'x');\n * // => [{ 'x': 1 }, { 'x': 2 }]\n */\n function uniqBy(array, iteratee) {\n return (array && array.length) ? baseUniq(array, getIteratee(iteratee, 2)) : [];\n }\n\n /**\n * This method is like `_.uniq` except that it accepts `comparator` which\n * is invoked to compare elements of `array`. The order of result values is\n * determined by the order they occur in the array.The comparator is invoked\n * with two arguments: (arrVal, othVal).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {Array} array The array to inspect.\n * @param {Function} [comparator] The comparator invoked per element.\n * @returns {Array} Returns the new duplicate free array.\n * @example\n *\n * var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }, { 'x': 1, 'y': 2 }];\n *\n * _.uniqWith(objects, _.isEqual);\n * // => [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }]\n */\n function uniqWith(array, comparator) {\n comparator = typeof comparator == 'function' ? comparator : undefined;\n return (array && array.length) ? baseUniq(array, undefined, comparator) : [];\n }\n\n /**\n * This method is like `_.zip` except that it accepts an array of grouped\n * elements and creates an array regrouping the elements to their pre-zip\n * configuration.\n *\n * @static\n * @memberOf _\n * @since 1.2.0\n * @category Array\n * @param {Array} array The array of grouped elements to process.\n * @returns {Array} Returns the new array of regrouped elements.\n * @example\n *\n * var zipped = _.zip(['a', 'b'], [1, 2], [true, false]);\n * // => [['a', 1, true], ['b', 2, false]]\n *\n * _.unzip(zipped);\n * // => [['a', 'b'], [1, 2], [true, false]]\n */\n function unzip(array) {\n if (!(array && array.length)) {\n return [];\n }\n var length = 0;\n array = arrayFilter(array, function(group) {\n if (isArrayLikeObject(group)) {\n length = nativeMax(group.length, length);\n return true;\n }\n });\n return baseTimes(length, function(index) {\n return arrayMap(array, baseProperty(index));\n });\n }\n\n /**\n * This method is like `_.unzip` except that it accepts `iteratee` to specify\n * how regrouped values should be combined. The iteratee is invoked with the\n * elements of each group: (...group).\n *\n * @static\n * @memberOf _\n * @since 3.8.0\n * @category Array\n * @param {Array} array The array of grouped elements to process.\n * @param {Function} [iteratee=_.identity] The function to combine\n * regrouped values.\n * @returns {Array} Returns the new array of regrouped elements.\n * @example\n *\n * var zipped = _.zip([1, 2], [10, 20], [100, 200]);\n * // => [[1, 10, 100], [2, 20, 200]]\n *\n * _.unzipWith(zipped, _.add);\n * // => [3, 30, 300]\n */\n function unzipWith(array, iteratee) {\n if (!(array && array.length)) {\n return [];\n }\n var result = unzip(array);\n if (iteratee == null) {\n return result;\n }\n return arrayMap(result, function(group) {\n return apply(iteratee, undefined, group);\n });\n }\n\n /**\n * Creates an array excluding all given values using\n * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)\n * for equality comparisons.\n *\n * **Note:** Unlike `_.pull`, this method returns a new array.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Array\n * @param {Array} array The array to inspect.\n * @param {...*} [values] The values to exclude.\n * @returns {Array} Returns the new array of filtered values.\n * @see _.difference, _.xor\n * @example\n *\n * _.without([2, 1, 2, 3], 1, 2);\n * // => [3]\n */\n var without = baseRest(function(array, values) {\n return isArrayLikeObject(array)\n ? baseDifference(array, values)\n : [];\n });\n\n /**\n * Creates an array of unique values that is the\n * [symmetric difference](https://en.wikipedia.org/wiki/Symmetric_difference)\n * of the given arrays. The order of result values is determined by the order\n * they occur in the arrays.\n *\n * @static\n * @memberOf _\n * @since 2.4.0\n * @category Array\n * @param {...Array} [arrays] The arrays to inspect.\n * @returns {Array} Returns the new array of filtered values.\n * @see _.difference, _.without\n * @example\n *\n * _.xor([2, 1], [2, 3]);\n * // => [1, 3]\n */\n var xor = baseRest(function(arrays) {\n return baseXor(arrayFilter(arrays, isArrayLikeObject));\n });\n\n /**\n * This method is like `_.xor` except that it accepts `iteratee` which is\n * invoked for each element of each `arrays` to generate the criterion by\n * which by which they're compared. The order of result values is determined\n * by the order they occur in the arrays. The iteratee is invoked with one\n * argument: (value).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {...Array} [arrays] The arrays to inspect.\n * @param {Function} [iteratee=_.identity] The iteratee invoked per element.\n * @returns {Array} Returns the new array of filtered values.\n * @example\n *\n * _.xorBy([2.1, 1.2], [2.3, 3.4], Math.floor);\n * // => [1.2, 3.4]\n *\n * // The `_.property` iteratee shorthand.\n * _.xorBy([{ 'x': 1 }], [{ 'x': 2 }, { 'x': 1 }], 'x');\n * // => [{ 'x': 2 }]\n */\n var xorBy = baseRest(function(arrays) {\n var iteratee = last(arrays);\n if (isArrayLikeObject(iteratee)) {\n iteratee = undefined;\n }\n return baseXor(arrayFilter(arrays, isArrayLikeObject), getIteratee(iteratee, 2));\n });\n\n /**\n * This method is like `_.xor` except that it accepts `comparator` which is\n * invoked to compare elements of `arrays`. The order of result values is\n * determined by the order they occur in the arrays. The comparator is invoked\n * with two arguments: (arrVal, othVal).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Array\n * @param {...Array} [arrays] The arrays to inspect.\n * @param {Function} [comparator] The comparator invoked per element.\n * @returns {Array} Returns the new array of filtered values.\n * @example\n *\n * var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }];\n * var others = [{ 'x': 1, 'y': 1 }, { 'x': 1, 'y': 2 }];\n *\n * _.xorWith(objects, others, _.isEqual);\n * // => [{ 'x': 2, 'y': 1 }, { 'x': 1, 'y': 1 }]\n */\n var xorWith = baseRest(function(arrays) {\n var comparator = last(arrays);\n comparator = typeof comparator == 'function' ? comparator : undefined;\n return baseXor(arrayFilter(arrays, isArrayLikeObject), undefined, comparator);\n });\n\n /**\n * Creates an array of grouped elements, the first of which contains the\n * first elements of the given arrays, the second of which contains the\n * second elements of the given arrays, and so on.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Array\n * @param {...Array} [arrays] The arrays to process.\n * @returns {Array} Returns the new array of grouped elements.\n * @example\n *\n * _.zip(['a', 'b'], [1, 2], [true, false]);\n * // => [['a', 1, true], ['b', 2, false]]\n */\n var zip = baseRest(unzip);\n\n /**\n * This method is like `_.fromPairs` except that it accepts two arrays,\n * one of property identifiers and one of corresponding values.\n *\n * @static\n * @memberOf _\n * @since 0.4.0\n * @category Array\n * @param {Array} [props=[]] The property identifiers.\n * @param {Array} [values=[]] The property values.\n * @returns {Object} Returns the new object.\n * @example\n *\n * _.zipObject(['a', 'b'], [1, 2]);\n * // => { 'a': 1, 'b': 2 }\n */\n function zipObject(props, values) {\n return baseZipObject(props || [], values || [], assignValue);\n }\n\n /**\n * This method is like `_.zipObject` except that it supports property paths.\n *\n * @static\n * @memberOf _\n * @since 4.1.0\n * @category Array\n * @param {Array} [props=[]] The property identifiers.\n * @param {Array} [values=[]] The property values.\n * @returns {Object} Returns the new object.\n * @example\n *\n * _.zipObjectDeep(['a.b[0].c', 'a.b[1].d'], [1, 2]);\n * // => { 'a': { 'b': [{ 'c': 1 }, { 'd': 2 }] } }\n */\n function zipObjectDeep(props, values) {\n return baseZipObject(props || [], values || [], baseSet);\n }\n\n /**\n * This method is like `_.zip` except that it accepts `iteratee` to specify\n * how grouped values should be combined. The iteratee is invoked with the\n * elements of each group: (...group).\n *\n * @static\n * @memberOf _\n * @since 3.8.0\n * @category Array\n * @param {...Array} [arrays] The arrays to process.\n * @param {Function} [iteratee=_.identity] The function to combine\n * grouped values.\n * @returns {Array} Returns the new array of grouped elements.\n * @example\n *\n * _.zipWith([1, 2], [10, 20], [100, 200], function(a, b, c) {\n * return a + b + c;\n * });\n * // => [111, 222]\n */\n var zipWith = baseRest(function(arrays) {\n var length = arrays.length,\n iteratee = length > 1 ? arrays[length - 1] : undefined;\n\n iteratee = typeof iteratee == 'function' ? (arrays.pop(), iteratee) : undefined;\n return unzipWith(arrays, iteratee);\n });\n\n /*------------------------------------------------------------------------*/\n\n /**\n * Creates a `lodash` wrapper instance that wraps `value` with explicit method\n * chain sequences enabled. The result of such sequences must be unwrapped\n * with `_#value`.\n *\n * @static\n * @memberOf _\n * @since 1.3.0\n * @category Seq\n * @param {*} value The value to wrap.\n * @returns {Object} Returns the new `lodash` wrapper instance.\n * @example\n *\n * var users = [\n * { 'user': 'barney', 'age': 36 },\n * { 'user': 'fred', 'age': 40 },\n * { 'user': 'pebbles', 'age': 1 }\n * ];\n *\n * var youngest = _\n * .chain(users)\n * .sortBy('age')\n * .map(function(o) {\n * return o.user + ' is ' + o.age;\n * })\n * .head()\n * .value();\n * // => 'pebbles is 1'\n */\n function chain(value) {\n var result = lodash(value);\n result.__chain__ = true;\n return result;\n }\n\n /**\n * This method invokes `interceptor` and returns `value`. The interceptor\n * is invoked with one argument; (value). The purpose of this method is to\n * \"tap into\" a method chain sequence in order to modify intermediate results.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Seq\n * @param {*} value The value to provide to `interceptor`.\n * @param {Function} interceptor The function to invoke.\n * @returns {*} Returns `value`.\n * @example\n *\n * _([1, 2, 3])\n * .tap(function(array) {\n * // Mutate input array.\n * array.pop();\n * })\n * .reverse()\n * .value();\n * // => [2, 1]\n */\n function tap(value, interceptor) {\n interceptor(value);\n return value;\n }\n\n /**\n * This method is like `_.tap` except that it returns the result of `interceptor`.\n * The purpose of this method is to \"pass thru\" values replacing intermediate\n * results in a method chain sequence.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Seq\n * @param {*} value The value to provide to `interceptor`.\n * @param {Function} interceptor The function to invoke.\n * @returns {*} Returns the result of `interceptor`.\n * @example\n *\n * _(' abc ')\n * .chain()\n * .trim()\n * .thru(function(value) {\n * return [value];\n * })\n * .value();\n * // => ['abc']\n */\n function thru(value, interceptor) {\n return interceptor(value);\n }\n\n /**\n * This method is the wrapper version of `_.at`.\n *\n * @name at\n * @memberOf _\n * @since 1.0.0\n * @category Seq\n * @param {...(string|string[])} [paths] The property paths to pick.\n * @returns {Object} Returns the new `lodash` wrapper instance.\n * @example\n *\n * var object = { 'a': [{ 'b': { 'c': 3 } }, 4] };\n *\n * _(object).at(['a[0].b.c', 'a[1]']).value();\n * // => [3, 4]\n */\n var wrapperAt = flatRest(function(paths) {\n var length = paths.length,\n start = length ? paths[0] : 0,\n value = this.__wrapped__,\n interceptor = function(object) { return baseAt(object, paths); };\n\n if (length > 1 || this.__actions__.length ||\n !(value instanceof LazyWrapper) || !isIndex(start)) {\n return this.thru(interceptor);\n }\n value = value.slice(start, +start + (length ? 1 : 0));\n value.__actions__.push({\n 'func': thru,\n 'args': [interceptor],\n 'thisArg': undefined\n });\n return new LodashWrapper(value, this.__chain__).thru(function(array) {\n if (length && !array.length) {\n array.push(undefined);\n }\n return array;\n });\n });\n\n /**\n * Creates a `lodash` wrapper instance with explicit method chain sequences enabled.\n *\n * @name chain\n * @memberOf _\n * @since 0.1.0\n * @category Seq\n * @returns {Object} Returns the new `lodash` wrapper instance.\n * @example\n *\n * var users = [\n * { 'user': 'barney', 'age': 36 },\n * { 'user': 'fred', 'age': 40 }\n * ];\n *\n * // A sequence without explicit chaining.\n * _(users).head();\n * // => { 'user': 'barney', 'age': 36 }\n *\n * // A sequence with explicit chaining.\n * _(users)\n * .chain()\n * .head()\n * .pick('user')\n * .value();\n * // => { 'user': 'barney' }\n */\n function wrapperChain() {\n return chain(this);\n }\n\n /**\n * Executes the chain sequence and returns the wrapped result.\n *\n * @name commit\n * @memberOf _\n * @since 3.2.0\n * @category Seq\n * @returns {Object} Returns the new `lodash` wrapper instance.\n * @example\n *\n * var array = [1, 2];\n * var wrapped = _(array).push(3);\n *\n * console.log(array);\n * // => [1, 2]\n *\n * wrapped = wrapped.commit();\n * console.log(array);\n * // => [1, 2, 3]\n *\n * wrapped.last();\n * // => 3\n *\n * console.log(array);\n * // => [1, 2, 3]\n */\n function wrapperCommit() {\n return new LodashWrapper(this.value(), this.__chain__);\n }\n\n /**\n * Gets the next value on a wrapped object following the\n * [iterator protocol](https://mdn.io/iteration_protocols#iterator).\n *\n * @name next\n * @memberOf _\n * @since 4.0.0\n * @category Seq\n * @returns {Object} Returns the next iterator value.\n * @example\n *\n * var wrapped = _([1, 2]);\n *\n * wrapped.next();\n * // => { 'done': false, 'value': 1 }\n *\n * wrapped.next();\n * // => { 'done': false, 'value': 2 }\n *\n * wrapped.next();\n * // => { 'done': true, 'value': undefined }\n */\n function wrapperNext() {\n if (this.__values__ === undefined) {\n this.__values__ = toArray(this.value());\n }\n var done = this.__index__ >= this.__values__.length,\n value = done ? undefined : this.__values__[this.__index__++];\n\n return { 'done': done, 'value': value };\n }\n\n /**\n * Enables the wrapper to be iterable.\n *\n * @name Symbol.iterator\n * @memberOf _\n * @since 4.0.0\n * @category Seq\n * @returns {Object} Returns the wrapper object.\n * @example\n *\n * var wrapped = _([1, 2]);\n *\n * wrapped[Symbol.iterator]() === wrapped;\n * // => true\n *\n * Array.from(wrapped);\n * // => [1, 2]\n */\n function wrapperToIterator() {\n return this;\n }\n\n /**\n * Creates a clone of the chain sequence planting `value` as the wrapped value.\n *\n * @name plant\n * @memberOf _\n * @since 3.2.0\n * @category Seq\n * @param {*} value The value to plant.\n * @returns {Object} Returns the new `lodash` wrapper instance.\n * @example\n *\n * function square(n) {\n * return n * n;\n * }\n *\n * var wrapped = _([1, 2]).map(square);\n * var other = wrapped.plant([3, 4]);\n *\n * other.value();\n * // => [9, 16]\n *\n * wrapped.value();\n * // => [1, 4]\n */\n function wrapperPlant(value) {\n var result,\n parent = this;\n\n while (parent instanceof baseLodash) {\n var clone = wrapperClone(parent);\n clone.__index__ = 0;\n clone.__values__ = undefined;\n if (result) {\n previous.__wrapped__ = clone;\n } else {\n result = clone;\n }\n var previous = clone;\n parent = parent.__wrapped__;\n }\n previous.__wrapped__ = value;\n return result;\n }\n\n /**\n * This method is the wrapper version of `_.reverse`.\n *\n * **Note:** This method mutates the wrapped array.\n *\n * @name reverse\n * @memberOf _\n * @since 0.1.0\n * @category Seq\n * @returns {Object} Returns the new `lodash` wrapper instance.\n * @example\n *\n * var array = [1, 2, 3];\n *\n * _(array).reverse().value()\n * // => [3, 2, 1]\n *\n * console.log(array);\n * // => [3, 2, 1]\n */\n function wrapperReverse() {\n var value = this.__wrapped__;\n if (value instanceof LazyWrapper) {\n var wrapped = value;\n if (this.__actions__.length) {\n wrapped = new LazyWrapper(this);\n }\n wrapped = wrapped.reverse();\n wrapped.__actions__.push({\n 'func': thru,\n 'args': [reverse],\n 'thisArg': undefined\n });\n return new LodashWrapper(wrapped, this.__chain__);\n }\n return this.thru(reverse);\n }\n\n /**\n * Executes the chain sequence to resolve the unwrapped value.\n *\n * @name value\n * @memberOf _\n * @since 0.1.0\n * @alias toJSON, valueOf\n * @category Seq\n * @returns {*} Returns the resolved unwrapped value.\n * @example\n *\n * _([1, 2, 3]).value();\n * // => [1, 2, 3]\n */\n function wrapperValue() {\n return baseWrapperValue(this.__wrapped__, this.__actions__);\n }\n\n /*------------------------------------------------------------------------*/\n\n /**\n * Creates an object composed of keys generated from the results of running\n * each element of `collection` thru `iteratee`. The corresponding value of\n * each key is the number of times the key was returned by `iteratee`. The\n * iteratee is invoked with one argument: (value).\n *\n * @static\n * @memberOf _\n * @since 0.5.0\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} [iteratee=_.identity] The iteratee to transform keys.\n * @returns {Object} Returns the composed aggregate object.\n * @example\n *\n * _.countBy([6.1, 4.2, 6.3], Math.floor);\n * // => { '4': 1, '6': 2 }\n *\n * // The `_.property` iteratee shorthand.\n * _.countBy(['one', 'two', 'three'], 'length');\n * // => { '3': 2, '5': 1 }\n */\n var countBy = createAggregator(function(result, value, key) {\n if (hasOwnProperty.call(result, key)) {\n ++result[key];\n } else {\n baseAssignValue(result, key, 1);\n }\n });\n\n /**\n * Checks if `predicate` returns truthy for **all** elements of `collection`.\n * Iteration is stopped once `predicate` returns falsey. The predicate is\n * invoked with three arguments: (value, index|key, collection).\n *\n * **Note:** This method returns `true` for\n * [empty collections](https://en.wikipedia.org/wiki/Empty_set) because\n * [everything is true](https://en.wikipedia.org/wiki/Vacuous_truth) of\n * elements of empty collections.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} [predicate=_.identity] The function invoked per iteration.\n * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.\n * @returns {boolean} Returns `true` if all elements pass the predicate check,\n * else `false`.\n * @example\n *\n * _.every([true, 1, null, 'yes'], Boolean);\n * // => false\n *\n * var users = [\n * { 'user': 'barney', 'age': 36, 'active': false },\n * { 'user': 'fred', 'age': 40, 'active': false }\n * ];\n *\n * // The `_.matches` iteratee shorthand.\n * _.every(users, { 'user': 'barney', 'active': false });\n * // => false\n *\n * // The `_.matchesProperty` iteratee shorthand.\n * _.every(users, ['active', false]);\n * // => true\n *\n * // The `_.property` iteratee shorthand.\n * _.every(users, 'active');\n * // => false\n */\n function every(collection, predicate, guard) {\n var func = isArray(collection) ? arrayEvery : baseEvery;\n if (guard && isIterateeCall(collection, predicate, guard)) {\n predicate = undefined;\n }\n return func(collection, getIteratee(predicate, 3));\n }\n\n /**\n * Iterates over elements of `collection`, returning an array of all elements\n * `predicate` returns truthy for. The predicate is invoked with three\n * arguments: (value, index|key, collection).\n *\n * **Note:** Unlike `_.remove`, this method returns a new array.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} [predicate=_.identity] The function invoked per iteration.\n * @returns {Array} Returns the new filtered array.\n * @see _.reject\n * @example\n *\n * var users = [\n * { 'user': 'barney', 'age': 36, 'active': true },\n * { 'user': 'fred', 'age': 40, 'active': false }\n * ];\n *\n * _.filter(users, function(o) { return !o.active; });\n * // => objects for ['fred']\n *\n * // The `_.matches` iteratee shorthand.\n * _.filter(users, { 'age': 36, 'active': true });\n * // => objects for ['barney']\n *\n * // The `_.matchesProperty` iteratee shorthand.\n * _.filter(users, ['active', false]);\n * // => objects for ['fred']\n *\n * // The `_.property` iteratee shorthand.\n * _.filter(users, 'active');\n * // => objects for ['barney']\n */\n function filter(collection, predicate) {\n var func = isArray(collection) ? arrayFilter : baseFilter;\n return func(collection, getIteratee(predicate, 3));\n }\n\n /**\n * Iterates over elements of `collection`, returning the first element\n * `predicate` returns truthy for. The predicate is invoked with three\n * arguments: (value, index|key, collection).\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Collection\n * @param {Array|Object} collection The collection to inspect.\n * @param {Function} [predicate=_.identity] The function invoked per iteration.\n * @param {number} [fromIndex=0] The index to search from.\n * @returns {*} Returns the matched element, else `undefined`.\n * @example\n *\n * var users = [\n * { 'user': 'barney', 'age': 36, 'active': true },\n * { 'user': 'fred', 'age': 40, 'active': false },\n * { 'user': 'pebbles', 'age': 1, 'active': true }\n * ];\n *\n * _.find(users, function(o) { return o.age < 40; });\n * // => object for 'barney'\n *\n * // The `_.matches` iteratee shorthand.\n * _.find(users, { 'age': 1, 'active': true });\n * // => object for 'pebbles'\n *\n * // The `_.matchesProperty` iteratee shorthand.\n * _.find(users, ['active', false]);\n * // => object for 'fred'\n *\n * // The `_.property` iteratee shorthand.\n * _.find(users, 'active');\n * // => object for 'barney'\n */\n var find = createFind(findIndex);\n\n /**\n * This method is like `_.find` except that it iterates over elements of\n * `collection` from right to left.\n *\n * @static\n * @memberOf _\n * @since 2.0.0\n * @category Collection\n * @param {Array|Object} collection The collection to inspect.\n * @param {Function} [predicate=_.identity] The function invoked per iteration.\n * @param {number} [fromIndex=collection.length-1] The index to search from.\n * @returns {*} Returns the matched element, else `undefined`.\n * @example\n *\n * _.findLast([1, 2, 3, 4], function(n) {\n * return n % 2 == 1;\n * });\n * // => 3\n */\n var findLast = createFind(findLastIndex);\n\n /**\n * Creates a flattened array of values by running each element in `collection`\n * thru `iteratee` and flattening the mapped results. The iteratee is invoked\n * with three arguments: (value, index|key, collection).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} [iteratee=_.identity] The function invoked per iteration.\n * @returns {Array} Returns the new flattened array.\n * @example\n *\n * function duplicate(n) {\n * return [n, n];\n * }\n *\n * _.flatMap([1, 2], duplicate);\n * // => [1, 1, 2, 2]\n */\n function flatMap(collection, iteratee) {\n return baseFlatten(map(collection, iteratee), 1);\n }\n\n /**\n * This method is like `_.flatMap` except that it recursively flattens the\n * mapped results.\n *\n * @static\n * @memberOf _\n * @since 4.7.0\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} [iteratee=_.identity] The function invoked per iteration.\n * @returns {Array} Returns the new flattened array.\n * @example\n *\n * function duplicate(n) {\n * return [[[n, n]]];\n * }\n *\n * _.flatMapDeep([1, 2], duplicate);\n * // => [1, 1, 2, 2]\n */\n function flatMapDeep(collection, iteratee) {\n return baseFlatten(map(collection, iteratee), INFINITY);\n }\n\n /**\n * This method is like `_.flatMap` except that it recursively flattens the\n * mapped results up to `depth` times.\n *\n * @static\n * @memberOf _\n * @since 4.7.0\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} [iteratee=_.identity] The function invoked per iteration.\n * @param {number} [depth=1] The maximum recursion depth.\n * @returns {Array} Returns the new flattened array.\n * @example\n *\n * function duplicate(n) {\n * return [[[n, n]]];\n * }\n *\n * _.flatMapDepth([1, 2], duplicate, 2);\n * // => [[1, 1], [2, 2]]\n */\n function flatMapDepth(collection, iteratee, depth) {\n depth = depth === undefined ? 1 : toInteger(depth);\n return baseFlatten(map(collection, iteratee), depth);\n }\n\n /**\n * Iterates over elements of `collection` and invokes `iteratee` for each element.\n * The iteratee is invoked with three arguments: (value, index|key, collection).\n * Iteratee functions may exit iteration early by explicitly returning `false`.\n *\n * **Note:** As with other \"Collections\" methods, objects with a \"length\"\n * property are iterated like arrays. To avoid this behavior use `_.forIn`\n * or `_.forOwn` for object iteration.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @alias each\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} [iteratee=_.identity] The function invoked per iteration.\n * @returns {Array|Object} Returns `collection`.\n * @see _.forEachRight\n * @example\n *\n * _.forEach([1, 2], function(value) {\n * console.log(value);\n * });\n * // => Logs `1` then `2`.\n *\n * _.forEach({ 'a': 1, 'b': 2 }, function(value, key) {\n * console.log(key);\n * });\n * // => Logs 'a' then 'b' (iteration order is not guaranteed).\n */\n function forEach(collection, iteratee) {\n var func = isArray(collection) ? arrayEach : baseEach;\n return func(collection, getIteratee(iteratee, 3));\n }\n\n /**\n * This method is like `_.forEach` except that it iterates over elements of\n * `collection` from right to left.\n *\n * @static\n * @memberOf _\n * @since 2.0.0\n * @alias eachRight\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} [iteratee=_.identity] The function invoked per iteration.\n * @returns {Array|Object} Returns `collection`.\n * @see _.forEach\n * @example\n *\n * _.forEachRight([1, 2], function(value) {\n * console.log(value);\n * });\n * // => Logs `2` then `1`.\n */\n function forEachRight(collection, iteratee) {\n var func = isArray(collection) ? arrayEachRight : baseEachRight;\n return func(collection, getIteratee(iteratee, 3));\n }\n\n /**\n * Creates an object composed of keys generated from the results of running\n * each element of `collection` thru `iteratee`. The order of grouped values\n * is determined by the order they occur in `collection`. The corresponding\n * value of each key is an array of elements responsible for generating the\n * key. The iteratee is invoked with one argument: (value).\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} [iteratee=_.identity] The iteratee to transform keys.\n * @returns {Object} Returns the composed aggregate object.\n * @example\n *\n * _.groupBy([6.1, 4.2, 6.3], Math.floor);\n * // => { '4': [4.2], '6': [6.1, 6.3] }\n *\n * // The `_.property` iteratee shorthand.\n * _.groupBy(['one', 'two', 'three'], 'length');\n * // => { '3': ['one', 'two'], '5': ['three'] }\n */\n var groupBy = createAggregator(function(result, value, key) {\n if (hasOwnProperty.call(result, key)) {\n result[key].push(value);\n } else {\n baseAssignValue(result, key, [value]);\n }\n });\n\n /**\n * Checks if `value` is in `collection`. If `collection` is a string, it's\n * checked for a substring of `value`, otherwise\n * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)\n * is used for equality comparisons. If `fromIndex` is negative, it's used as\n * the offset from the end of `collection`.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Collection\n * @param {Array|Object|string} collection The collection to inspect.\n * @param {*} value The value to search for.\n * @param {number} [fromIndex=0] The index to search from.\n * @param- {Object} [guard] Enables use as an iteratee for methods like `_.reduce`.\n * @returns {boolean} Returns `true` if `value` is found, else `false`.\n * @example\n *\n * _.includes([1, 2, 3], 1);\n * // => true\n *\n * _.includes([1, 2, 3], 1, 2);\n * // => false\n *\n * _.includes({ 'a': 1, 'b': 2 }, 1);\n * // => true\n *\n * _.includes('abcd', 'bc');\n * // => true\n */\n function includes(collection, value, fromIndex, guard) {\n collection = isArrayLike(collection) ? collection : values(collection);\n fromIndex = (fromIndex && !guard) ? toInteger(fromIndex) : 0;\n\n var length = collection.length;\n if (fromIndex < 0) {\n fromIndex = nativeMax(length + fromIndex, 0);\n }\n return isString(collection)\n ? (fromIndex <= length && collection.indexOf(value, fromIndex) > -1)\n : (!!length && baseIndexOf(collection, value, fromIndex) > -1);\n }\n\n /**\n * Invokes the method at `path` of each element in `collection`, returning\n * an array of the results of each invoked method. Any additional arguments\n * are provided to each invoked method. If `path` is a function, it's invoked\n * for, and `this` bound to, each element in `collection`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Array|Function|string} path The path of the method to invoke or\n * the function invoked per iteration.\n * @param {...*} [args] The arguments to invoke each method with.\n * @returns {Array} Returns the array of results.\n * @example\n *\n * _.invokeMap([[5, 1, 7], [3, 2, 1]], 'sort');\n * // => [[1, 5, 7], [1, 2, 3]]\n *\n * _.invokeMap([123, 456], String.prototype.split, '');\n * // => [['1', '2', '3'], ['4', '5', '6']]\n */\n var invokeMap = baseRest(function(collection, path, args) {\n var index = -1,\n isFunc = typeof path == 'function',\n result = isArrayLike(collection) ? Array(collection.length) : [];\n\n baseEach(collection, function(value) {\n result[++index] = isFunc ? apply(path, value, args) : baseInvoke(value, path, args);\n });\n return result;\n });\n\n /**\n * Creates an object composed of keys generated from the results of running\n * each element of `collection` thru `iteratee`. The corresponding value of\n * each key is the last element responsible for generating the key. The\n * iteratee is invoked with one argument: (value).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} [iteratee=_.identity] The iteratee to transform keys.\n * @returns {Object} Returns the composed aggregate object.\n * @example\n *\n * var array = [\n * { 'dir': 'left', 'code': 97 },\n * { 'dir': 'right', 'code': 100 }\n * ];\n *\n * _.keyBy(array, function(o) {\n * return String.fromCharCode(o.code);\n * });\n * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }\n *\n * _.keyBy(array, 'dir');\n * // => { 'left': { 'dir': 'left', 'code': 97 }, 'right': { 'dir': 'right', 'code': 100 } }\n */\n var keyBy = createAggregator(function(result, value, key) {\n baseAssignValue(result, key, value);\n });\n\n /**\n * Creates an array of values by running each element in `collection` thru\n * `iteratee`. The iteratee is invoked with three arguments:\n * (value, index|key, collection).\n *\n * Many lodash methods are guarded to work as iteratees for methods like\n * `_.every`, `_.filter`, `_.map`, `_.mapValues`, `_.reject`, and `_.some`.\n *\n * The guarded methods are:\n * `ary`, `chunk`, `curry`, `curryRight`, `drop`, `dropRight`, `every`,\n * `fill`, `invert`, `parseInt`, `random`, `range`, `rangeRight`, `repeat`,\n * `sampleSize`, `slice`, `some`, `sortBy`, `split`, `take`, `takeRight`,\n * `template`, `trim`, `trimEnd`, `trimStart`, and `words`\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} [iteratee=_.identity] The function invoked per iteration.\n * @returns {Array} Returns the new mapped array.\n * @example\n *\n * function square(n) {\n * return n * n;\n * }\n *\n * _.map([4, 8], square);\n * // => [16, 64]\n *\n * _.map({ 'a': 4, 'b': 8 }, square);\n * // => [16, 64] (iteration order is not guaranteed)\n *\n * var users = [\n * { 'user': 'barney' },\n * { 'user': 'fred' }\n * ];\n *\n * // The `_.property` iteratee shorthand.\n * _.map(users, 'user');\n * // => ['barney', 'fred']\n */\n function map(collection, iteratee) {\n var func = isArray(collection) ? arrayMap : baseMap;\n return func(collection, getIteratee(iteratee, 3));\n }\n\n /**\n * This method is like `_.sortBy` except that it allows specifying the sort\n * orders of the iteratees to sort by. If `orders` is unspecified, all values\n * are sorted in ascending order. Otherwise, specify an order of \"desc\" for\n * descending or \"asc\" for ascending sort order of corresponding values.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Array[]|Function[]|Object[]|string[]} [iteratees=[_.identity]]\n * The iteratees to sort by.\n * @param {string[]} [orders] The sort orders of `iteratees`.\n * @param- {Object} [guard] Enables use as an iteratee for methods like `_.reduce`.\n * @returns {Array} Returns the new sorted array.\n * @example\n *\n * var users = [\n * { 'user': 'fred', 'age': 48 },\n * { 'user': 'barney', 'age': 34 },\n * { 'user': 'fred', 'age': 40 },\n * { 'user': 'barney', 'age': 36 }\n * ];\n *\n * // Sort by `user` in ascending order and by `age` in descending order.\n * _.orderBy(users, ['user', 'age'], ['asc', 'desc']);\n * // => objects for [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 40]]\n */\n function orderBy(collection, iteratees, orders, guard) {\n if (collection == null) {\n return [];\n }\n if (!isArray(iteratees)) {\n iteratees = iteratees == null ? [] : [iteratees];\n }\n orders = guard ? undefined : orders;\n if (!isArray(orders)) {\n orders = orders == null ? [] : [orders];\n }\n return baseOrderBy(collection, iteratees, orders);\n }\n\n /**\n * Creates an array of elements split into two groups, the first of which\n * contains elements `predicate` returns truthy for, the second of which\n * contains elements `predicate` returns falsey for. The predicate is\n * invoked with one argument: (value).\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} [predicate=_.identity] The function invoked per iteration.\n * @returns {Array} Returns the array of grouped elements.\n * @example\n *\n * var users = [\n * { 'user': 'barney', 'age': 36, 'active': false },\n * { 'user': 'fred', 'age': 40, 'active': true },\n * { 'user': 'pebbles', 'age': 1, 'active': false }\n * ];\n *\n * _.partition(users, function(o) { return o.active; });\n * // => objects for [['fred'], ['barney', 'pebbles']]\n *\n * // The `_.matches` iteratee shorthand.\n * _.partition(users, { 'age': 1, 'active': false });\n * // => objects for [['pebbles'], ['barney', 'fred']]\n *\n * // The `_.matchesProperty` iteratee shorthand.\n * _.partition(users, ['active', false]);\n * // => objects for [['barney', 'pebbles'], ['fred']]\n *\n * // The `_.property` iteratee shorthand.\n * _.partition(users, 'active');\n * // => objects for [['fred'], ['barney', 'pebbles']]\n */\n var partition = createAggregator(function(result, value, key) {\n result[key ? 0 : 1].push(value);\n }, function() { return [[], []]; });\n\n /**\n * Reduces `collection` to a value which is the accumulated result of running\n * each element in `collection` thru `iteratee`, where each successive\n * invocation is supplied the return value of the previous. If `accumulator`\n * is not given, the first element of `collection` is used as the initial\n * value. The iteratee is invoked with four arguments:\n * (accumulator, value, index|key, collection).\n *\n * Many lodash methods are guarded to work as iteratees for methods like\n * `_.reduce`, `_.reduceRight`, and `_.transform`.\n *\n * The guarded methods are:\n * `assign`, `defaults`, `defaultsDeep`, `includes`, `merge`, `orderBy`,\n * and `sortBy`\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} [iteratee=_.identity] The function invoked per iteration.\n * @param {*} [accumulator] The initial value.\n * @returns {*} Returns the accumulated value.\n * @see _.reduceRight\n * @example\n *\n * _.reduce([1, 2], function(sum, n) {\n * return sum + n;\n * }, 0);\n * // => 3\n *\n * _.reduce({ 'a': 1, 'b': 2, 'c': 1 }, function(result, value, key) {\n * (result[value] || (result[value] = [])).push(key);\n * return result;\n * }, {});\n * // => { '1': ['a', 'c'], '2': ['b'] } (iteration order is not guaranteed)\n */\n function reduce(collection, iteratee, accumulator) {\n var func = isArray(collection) ? arrayReduce : baseReduce,\n initAccum = arguments.length < 3;\n\n return func(collection, getIteratee(iteratee, 4), accumulator, initAccum, baseEach);\n }\n\n /**\n * This method is like `_.reduce` except that it iterates over elements of\n * `collection` from right to left.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} [iteratee=_.identity] The function invoked per iteration.\n * @param {*} [accumulator] The initial value.\n * @returns {*} Returns the accumulated value.\n * @see _.reduce\n * @example\n *\n * var array = [[0, 1], [2, 3], [4, 5]];\n *\n * _.reduceRight(array, function(flattened, other) {\n * return flattened.concat(other);\n * }, []);\n * // => [4, 5, 2, 3, 0, 1]\n */\n function reduceRight(collection, iteratee, accumulator) {\n var func = isArray(collection) ? arrayReduceRight : baseReduce,\n initAccum = arguments.length < 3;\n\n return func(collection, getIteratee(iteratee, 4), accumulator, initAccum, baseEachRight);\n }\n\n /**\n * The opposite of `_.filter`; this method returns the elements of `collection`\n * that `predicate` does **not** return truthy for.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} [predicate=_.identity] The function invoked per iteration.\n * @returns {Array} Returns the new filtered array.\n * @see _.filter\n * @example\n *\n * var users = [\n * { 'user': 'barney', 'age': 36, 'active': false },\n * { 'user': 'fred', 'age': 40, 'active': true }\n * ];\n *\n * _.reject(users, function(o) { return !o.active; });\n * // => objects for ['fred']\n *\n * // The `_.matches` iteratee shorthand.\n * _.reject(users, { 'age': 40, 'active': true });\n * // => objects for ['barney']\n *\n * // The `_.matchesProperty` iteratee shorthand.\n * _.reject(users, ['active', false]);\n * // => objects for ['fred']\n *\n * // The `_.property` iteratee shorthand.\n * _.reject(users, 'active');\n * // => objects for ['barney']\n */\n function reject(collection, predicate) {\n var func = isArray(collection) ? arrayFilter : baseFilter;\n return func(collection, negate(getIteratee(predicate, 3)));\n }\n\n /**\n * Gets a random element from `collection`.\n *\n * @static\n * @memberOf _\n * @since 2.0.0\n * @category Collection\n * @param {Array|Object} collection The collection to sample.\n * @returns {*} Returns the random element.\n * @example\n *\n * _.sample([1, 2, 3, 4]);\n * // => 2\n */\n function sample(collection) {\n var func = isArray(collection) ? arraySample : baseSample;\n return func(collection);\n }\n\n /**\n * Gets `n` random elements at unique keys from `collection` up to the\n * size of `collection`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Collection\n * @param {Array|Object} collection The collection to sample.\n * @param {number} [n=1] The number of elements to sample.\n * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.\n * @returns {Array} Returns the random elements.\n * @example\n *\n * _.sampleSize([1, 2, 3], 2);\n * // => [3, 1]\n *\n * _.sampleSize([1, 2, 3], 4);\n * // => [2, 3, 1]\n */\n function sampleSize(collection, n, guard) {\n if ((guard ? isIterateeCall(collection, n, guard) : n === undefined)) {\n n = 1;\n } else {\n n = toInteger(n);\n }\n var func = isArray(collection) ? arraySampleSize : baseSampleSize;\n return func(collection, n);\n }\n\n /**\n * Creates an array of shuffled values, using a version of the\n * [Fisher-Yates shuffle](https://en.wikipedia.org/wiki/Fisher-Yates_shuffle).\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Collection\n * @param {Array|Object} collection The collection to shuffle.\n * @returns {Array} Returns the new shuffled array.\n * @example\n *\n * _.shuffle([1, 2, 3, 4]);\n * // => [4, 1, 3, 2]\n */\n function shuffle(collection) {\n var func = isArray(collection) ? arrayShuffle : baseShuffle;\n return func(collection);\n }\n\n /**\n * Gets the size of `collection` by returning its length for array-like\n * values or the number of own enumerable string keyed properties for objects.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Collection\n * @param {Array|Object|string} collection The collection to inspect.\n * @returns {number} Returns the collection size.\n * @example\n *\n * _.size([1, 2, 3]);\n * // => 3\n *\n * _.size({ 'a': 1, 'b': 2 });\n * // => 2\n *\n * _.size('pebbles');\n * // => 7\n */\n function size(collection) {\n if (collection == null) {\n return 0;\n }\n if (isArrayLike(collection)) {\n return isString(collection) ? stringSize(collection) : collection.length;\n }\n var tag = getTag(collection);\n if (tag == mapTag || tag == setTag) {\n return collection.size;\n }\n return baseKeys(collection).length;\n }\n\n /**\n * Checks if `predicate` returns truthy for **any** element of `collection`.\n * Iteration is stopped once `predicate` returns truthy. The predicate is\n * invoked with three arguments: (value, index|key, collection).\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {Function} [predicate=_.identity] The function invoked per iteration.\n * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.\n * @returns {boolean} Returns `true` if any element passes the predicate check,\n * else `false`.\n * @example\n *\n * _.some([null, 0, 'yes', false], Boolean);\n * // => true\n *\n * var users = [\n * { 'user': 'barney', 'active': true },\n * { 'user': 'fred', 'active': false }\n * ];\n *\n * // The `_.matches` iteratee shorthand.\n * _.some(users, { 'user': 'barney', 'active': false });\n * // => false\n *\n * // The `_.matchesProperty` iteratee shorthand.\n * _.some(users, ['active', false]);\n * // => true\n *\n * // The `_.property` iteratee shorthand.\n * _.some(users, 'active');\n * // => true\n */\n function some(collection, predicate, guard) {\n var func = isArray(collection) ? arraySome : baseSome;\n if (guard && isIterateeCall(collection, predicate, guard)) {\n predicate = undefined;\n }\n return func(collection, getIteratee(predicate, 3));\n }\n\n /**\n * Creates an array of elements, sorted in ascending order by the results of\n * running each element in a collection thru each iteratee. This method\n * performs a stable sort, that is, it preserves the original sort order of\n * equal elements. The iteratees are invoked with one argument: (value).\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Collection\n * @param {Array|Object} collection The collection to iterate over.\n * @param {...(Function|Function[])} [iteratees=[_.identity]]\n * The iteratees to sort by.\n * @returns {Array} Returns the new sorted array.\n * @example\n *\n * var users = [\n * { 'user': 'fred', 'age': 48 },\n * { 'user': 'barney', 'age': 36 },\n * { 'user': 'fred', 'age': 40 },\n * { 'user': 'barney', 'age': 34 }\n * ];\n *\n * _.sortBy(users, [function(o) { return o.user; }]);\n * // => objects for [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 40]]\n *\n * _.sortBy(users, ['user', 'age']);\n * // => objects for [['barney', 34], ['barney', 36], ['fred', 40], ['fred', 48]]\n */\n var sortBy = baseRest(function(collection, iteratees) {\n if (collection == null) {\n return [];\n }\n var length = iteratees.length;\n if (length > 1 && isIterateeCall(collection, iteratees[0], iteratees[1])) {\n iteratees = [];\n } else if (length > 2 && isIterateeCall(iteratees[0], iteratees[1], iteratees[2])) {\n iteratees = [iteratees[0]];\n }\n return baseOrderBy(collection, baseFlatten(iteratees, 1), []);\n });\n\n /*------------------------------------------------------------------------*/\n\n /**\n * Gets the timestamp of the number of milliseconds that have elapsed since\n * the Unix epoch (1 January 1970 00:00:00 UTC).\n *\n * @static\n * @memberOf _\n * @since 2.4.0\n * @category Date\n * @returns {number} Returns the timestamp.\n * @example\n *\n * _.defer(function(stamp) {\n * console.log(_.now() - stamp);\n * }, _.now());\n * // => Logs the number of milliseconds it took for the deferred invocation.\n */\n var now = ctxNow || function() {\n return root.Date.now();\n };\n\n /*------------------------------------------------------------------------*/\n\n /**\n * The opposite of `_.before`; this method creates a function that invokes\n * `func` once it's called `n` or more times.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Function\n * @param {number} n The number of calls before `func` is invoked.\n * @param {Function} func The function to restrict.\n * @returns {Function} Returns the new restricted function.\n * @example\n *\n * var saves = ['profile', 'settings'];\n *\n * var done = _.after(saves.length, function() {\n * console.log('done saving!');\n * });\n *\n * _.forEach(saves, function(type) {\n * asyncSave({ 'type': type, 'complete': done });\n * });\n * // => Logs 'done saving!' after the two async saves have completed.\n */\n function after(n, func) {\n if (typeof func != 'function') {\n throw new TypeError(FUNC_ERROR_TEXT);\n }\n n = toInteger(n);\n return function() {\n if (--n < 1) {\n return func.apply(this, arguments);\n }\n };\n }\n\n /**\n * Creates a function that invokes `func`, with up to `n` arguments,\n * ignoring any additional arguments.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Function\n * @param {Function} func The function to cap arguments for.\n * @param {number} [n=func.length] The arity cap.\n * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.\n * @returns {Function} Returns the new capped function.\n * @example\n *\n * _.map(['6', '8', '10'], _.ary(parseInt, 1));\n * // => [6, 8, 10]\n */\n function ary(func, n, guard) {\n n = guard ? undefined : n;\n n = (func && n == null) ? func.length : n;\n return createWrap(func, WRAP_ARY_FLAG, undefined, undefined, undefined, undefined, n);\n }\n\n /**\n * Creates a function that invokes `func`, with the `this` binding and arguments\n * of the created function, while it's called less than `n` times. Subsequent\n * calls to the created function return the result of the last `func` invocation.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Function\n * @param {number} n The number of calls at which `func` is no longer invoked.\n * @param {Function} func The function to restrict.\n * @returns {Function} Returns the new restricted function.\n * @example\n *\n * jQuery(element).on('click', _.before(5, addContactToList));\n * // => Allows adding up to 4 contacts to the list.\n */\n function before(n, func) {\n var result;\n if (typeof func != 'function') {\n throw new TypeError(FUNC_ERROR_TEXT);\n }\n n = toInteger(n);\n return function() {\n if (--n > 0) {\n result = func.apply(this, arguments);\n }\n if (n <= 1) {\n func = undefined;\n }\n return result;\n };\n }\n\n /**\n * Creates a function that invokes `func` with the `this` binding of `thisArg`\n * and `partials` prepended to the arguments it receives.\n *\n * The `_.bind.placeholder` value, which defaults to `_` in monolithic builds,\n * may be used as a placeholder for partially applied arguments.\n *\n * **Note:** Unlike native `Function#bind`, this method doesn't set the \"length\"\n * property of bound functions.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Function\n * @param {Function} func The function to bind.\n * @param {*} thisArg The `this` binding of `func`.\n * @param {...*} [partials] The arguments to be partially applied.\n * @returns {Function} Returns the new bound function.\n * @example\n *\n * function greet(greeting, punctuation) {\n * return greeting + ' ' + this.user + punctuation;\n * }\n *\n * var object = { 'user': 'fred' };\n *\n * var bound = _.bind(greet, object, 'hi');\n * bound('!');\n * // => 'hi fred!'\n *\n * // Bound with placeholders.\n * var bound = _.bind(greet, object, _, '!');\n * bound('hi');\n * // => 'hi fred!'\n */\n var bind = baseRest(function(func, thisArg, partials) {\n var bitmask = WRAP_BIND_FLAG;\n if (partials.length) {\n var holders = replaceHolders(partials, getHolder(bind));\n bitmask |= WRAP_PARTIAL_FLAG;\n }\n return createWrap(func, bitmask, thisArg, partials, holders);\n });\n\n /**\n * Creates a function that invokes the method at `object[key]` with `partials`\n * prepended to the arguments it receives.\n *\n * This method differs from `_.bind` by allowing bound functions to reference\n * methods that may be redefined or don't yet exist. See\n * [Peter Michaux's article](http://peter.michaux.ca/articles/lazy-function-definition-pattern)\n * for more details.\n *\n * The `_.bindKey.placeholder` value, which defaults to `_` in monolithic\n * builds, may be used as a placeholder for partially applied arguments.\n *\n * @static\n * @memberOf _\n * @since 0.10.0\n * @category Function\n * @param {Object} object The object to invoke the method on.\n * @param {string} key The key of the method.\n * @param {...*} [partials] The arguments to be partially applied.\n * @returns {Function} Returns the new bound function.\n * @example\n *\n * var object = {\n * 'user': 'fred',\n * 'greet': function(greeting, punctuation) {\n * return greeting + ' ' + this.user + punctuation;\n * }\n * };\n *\n * var bound = _.bindKey(object, 'greet', 'hi');\n * bound('!');\n * // => 'hi fred!'\n *\n * object.greet = function(greeting, punctuation) {\n * return greeting + 'ya ' + this.user + punctuation;\n * };\n *\n * bound('!');\n * // => 'hiya fred!'\n *\n * // Bound with placeholders.\n * var bound = _.bindKey(object, 'greet', _, '!');\n * bound('hi');\n * // => 'hiya fred!'\n */\n var bindKey = baseRest(function(object, key, partials) {\n var bitmask = WRAP_BIND_FLAG | WRAP_BIND_KEY_FLAG;\n if (partials.length) {\n var holders = replaceHolders(partials, getHolder(bindKey));\n bitmask |= WRAP_PARTIAL_FLAG;\n }\n return createWrap(key, bitmask, object, partials, holders);\n });\n\n /**\n * Creates a function that accepts arguments of `func` and either invokes\n * `func` returning its result, if at least `arity` number of arguments have\n * been provided, or returns a function that accepts the remaining `func`\n * arguments, and so on. The arity of `func` may be specified if `func.length`\n * is not sufficient.\n *\n * The `_.curry.placeholder` value, which defaults to `_` in monolithic builds,\n * may be used as a placeholder for provided arguments.\n *\n * **Note:** This method doesn't set the \"length\" property of curried functions.\n *\n * @static\n * @memberOf _\n * @since 2.0.0\n * @category Function\n * @param {Function} func The function to curry.\n * @param {number} [arity=func.length] The arity of `func`.\n * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.\n * @returns {Function} Returns the new curried function.\n * @example\n *\n * var abc = function(a, b, c) {\n * return [a, b, c];\n * };\n *\n * var curried = _.curry(abc);\n *\n * curried(1)(2)(3);\n * // => [1, 2, 3]\n *\n * curried(1, 2)(3);\n * // => [1, 2, 3]\n *\n * curried(1, 2, 3);\n * // => [1, 2, 3]\n *\n * // Curried with placeholders.\n * curried(1)(_, 3)(2);\n * // => [1, 2, 3]\n */\n function curry(func, arity, guard) {\n arity = guard ? undefined : arity;\n var result = createWrap(func, WRAP_CURRY_FLAG, undefined, undefined, undefined, undefined, undefined, arity);\n result.placeholder = curry.placeholder;\n return result;\n }\n\n /**\n * This method is like `_.curry` except that arguments are applied to `func`\n * in the manner of `_.partialRight` instead of `_.partial`.\n *\n * The `_.curryRight.placeholder` value, which defaults to `_` in monolithic\n * builds, may be used as a placeholder for provided arguments.\n *\n * **Note:** This method doesn't set the \"length\" property of curried functions.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Function\n * @param {Function} func The function to curry.\n * @param {number} [arity=func.length] The arity of `func`.\n * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.\n * @returns {Function} Returns the new curried function.\n * @example\n *\n * var abc = function(a, b, c) {\n * return [a, b, c];\n * };\n *\n * var curried = _.curryRight(abc);\n *\n * curried(3)(2)(1);\n * // => [1, 2, 3]\n *\n * curried(2, 3)(1);\n * // => [1, 2, 3]\n *\n * curried(1, 2, 3);\n * // => [1, 2, 3]\n *\n * // Curried with placeholders.\n * curried(3)(1, _)(2);\n * // => [1, 2, 3]\n */\n function curryRight(func, arity, guard) {\n arity = guard ? undefined : arity;\n var result = createWrap(func, WRAP_CURRY_RIGHT_FLAG, undefined, undefined, undefined, undefined, undefined, arity);\n result.placeholder = curryRight.placeholder;\n return result;\n }\n\n /**\n * Creates a debounced function that delays invoking `func` until after `wait`\n * milliseconds have elapsed since the last time the debounced function was\n * invoked. The debounced function comes with a `cancel` method to cancel\n * delayed `func` invocations and a `flush` method to immediately invoke them.\n * Provide `options` to indicate whether `func` should be invoked on the\n * leading and/or trailing edge of the `wait` timeout. The `func` is invoked\n * with the last arguments provided to the debounced function. Subsequent\n * calls to the debounced function return the result of the last `func`\n * invocation.\n *\n * **Note:** If `leading` and `trailing` options are `true`, `func` is\n * invoked on the trailing edge of the timeout only if the debounced function\n * is invoked more than once during the `wait` timeout.\n *\n * If `wait` is `0` and `leading` is `false`, `func` invocation is deferred\n * until to the next tick, similar to `setTimeout` with a timeout of `0`.\n *\n * See [David Corbacho's article](https://css-tricks.com/debouncing-throttling-explained-examples/)\n * for details over the differences between `_.debounce` and `_.throttle`.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Function\n * @param {Function} func The function to debounce.\n * @param {number} [wait=0] The number of milliseconds to delay.\n * @param {Object} [options={}] The options object.\n * @param {boolean} [options.leading=false]\n * Specify invoking on the leading edge of the timeout.\n * @param {number} [options.maxWait]\n * The maximum time `func` is allowed to be delayed before it's invoked.\n * @param {boolean} [options.trailing=true]\n * Specify invoking on the trailing edge of the timeout.\n * @returns {Function} Returns the new debounced function.\n * @example\n *\n * // Avoid costly calculations while the window size is in flux.\n * jQuery(window).on('resize', _.debounce(calculateLayout, 150));\n *\n * // Invoke `sendMail` when clicked, debouncing subsequent calls.\n * jQuery(element).on('click', _.debounce(sendMail, 300, {\n * 'leading': true,\n * 'trailing': false\n * }));\n *\n * // Ensure `batchLog` is invoked once after 1 second of debounced calls.\n * var debounced = _.debounce(batchLog, 250, { 'maxWait': 1000 });\n * var source = new EventSource('/stream');\n * jQuery(source).on('message', debounced);\n *\n * // Cancel the trailing debounced invocation.\n * jQuery(window).on('popstate', debounced.cancel);\n */\n function debounce(func, wait, options) {\n var lastArgs,\n lastThis,\n maxWait,\n result,\n timerId,\n lastCallTime,\n lastInvokeTime = 0,\n leading = false,\n maxing = false,\n trailing = true;\n\n if (typeof func != 'function') {\n throw new TypeError(FUNC_ERROR_TEXT);\n }\n wait = toNumber(wait) || 0;\n if (isObject(options)) {\n leading = !!options.leading;\n maxing = 'maxWait' in options;\n maxWait = maxing ? nativeMax(toNumber(options.maxWait) || 0, wait) : maxWait;\n trailing = 'trailing' in options ? !!options.trailing : trailing;\n }\n\n function invokeFunc(time) {\n var args = lastArgs,\n thisArg = lastThis;\n\n lastArgs = lastThis = undefined;\n lastInvokeTime = time;\n result = func.apply(thisArg, args);\n return result;\n }\n\n function leadingEdge(time) {\n // Reset any `maxWait` timer.\n lastInvokeTime = time;\n // Start the timer for the trailing edge.\n timerId = setTimeout(timerExpired, wait);\n // Invoke the leading edge.\n return leading ? invokeFunc(time) : result;\n }\n\n function remainingWait(time) {\n var timeSinceLastCall = time - lastCallTime,\n timeSinceLastInvoke = time - lastInvokeTime,\n timeWaiting = wait - timeSinceLastCall;\n\n return maxing\n ? nativeMin(timeWaiting, maxWait - timeSinceLastInvoke)\n : timeWaiting;\n }\n\n function shouldInvoke(time) {\n var timeSinceLastCall = time - lastCallTime,\n timeSinceLastInvoke = time - lastInvokeTime;\n\n // Either this is the first call, activity has stopped and we're at the\n // trailing edge, the system time has gone backwards and we're treating\n // it as the trailing edge, or we've hit the `maxWait` limit.\n return (lastCallTime === undefined || (timeSinceLastCall >= wait) ||\n (timeSinceLastCall < 0) || (maxing && timeSinceLastInvoke >= maxWait));\n }\n\n function timerExpired() {\n var time = now();\n if (shouldInvoke(time)) {\n return trailingEdge(time);\n }\n // Restart the timer.\n timerId = setTimeout(timerExpired, remainingWait(time));\n }\n\n function trailingEdge(time) {\n timerId = undefined;\n\n // Only invoke if we have `lastArgs` which means `func` has been\n // debounced at least once.\n if (trailing && lastArgs) {\n return invokeFunc(time);\n }\n lastArgs = lastThis = undefined;\n return result;\n }\n\n function cancel() {\n if (timerId !== undefined) {\n clearTimeout(timerId);\n }\n lastInvokeTime = 0;\n lastArgs = lastCallTime = lastThis = timerId = undefined;\n }\n\n function flush() {\n return timerId === undefined ? result : trailingEdge(now());\n }\n\n function debounced() {\n var time = now(),\n isInvoking = shouldInvoke(time);\n\n lastArgs = arguments;\n lastThis = this;\n lastCallTime = time;\n\n if (isInvoking) {\n if (timerId === undefined) {\n return leadingEdge(lastCallTime);\n }\n if (maxing) {\n // Handle invocations in a tight loop.\n clearTimeout(timerId);\n timerId = setTimeout(timerExpired, wait);\n return invokeFunc(lastCallTime);\n }\n }\n if (timerId === undefined) {\n timerId = setTimeout(timerExpired, wait);\n }\n return result;\n }\n debounced.cancel = cancel;\n debounced.flush = flush;\n return debounced;\n }\n\n /**\n * Defers invoking the `func` until the current call stack has cleared. Any\n * additional arguments are provided to `func` when it's invoked.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Function\n * @param {Function} func The function to defer.\n * @param {...*} [args] The arguments to invoke `func` with.\n * @returns {number} Returns the timer id.\n * @example\n *\n * _.defer(function(text) {\n * console.log(text);\n * }, 'deferred');\n * // => Logs 'deferred' after one millisecond.\n */\n var defer = baseRest(function(func, args) {\n return baseDelay(func, 1, args);\n });\n\n /**\n * Invokes `func` after `wait` milliseconds. Any additional arguments are\n * provided to `func` when it's invoked.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Function\n * @param {Function} func The function to delay.\n * @param {number} wait The number of milliseconds to delay invocation.\n * @param {...*} [args] The arguments to invoke `func` with.\n * @returns {number} Returns the timer id.\n * @example\n *\n * _.delay(function(text) {\n * console.log(text);\n * }, 1000, 'later');\n * // => Logs 'later' after one second.\n */\n var delay = baseRest(function(func, wait, args) {\n return baseDelay(func, toNumber(wait) || 0, args);\n });\n\n /**\n * Creates a function that invokes `func` with arguments reversed.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Function\n * @param {Function} func The function to flip arguments for.\n * @returns {Function} Returns the new flipped function.\n * @example\n *\n * var flipped = _.flip(function() {\n * return _.toArray(arguments);\n * });\n *\n * flipped('a', 'b', 'c', 'd');\n * // => ['d', 'c', 'b', 'a']\n */\n function flip(func) {\n return createWrap(func, WRAP_FLIP_FLAG);\n }\n\n /**\n * Creates a function that memoizes the result of `func`. If `resolver` is\n * provided, it determines the cache key for storing the result based on the\n * arguments provided to the memoized function. By default, the first argument\n * provided to the memoized function is used as the map cache key. The `func`\n * is invoked with the `this` binding of the memoized function.\n *\n * **Note:** The cache is exposed as the `cache` property on the memoized\n * function. Its creation may be customized by replacing the `_.memoize.Cache`\n * constructor with one whose instances implement the\n * [`Map`](http://ecma-international.org/ecma-262/7.0/#sec-properties-of-the-map-prototype-object)\n * method interface of `clear`, `delete`, `get`, `has`, and `set`.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Function\n * @param {Function} func The function to have its output memoized.\n * @param {Function} [resolver] The function to resolve the cache key.\n * @returns {Function} Returns the new memoized function.\n * @example\n *\n * var object = { 'a': 1, 'b': 2 };\n * var other = { 'c': 3, 'd': 4 };\n *\n * var values = _.memoize(_.values);\n * values(object);\n * // => [1, 2]\n *\n * values(other);\n * // => [3, 4]\n *\n * object.a = 2;\n * values(object);\n * // => [1, 2]\n *\n * // Modify the result cache.\n * values.cache.set(object, ['a', 'b']);\n * values(object);\n * // => ['a', 'b']\n *\n * // Replace `_.memoize.Cache`.\n * _.memoize.Cache = WeakMap;\n */\n function memoize(func, resolver) {\n if (typeof func != 'function' || (resolver != null && typeof resolver != 'function')) {\n throw new TypeError(FUNC_ERROR_TEXT);\n }\n var memoized = function() {\n var args = arguments,\n key = resolver ? resolver.apply(this, args) : args[0],\n cache = memoized.cache;\n\n if (cache.has(key)) {\n return cache.get(key);\n }\n var result = func.apply(this, args);\n memoized.cache = cache.set(key, result) || cache;\n return result;\n };\n memoized.cache = new (memoize.Cache || MapCache);\n return memoized;\n }\n\n // Expose `MapCache`.\n memoize.Cache = MapCache;\n\n /**\n * Creates a function that negates the result of the predicate `func`. The\n * `func` predicate is invoked with the `this` binding and arguments of the\n * created function.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Function\n * @param {Function} predicate The predicate to negate.\n * @returns {Function} Returns the new negated function.\n * @example\n *\n * function isEven(n) {\n * return n % 2 == 0;\n * }\n *\n * _.filter([1, 2, 3, 4, 5, 6], _.negate(isEven));\n * // => [1, 3, 5]\n */\n function negate(predicate) {\n if (typeof predicate != 'function') {\n throw new TypeError(FUNC_ERROR_TEXT);\n }\n return function() {\n var args = arguments;\n switch (args.length) {\n case 0: return !predicate.call(this);\n case 1: return !predicate.call(this, args[0]);\n case 2: return !predicate.call(this, args[0], args[1]);\n case 3: return !predicate.call(this, args[0], args[1], args[2]);\n }\n return !predicate.apply(this, args);\n };\n }\n\n /**\n * Creates a function that is restricted to invoking `func` once. Repeat calls\n * to the function return the value of the first invocation. The `func` is\n * invoked with the `this` binding and arguments of the created function.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Function\n * @param {Function} func The function to restrict.\n * @returns {Function} Returns the new restricted function.\n * @example\n *\n * var initialize = _.once(createApplication);\n * initialize();\n * initialize();\n * // => `createApplication` is invoked once\n */\n function once(func) {\n return before(2, func);\n }\n\n /**\n * Creates a function that invokes `func` with its arguments transformed.\n *\n * @static\n * @since 4.0.0\n * @memberOf _\n * @category Function\n * @param {Function} func The function to wrap.\n * @param {...(Function|Function[])} [transforms=[_.identity]]\n * The argument transforms.\n * @returns {Function} Returns the new function.\n * @example\n *\n * function doubled(n) {\n * return n * 2;\n * }\n *\n * function square(n) {\n * return n * n;\n * }\n *\n * var func = _.overArgs(function(x, y) {\n * return [x, y];\n * }, [square, doubled]);\n *\n * func(9, 3);\n * // => [81, 6]\n *\n * func(10, 5);\n * // => [100, 10]\n */\n var overArgs = castRest(function(func, transforms) {\n transforms = (transforms.length == 1 && isArray(transforms[0]))\n ? arrayMap(transforms[0], baseUnary(getIteratee()))\n : arrayMap(baseFlatten(transforms, 1), baseUnary(getIteratee()));\n\n var funcsLength = transforms.length;\n return baseRest(function(args) {\n var index = -1,\n length = nativeMin(args.length, funcsLength);\n\n while (++index < length) {\n args[index] = transforms[index].call(this, args[index]);\n }\n return apply(func, this, args);\n });\n });\n\n /**\n * Creates a function that invokes `func` with `partials` prepended to the\n * arguments it receives. This method is like `_.bind` except it does **not**\n * alter the `this` binding.\n *\n * The `_.partial.placeholder` value, which defaults to `_` in monolithic\n * builds, may be used as a placeholder for partially applied arguments.\n *\n * **Note:** This method doesn't set the \"length\" property of partially\n * applied functions.\n *\n * @static\n * @memberOf _\n * @since 0.2.0\n * @category Function\n * @param {Function} func The function to partially apply arguments to.\n * @param {...*} [partials] The arguments to be partially applied.\n * @returns {Function} Returns the new partially applied function.\n * @example\n *\n * function greet(greeting, name) {\n * return greeting + ' ' + name;\n * }\n *\n * var sayHelloTo = _.partial(greet, 'hello');\n * sayHelloTo('fred');\n * // => 'hello fred'\n *\n * // Partially applied with placeholders.\n * var greetFred = _.partial(greet, _, 'fred');\n * greetFred('hi');\n * // => 'hi fred'\n */\n var partial = baseRest(function(func, partials) {\n var holders = replaceHolders(partials, getHolder(partial));\n return createWrap(func, WRAP_PARTIAL_FLAG, undefined, partials, holders);\n });\n\n /**\n * This method is like `_.partial` except that partially applied arguments\n * are appended to the arguments it receives.\n *\n * The `_.partialRight.placeholder` value, which defaults to `_` in monolithic\n * builds, may be used as a placeholder for partially applied arguments.\n *\n * **Note:** This method doesn't set the \"length\" property of partially\n * applied functions.\n *\n * @static\n * @memberOf _\n * @since 1.0.0\n * @category Function\n * @param {Function} func The function to partially apply arguments to.\n * @param {...*} [partials] The arguments to be partially applied.\n * @returns {Function} Returns the new partially applied function.\n * @example\n *\n * function greet(greeting, name) {\n * return greeting + ' ' + name;\n * }\n *\n * var greetFred = _.partialRight(greet, 'fred');\n * greetFred('hi');\n * // => 'hi fred'\n *\n * // Partially applied with placeholders.\n * var sayHelloTo = _.partialRight(greet, 'hello', _);\n * sayHelloTo('fred');\n * // => 'hello fred'\n */\n var partialRight = baseRest(function(func, partials) {\n var holders = replaceHolders(partials, getHolder(partialRight));\n return createWrap(func, WRAP_PARTIAL_RIGHT_FLAG, undefined, partials, holders);\n });\n\n /**\n * Creates a function that invokes `func` with arguments arranged according\n * to the specified `indexes` where the argument value at the first index is\n * provided as the first argument, the argument value at the second index is\n * provided as the second argument, and so on.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Function\n * @param {Function} func The function to rearrange arguments for.\n * @param {...(number|number[])} indexes The arranged argument indexes.\n * @returns {Function} Returns the new function.\n * @example\n *\n * var rearged = _.rearg(function(a, b, c) {\n * return [a, b, c];\n * }, [2, 0, 1]);\n *\n * rearged('b', 'c', 'a')\n * // => ['a', 'b', 'c']\n */\n var rearg = flatRest(function(func, indexes) {\n return createWrap(func, WRAP_REARG_FLAG, undefined, undefined, undefined, indexes);\n });\n\n /**\n * Creates a function that invokes `func` with the `this` binding of the\n * created function and arguments from `start` and beyond provided as\n * an array.\n *\n * **Note:** This method is based on the\n * [rest parameter](https://mdn.io/rest_parameters).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Function\n * @param {Function} func The function to apply a rest parameter to.\n * @param {number} [start=func.length-1] The start position of the rest parameter.\n * @returns {Function} Returns the new function.\n * @example\n *\n * var say = _.rest(function(what, names) {\n * return what + ' ' + _.initial(names).join(', ') +\n * (_.size(names) > 1 ? ', & ' : '') + _.last(names);\n * });\n *\n * say('hello', 'fred', 'barney', 'pebbles');\n * // => 'hello fred, barney, & pebbles'\n */\n function rest(func, start) {\n if (typeof func != 'function') {\n throw new TypeError(FUNC_ERROR_TEXT);\n }\n start = start === undefined ? start : toInteger(start);\n return baseRest(func, start);\n }\n\n /**\n * Creates a function that invokes `func` with the `this` binding of the\n * create function and an array of arguments much like\n * [`Function#apply`](http://www.ecma-international.org/ecma-262/7.0/#sec-function.prototype.apply).\n *\n * **Note:** This method is based on the\n * [spread operator](https://mdn.io/spread_operator).\n *\n * @static\n * @memberOf _\n * @since 3.2.0\n * @category Function\n * @param {Function} func The function to spread arguments over.\n * @param {number} [start=0] The start position of the spread.\n * @returns {Function} Returns the new function.\n * @example\n *\n * var say = _.spread(function(who, what) {\n * return who + ' says ' + what;\n * });\n *\n * say(['fred', 'hello']);\n * // => 'fred says hello'\n *\n * var numbers = Promise.all([\n * Promise.resolve(40),\n * Promise.resolve(36)\n * ]);\n *\n * numbers.then(_.spread(function(x, y) {\n * return x + y;\n * }));\n * // => a Promise of 76\n */\n function spread(func, start) {\n if (typeof func != 'function') {\n throw new TypeError(FUNC_ERROR_TEXT);\n }\n start = start == null ? 0 : nativeMax(toInteger(start), 0);\n return baseRest(function(args) {\n var array = args[start],\n otherArgs = castSlice(args, 0, start);\n\n if (array) {\n arrayPush(otherArgs, array);\n }\n return apply(func, this, otherArgs);\n });\n }\n\n /**\n * Creates a throttled function that only invokes `func` at most once per\n * every `wait` milliseconds. The throttled function comes with a `cancel`\n * method to cancel delayed `func` invocations and a `flush` method to\n * immediately invoke them. Provide `options` to indicate whether `func`\n * should be invoked on the leading and/or trailing edge of the `wait`\n * timeout. The `func` is invoked with the last arguments provided to the\n * throttled function. Subsequent calls to the throttled function return the\n * result of the last `func` invocation.\n *\n * **Note:** If `leading` and `trailing` options are `true`, `func` is\n * invoked on the trailing edge of the timeout only if the throttled function\n * is invoked more than once during the `wait` timeout.\n *\n * If `wait` is `0` and `leading` is `false`, `func` invocation is deferred\n * until to the next tick, similar to `setTimeout` with a timeout of `0`.\n *\n * See [David Corbacho's article](https://css-tricks.com/debouncing-throttling-explained-examples/)\n * for details over the differences between `_.throttle` and `_.debounce`.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Function\n * @param {Function} func The function to throttle.\n * @param {number} [wait=0] The number of milliseconds to throttle invocations to.\n * @param {Object} [options={}] The options object.\n * @param {boolean} [options.leading=true]\n * Specify invoking on the leading edge of the timeout.\n * @param {boolean} [options.trailing=true]\n * Specify invoking on the trailing edge of the timeout.\n * @returns {Function} Returns the new throttled function.\n * @example\n *\n * // Avoid excessively updating the position while scrolling.\n * jQuery(window).on('scroll', _.throttle(updatePosition, 100));\n *\n * // Invoke `renewToken` when the click event is fired, but not more than once every 5 minutes.\n * var throttled = _.throttle(renewToken, 300000, { 'trailing': false });\n * jQuery(element).on('click', throttled);\n *\n * // Cancel the trailing throttled invocation.\n * jQuery(window).on('popstate', throttled.cancel);\n */\n function throttle(func, wait, options) {\n var leading = true,\n trailing = true;\n\n if (typeof func != 'function') {\n throw new TypeError(FUNC_ERROR_TEXT);\n }\n if (isObject(options)) {\n leading = 'leading' in options ? !!options.leading : leading;\n trailing = 'trailing' in options ? !!options.trailing : trailing;\n }\n return debounce(func, wait, {\n 'leading': leading,\n 'maxWait': wait,\n 'trailing': trailing\n });\n }\n\n /**\n * Creates a function that accepts up to one argument, ignoring any\n * additional arguments.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Function\n * @param {Function} func The function to cap arguments for.\n * @returns {Function} Returns the new capped function.\n * @example\n *\n * _.map(['6', '8', '10'], _.unary(parseInt));\n * // => [6, 8, 10]\n */\n function unary(func) {\n return ary(func, 1);\n }\n\n /**\n * Creates a function that provides `value` to `wrapper` as its first\n * argument. Any additional arguments provided to the function are appended\n * to those provided to the `wrapper`. The wrapper is invoked with the `this`\n * binding of the created function.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Function\n * @param {*} value The value to wrap.\n * @param {Function} [wrapper=identity] The wrapper function.\n * @returns {Function} Returns the new function.\n * @example\n *\n * var p = _.wrap(_.escape, function(func, text) {\n * return '' + func(text) + '
';\n * });\n *\n * p('fred, barney, & pebbles');\n * // => 'fred, barney, & pebbles
'\n */\n function wrap(value, wrapper) {\n return partial(castFunction(wrapper), value);\n }\n\n /*------------------------------------------------------------------------*/\n\n /**\n * Casts `value` as an array if it's not one.\n *\n * @static\n * @memberOf _\n * @since 4.4.0\n * @category Lang\n * @param {*} value The value to inspect.\n * @returns {Array} Returns the cast array.\n * @example\n *\n * _.castArray(1);\n * // => [1]\n *\n * _.castArray({ 'a': 1 });\n * // => [{ 'a': 1 }]\n *\n * _.castArray('abc');\n * // => ['abc']\n *\n * _.castArray(null);\n * // => [null]\n *\n * _.castArray(undefined);\n * // => [undefined]\n *\n * _.castArray();\n * // => []\n *\n * var array = [1, 2, 3];\n * console.log(_.castArray(array) === array);\n * // => true\n */\n function castArray() {\n if (!arguments.length) {\n return [];\n }\n var value = arguments[0];\n return isArray(value) ? value : [value];\n }\n\n /**\n * Creates a shallow clone of `value`.\n *\n * **Note:** This method is loosely based on the\n * [structured clone algorithm](https://mdn.io/Structured_clone_algorithm)\n * and supports cloning arrays, array buffers, booleans, date objects, maps,\n * numbers, `Object` objects, regexes, sets, strings, symbols, and typed\n * arrays. The own enumerable properties of `arguments` objects are cloned\n * as plain objects. An empty object is returned for uncloneable values such\n * as error objects, functions, DOM nodes, and WeakMaps.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Lang\n * @param {*} value The value to clone.\n * @returns {*} Returns the cloned value.\n * @see _.cloneDeep\n * @example\n *\n * var objects = [{ 'a': 1 }, { 'b': 2 }];\n *\n * var shallow = _.clone(objects);\n * console.log(shallow[0] === objects[0]);\n * // => true\n */\n function clone(value) {\n return baseClone(value, CLONE_SYMBOLS_FLAG);\n }\n\n /**\n * This method is like `_.clone` except that it accepts `customizer` which\n * is invoked to produce the cloned value. If `customizer` returns `undefined`,\n * cloning is handled by the method instead. The `customizer` is invoked with\n * up to four arguments; (value [, index|key, object, stack]).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {*} value The value to clone.\n * @param {Function} [customizer] The function to customize cloning.\n * @returns {*} Returns the cloned value.\n * @see _.cloneDeepWith\n * @example\n *\n * function customizer(value) {\n * if (_.isElement(value)) {\n * return value.cloneNode(false);\n * }\n * }\n *\n * var el = _.cloneWith(document.body, customizer);\n *\n * console.log(el === document.body);\n * // => false\n * console.log(el.nodeName);\n * // => 'BODY'\n * console.log(el.childNodes.length);\n * // => 0\n */\n function cloneWith(value, customizer) {\n customizer = typeof customizer == 'function' ? customizer : undefined;\n return baseClone(value, CLONE_SYMBOLS_FLAG, customizer);\n }\n\n /**\n * This method is like `_.clone` except that it recursively clones `value`.\n *\n * @static\n * @memberOf _\n * @since 1.0.0\n * @category Lang\n * @param {*} value The value to recursively clone.\n * @returns {*} Returns the deep cloned value.\n * @see _.clone\n * @example\n *\n * var objects = [{ 'a': 1 }, { 'b': 2 }];\n *\n * var deep = _.cloneDeep(objects);\n * console.log(deep[0] === objects[0]);\n * // => false\n */\n function cloneDeep(value) {\n return baseClone(value, CLONE_DEEP_FLAG | CLONE_SYMBOLS_FLAG);\n }\n\n /**\n * This method is like `_.cloneWith` except that it recursively clones `value`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {*} value The value to recursively clone.\n * @param {Function} [customizer] The function to customize cloning.\n * @returns {*} Returns the deep cloned value.\n * @see _.cloneWith\n * @example\n *\n * function customizer(value) {\n * if (_.isElement(value)) {\n * return value.cloneNode(true);\n * }\n * }\n *\n * var el = _.cloneDeepWith(document.body, customizer);\n *\n * console.log(el === document.body);\n * // => false\n * console.log(el.nodeName);\n * // => 'BODY'\n * console.log(el.childNodes.length);\n * // => 20\n */\n function cloneDeepWith(value, customizer) {\n customizer = typeof customizer == 'function' ? customizer : undefined;\n return baseClone(value, CLONE_DEEP_FLAG | CLONE_SYMBOLS_FLAG, customizer);\n }\n\n /**\n * Checks if `object` conforms to `source` by invoking the predicate\n * properties of `source` with the corresponding property values of `object`.\n *\n * **Note:** This method is equivalent to `_.conforms` when `source` is\n * partially applied.\n *\n * @static\n * @memberOf _\n * @since 4.14.0\n * @category Lang\n * @param {Object} object The object to inspect.\n * @param {Object} source The object of property predicates to conform to.\n * @returns {boolean} Returns `true` if `object` conforms, else `false`.\n * @example\n *\n * var object = { 'a': 1, 'b': 2 };\n *\n * _.conformsTo(object, { 'b': function(n) { return n > 1; } });\n * // => true\n *\n * _.conformsTo(object, { 'b': function(n) { return n > 2; } });\n * // => false\n */\n function conformsTo(object, source) {\n return source == null || baseConformsTo(object, source, keys(source));\n }\n\n /**\n * Performs a\n * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)\n * comparison between two values to determine if they are equivalent.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {*} value The value to compare.\n * @param {*} other The other value to compare.\n * @returns {boolean} Returns `true` if the values are equivalent, else `false`.\n * @example\n *\n * var object = { 'a': 1 };\n * var other = { 'a': 1 };\n *\n * _.eq(object, object);\n * // => true\n *\n * _.eq(object, other);\n * // => false\n *\n * _.eq('a', 'a');\n * // => true\n *\n * _.eq('a', Object('a'));\n * // => false\n *\n * _.eq(NaN, NaN);\n * // => true\n */\n function eq(value, other) {\n return value === other || (value !== value && other !== other);\n }\n\n /**\n * Checks if `value` is greater than `other`.\n *\n * @static\n * @memberOf _\n * @since 3.9.0\n * @category Lang\n * @param {*} value The value to compare.\n * @param {*} other The other value to compare.\n * @returns {boolean} Returns `true` if `value` is greater than `other`,\n * else `false`.\n * @see _.lt\n * @example\n *\n * _.gt(3, 1);\n * // => true\n *\n * _.gt(3, 3);\n * // => false\n *\n * _.gt(1, 3);\n * // => false\n */\n var gt = createRelationalOperation(baseGt);\n\n /**\n * Checks if `value` is greater than or equal to `other`.\n *\n * @static\n * @memberOf _\n * @since 3.9.0\n * @category Lang\n * @param {*} value The value to compare.\n * @param {*} other The other value to compare.\n * @returns {boolean} Returns `true` if `value` is greater than or equal to\n * `other`, else `false`.\n * @see _.lte\n * @example\n *\n * _.gte(3, 1);\n * // => true\n *\n * _.gte(3, 3);\n * // => true\n *\n * _.gte(1, 3);\n * // => false\n */\n var gte = createRelationalOperation(function(value, other) {\n return value >= other;\n });\n\n /**\n * Checks if `value` is likely an `arguments` object.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is an `arguments` object,\n * else `false`.\n * @example\n *\n * _.isArguments(function() { return arguments; }());\n * // => true\n *\n * _.isArguments([1, 2, 3]);\n * // => false\n */\n var isArguments = baseIsArguments(function() { return arguments; }()) ? baseIsArguments : function(value) {\n return isObjectLike(value) && hasOwnProperty.call(value, 'callee') &&\n !propertyIsEnumerable.call(value, 'callee');\n };\n\n /**\n * Checks if `value` is classified as an `Array` object.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is an array, else `false`.\n * @example\n *\n * _.isArray([1, 2, 3]);\n * // => true\n *\n * _.isArray(document.body.children);\n * // => false\n *\n * _.isArray('abc');\n * // => false\n *\n * _.isArray(_.noop);\n * // => false\n */\n var isArray = Array.isArray;\n\n /**\n * Checks if `value` is classified as an `ArrayBuffer` object.\n *\n * @static\n * @memberOf _\n * @since 4.3.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is an array buffer, else `false`.\n * @example\n *\n * _.isArrayBuffer(new ArrayBuffer(2));\n * // => true\n *\n * _.isArrayBuffer(new Array(2));\n * // => false\n */\n var isArrayBuffer = nodeIsArrayBuffer ? baseUnary(nodeIsArrayBuffer) : baseIsArrayBuffer;\n\n /**\n * Checks if `value` is array-like. A value is considered array-like if it's\n * not a function and has a `value.length` that's an integer greater than or\n * equal to `0` and less than or equal to `Number.MAX_SAFE_INTEGER`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is array-like, else `false`.\n * @example\n *\n * _.isArrayLike([1, 2, 3]);\n * // => true\n *\n * _.isArrayLike(document.body.children);\n * // => true\n *\n * _.isArrayLike('abc');\n * // => true\n *\n * _.isArrayLike(_.noop);\n * // => false\n */\n function isArrayLike(value) {\n return value != null && isLength(value.length) && !isFunction(value);\n }\n\n /**\n * This method is like `_.isArrayLike` except that it also checks if `value`\n * is an object.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is an array-like object,\n * else `false`.\n * @example\n *\n * _.isArrayLikeObject([1, 2, 3]);\n * // => true\n *\n * _.isArrayLikeObject(document.body.children);\n * // => true\n *\n * _.isArrayLikeObject('abc');\n * // => false\n *\n * _.isArrayLikeObject(_.noop);\n * // => false\n */\n function isArrayLikeObject(value) {\n return isObjectLike(value) && isArrayLike(value);\n }\n\n /**\n * Checks if `value` is classified as a boolean primitive or object.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a boolean, else `false`.\n * @example\n *\n * _.isBoolean(false);\n * // => true\n *\n * _.isBoolean(null);\n * // => false\n */\n function isBoolean(value) {\n return value === true || value === false ||\n (isObjectLike(value) && baseGetTag(value) == boolTag);\n }\n\n /**\n * Checks if `value` is a buffer.\n *\n * @static\n * @memberOf _\n * @since 4.3.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a buffer, else `false`.\n * @example\n *\n * _.isBuffer(new Buffer(2));\n * // => true\n *\n * _.isBuffer(new Uint8Array(2));\n * // => false\n */\n var isBuffer = nativeIsBuffer || stubFalse;\n\n /**\n * Checks if `value` is classified as a `Date` object.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a date object, else `false`.\n * @example\n *\n * _.isDate(new Date);\n * // => true\n *\n * _.isDate('Mon April 23 2012');\n * // => false\n */\n var isDate = nodeIsDate ? baseUnary(nodeIsDate) : baseIsDate;\n\n /**\n * Checks if `value` is likely a DOM element.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a DOM element, else `false`.\n * @example\n *\n * _.isElement(document.body);\n * // => true\n *\n * _.isElement('');\n * // => false\n */\n function isElement(value) {\n return isObjectLike(value) && value.nodeType === 1 && !isPlainObject(value);\n }\n\n /**\n * Checks if `value` is an empty object, collection, map, or set.\n *\n * Objects are considered empty if they have no own enumerable string keyed\n * properties.\n *\n * Array-like values such as `arguments` objects, arrays, buffers, strings, or\n * jQuery-like collections are considered empty if they have a `length` of `0`.\n * Similarly, maps and sets are considered empty if they have a `size` of `0`.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is empty, else `false`.\n * @example\n *\n * _.isEmpty(null);\n * // => true\n *\n * _.isEmpty(true);\n * // => true\n *\n * _.isEmpty(1);\n * // => true\n *\n * _.isEmpty([1, 2, 3]);\n * // => false\n *\n * _.isEmpty({ 'a': 1 });\n * // => false\n */\n function isEmpty(value) {\n if (value == null) {\n return true;\n }\n if (isArrayLike(value) &&\n (isArray(value) || typeof value == 'string' || typeof value.splice == 'function' ||\n isBuffer(value) || isTypedArray(value) || isArguments(value))) {\n return !value.length;\n }\n var tag = getTag(value);\n if (tag == mapTag || tag == setTag) {\n return !value.size;\n }\n if (isPrototype(value)) {\n return !baseKeys(value).length;\n }\n for (var key in value) {\n if (hasOwnProperty.call(value, key)) {\n return false;\n }\n }\n return true;\n }\n\n /**\n * Performs a deep comparison between two values to determine if they are\n * equivalent.\n *\n * **Note:** This method supports comparing arrays, array buffers, booleans,\n * date objects, error objects, maps, numbers, `Object` objects, regexes,\n * sets, strings, symbols, and typed arrays. `Object` objects are compared\n * by their own, not inherited, enumerable properties. Functions and DOM\n * nodes are compared by strict equality, i.e. `===`.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Lang\n * @param {*} value The value to compare.\n * @param {*} other The other value to compare.\n * @returns {boolean} Returns `true` if the values are equivalent, else `false`.\n * @example\n *\n * var object = { 'a': 1 };\n * var other = { 'a': 1 };\n *\n * _.isEqual(object, other);\n * // => true\n *\n * object === other;\n * // => false\n */\n function isEqual(value, other) {\n return baseIsEqual(value, other);\n }\n\n /**\n * This method is like `_.isEqual` except that it accepts `customizer` which\n * is invoked to compare values. If `customizer` returns `undefined`, comparisons\n * are handled by the method instead. The `customizer` is invoked with up to\n * six arguments: (objValue, othValue [, index|key, object, other, stack]).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {*} value The value to compare.\n * @param {*} other The other value to compare.\n * @param {Function} [customizer] The function to customize comparisons.\n * @returns {boolean} Returns `true` if the values are equivalent, else `false`.\n * @example\n *\n * function isGreeting(value) {\n * return /^h(?:i|ello)$/.test(value);\n * }\n *\n * function customizer(objValue, othValue) {\n * if (isGreeting(objValue) && isGreeting(othValue)) {\n * return true;\n * }\n * }\n *\n * var array = ['hello', 'goodbye'];\n * var other = ['hi', 'goodbye'];\n *\n * _.isEqualWith(array, other, customizer);\n * // => true\n */\n function isEqualWith(value, other, customizer) {\n customizer = typeof customizer == 'function' ? customizer : undefined;\n var result = customizer ? customizer(value, other) : undefined;\n return result === undefined ? baseIsEqual(value, other, undefined, customizer) : !!result;\n }\n\n /**\n * Checks if `value` is an `Error`, `EvalError`, `RangeError`, `ReferenceError`,\n * `SyntaxError`, `TypeError`, or `URIError` object.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is an error object, else `false`.\n * @example\n *\n * _.isError(new Error);\n * // => true\n *\n * _.isError(Error);\n * // => false\n */\n function isError(value) {\n if (!isObjectLike(value)) {\n return false;\n }\n var tag = baseGetTag(value);\n return tag == errorTag || tag == domExcTag ||\n (typeof value.message == 'string' && typeof value.name == 'string' && !isPlainObject(value));\n }\n\n /**\n * Checks if `value` is a finite primitive number.\n *\n * **Note:** This method is based on\n * [`Number.isFinite`](https://mdn.io/Number/isFinite).\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a finite number, else `false`.\n * @example\n *\n * _.isFinite(3);\n * // => true\n *\n * _.isFinite(Number.MIN_VALUE);\n * // => true\n *\n * _.isFinite(Infinity);\n * // => false\n *\n * _.isFinite('3');\n * // => false\n */\n function isFinite(value) {\n return typeof value == 'number' && nativeIsFinite(value);\n }\n\n /**\n * Checks if `value` is classified as a `Function` object.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a function, else `false`.\n * @example\n *\n * _.isFunction(_);\n * // => true\n *\n * _.isFunction(/abc/);\n * // => false\n */\n function isFunction(value) {\n if (!isObject(value)) {\n return false;\n }\n // The use of `Object#toString` avoids issues with the `typeof` operator\n // in Safari 9 which returns 'object' for typed arrays and other constructors.\n var tag = baseGetTag(value);\n return tag == funcTag || tag == genTag || tag == asyncTag || tag == proxyTag;\n }\n\n /**\n * Checks if `value` is an integer.\n *\n * **Note:** This method is based on\n * [`Number.isInteger`](https://mdn.io/Number/isInteger).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is an integer, else `false`.\n * @example\n *\n * _.isInteger(3);\n * // => true\n *\n * _.isInteger(Number.MIN_VALUE);\n * // => false\n *\n * _.isInteger(Infinity);\n * // => false\n *\n * _.isInteger('3');\n * // => false\n */\n function isInteger(value) {\n return typeof value == 'number' && value == toInteger(value);\n }\n\n /**\n * Checks if `value` is a valid array-like length.\n *\n * **Note:** This method is loosely based on\n * [`ToLength`](http://ecma-international.org/ecma-262/7.0/#sec-tolength).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a valid length, else `false`.\n * @example\n *\n * _.isLength(3);\n * // => true\n *\n * _.isLength(Number.MIN_VALUE);\n * // => false\n *\n * _.isLength(Infinity);\n * // => false\n *\n * _.isLength('3');\n * // => false\n */\n function isLength(value) {\n return typeof value == 'number' &&\n value > -1 && value % 1 == 0 && value <= MAX_SAFE_INTEGER;\n }\n\n /**\n * Checks if `value` is the\n * [language type](http://www.ecma-international.org/ecma-262/7.0/#sec-ecmascript-language-types)\n * of `Object`. (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is an object, else `false`.\n * @example\n *\n * _.isObject({});\n * // => true\n *\n * _.isObject([1, 2, 3]);\n * // => true\n *\n * _.isObject(_.noop);\n * // => true\n *\n * _.isObject(null);\n * // => false\n */\n function isObject(value) {\n var type = typeof value;\n return value != null && (type == 'object' || type == 'function');\n }\n\n /**\n * Checks if `value` is object-like. A value is object-like if it's not `null`\n * and has a `typeof` result of \"object\".\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is object-like, else `false`.\n * @example\n *\n * _.isObjectLike({});\n * // => true\n *\n * _.isObjectLike([1, 2, 3]);\n * // => true\n *\n * _.isObjectLike(_.noop);\n * // => false\n *\n * _.isObjectLike(null);\n * // => false\n */\n function isObjectLike(value) {\n return value != null && typeof value == 'object';\n }\n\n /**\n * Checks if `value` is classified as a `Map` object.\n *\n * @static\n * @memberOf _\n * @since 4.3.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a map, else `false`.\n * @example\n *\n * _.isMap(new Map);\n * // => true\n *\n * _.isMap(new WeakMap);\n * // => false\n */\n var isMap = nodeIsMap ? baseUnary(nodeIsMap) : baseIsMap;\n\n /**\n * Performs a partial deep comparison between `object` and `source` to\n * determine if `object` contains equivalent property values.\n *\n * **Note:** This method is equivalent to `_.matches` when `source` is\n * partially applied.\n *\n * Partial comparisons will match empty array and empty object `source`\n * values against any array or object value, respectively. See `_.isEqual`\n * for a list of supported value comparisons.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Lang\n * @param {Object} object The object to inspect.\n * @param {Object} source The object of property values to match.\n * @returns {boolean} Returns `true` if `object` is a match, else `false`.\n * @example\n *\n * var object = { 'a': 1, 'b': 2 };\n *\n * _.isMatch(object, { 'b': 2 });\n * // => true\n *\n * _.isMatch(object, { 'b': 1 });\n * // => false\n */\n function isMatch(object, source) {\n return object === source || baseIsMatch(object, source, getMatchData(source));\n }\n\n /**\n * This method is like `_.isMatch` except that it accepts `customizer` which\n * is invoked to compare values. If `customizer` returns `undefined`, comparisons\n * are handled by the method instead. The `customizer` is invoked with five\n * arguments: (objValue, srcValue, index|key, object, source).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {Object} object The object to inspect.\n * @param {Object} source The object of property values to match.\n * @param {Function} [customizer] The function to customize comparisons.\n * @returns {boolean} Returns `true` if `object` is a match, else `false`.\n * @example\n *\n * function isGreeting(value) {\n * return /^h(?:i|ello)$/.test(value);\n * }\n *\n * function customizer(objValue, srcValue) {\n * if (isGreeting(objValue) && isGreeting(srcValue)) {\n * return true;\n * }\n * }\n *\n * var object = { 'greeting': 'hello' };\n * var source = { 'greeting': 'hi' };\n *\n * _.isMatchWith(object, source, customizer);\n * // => true\n */\n function isMatchWith(object, source, customizer) {\n customizer = typeof customizer == 'function' ? customizer : undefined;\n return baseIsMatch(object, source, getMatchData(source), customizer);\n }\n\n /**\n * Checks if `value` is `NaN`.\n *\n * **Note:** This method is based on\n * [`Number.isNaN`](https://mdn.io/Number/isNaN) and is not the same as\n * global [`isNaN`](https://mdn.io/isNaN) which returns `true` for\n * `undefined` and other non-number values.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is `NaN`, else `false`.\n * @example\n *\n * _.isNaN(NaN);\n * // => true\n *\n * _.isNaN(new Number(NaN));\n * // => true\n *\n * isNaN(undefined);\n * // => true\n *\n * _.isNaN(undefined);\n * // => false\n */\n function isNaN(value) {\n // An `NaN` primitive is the only value that is not equal to itself.\n // Perform the `toStringTag` check first to avoid errors with some\n // ActiveX objects in IE.\n return isNumber(value) && value != +value;\n }\n\n /**\n * Checks if `value` is a pristine native function.\n *\n * **Note:** This method can't reliably detect native functions in the presence\n * of the core-js package because core-js circumvents this kind of detection.\n * Despite multiple requests, the core-js maintainer has made it clear: any\n * attempt to fix the detection will be obstructed. As a result, we're left\n * with little choice but to throw an error. Unfortunately, this also affects\n * packages, like [babel-polyfill](https://www.npmjs.com/package/babel-polyfill),\n * which rely on core-js.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a native function,\n * else `false`.\n * @example\n *\n * _.isNative(Array.prototype.push);\n * // => true\n *\n * _.isNative(_);\n * // => false\n */\n function isNative(value) {\n if (isMaskable(value)) {\n throw new Error(CORE_ERROR_TEXT);\n }\n return baseIsNative(value);\n }\n\n /**\n * Checks if `value` is `null`.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is `null`, else `false`.\n * @example\n *\n * _.isNull(null);\n * // => true\n *\n * _.isNull(void 0);\n * // => false\n */\n function isNull(value) {\n return value === null;\n }\n\n /**\n * Checks if `value` is `null` or `undefined`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is nullish, else `false`.\n * @example\n *\n * _.isNil(null);\n * // => true\n *\n * _.isNil(void 0);\n * // => true\n *\n * _.isNil(NaN);\n * // => false\n */\n function isNil(value) {\n return value == null;\n }\n\n /**\n * Checks if `value` is classified as a `Number` primitive or object.\n *\n * **Note:** To exclude `Infinity`, `-Infinity`, and `NaN`, which are\n * classified as numbers, use the `_.isFinite` method.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a number, else `false`.\n * @example\n *\n * _.isNumber(3);\n * // => true\n *\n * _.isNumber(Number.MIN_VALUE);\n * // => true\n *\n * _.isNumber(Infinity);\n * // => true\n *\n * _.isNumber('3');\n * // => false\n */\n function isNumber(value) {\n return typeof value == 'number' ||\n (isObjectLike(value) && baseGetTag(value) == numberTag);\n }\n\n /**\n * Checks if `value` is a plain object, that is, an object created by the\n * `Object` constructor or one with a `[[Prototype]]` of `null`.\n *\n * @static\n * @memberOf _\n * @since 0.8.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.\n * @example\n *\n * function Foo() {\n * this.a = 1;\n * }\n *\n * _.isPlainObject(new Foo);\n * // => false\n *\n * _.isPlainObject([1, 2, 3]);\n * // => false\n *\n * _.isPlainObject({ 'x': 0, 'y': 0 });\n * // => true\n *\n * _.isPlainObject(Object.create(null));\n * // => true\n */\n function isPlainObject(value) {\n if (!isObjectLike(value) || baseGetTag(value) != objectTag) {\n return false;\n }\n var proto = getPrototype(value);\n if (proto === null) {\n return true;\n }\n var Ctor = hasOwnProperty.call(proto, 'constructor') && proto.constructor;\n return typeof Ctor == 'function' && Ctor instanceof Ctor &&\n funcToString.call(Ctor) == objectCtorString;\n }\n\n /**\n * Checks if `value` is classified as a `RegExp` object.\n *\n * @static\n * @memberOf _\n * @since 0.1.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a regexp, else `false`.\n * @example\n *\n * _.isRegExp(/abc/);\n * // => true\n *\n * _.isRegExp('/abc/');\n * // => false\n */\n var isRegExp = nodeIsRegExp ? baseUnary(nodeIsRegExp) : baseIsRegExp;\n\n /**\n * Checks if `value` is a safe integer. An integer is safe if it's an IEEE-754\n * double precision number which isn't the result of a rounded unsafe integer.\n *\n * **Note:** This method is based on\n * [`Number.isSafeInteger`](https://mdn.io/Number/isSafeInteger).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a safe integer, else `false`.\n * @example\n *\n * _.isSafeInteger(3);\n * // => true\n *\n * _.isSafeInteger(Number.MIN_VALUE);\n * // => false\n *\n * _.isSafeInteger(Infinity);\n * // => false\n *\n * _.isSafeInteger('3');\n * // => false\n */\n function isSafeInteger(value) {\n return isInteger(value) && value >= -MAX_SAFE_INTEGER && value <= MAX_SAFE_INTEGER;\n }\n\n /**\n * Checks if `value` is classified as a `Set` object.\n *\n * @static\n * @memberOf _\n * @since 4.3.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a set, else `false`.\n * @example\n *\n * _.isSet(new Set);\n * // => true\n *\n * _.isSet(new WeakSet);\n * // => false\n */\n var isSet = nodeIsSet ? baseUnary(nodeIsSet) : baseIsSet;\n\n /**\n * Checks if `value` is classified as a `String` primitive or object.\n *\n * @static\n * @since 0.1.0\n * @memberOf _\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a string, else `false`.\n * @example\n *\n * _.isString('abc');\n * // => true\n *\n * _.isString(1);\n * // => false\n */\n function isString(value) {\n return typeof value == 'string' ||\n (!isArray(value) && isObjectLike(value) && baseGetTag(value) == stringTag);\n }\n\n /**\n * Checks if `value` is classified as a `Symbol` primitive or object.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a symbol, else `false`.\n * @example\n *\n * _.isSymbol(Symbol.iterator);\n * // => true\n *\n * _.isSymbol('abc');\n * // => false\n */\n function isSymbol(value) {\n return typeof value == 'symbol' ||\n (isObjectLike(value) && baseGetTag(value) == symbolTag);\n }\n\n /**\n * Checks if `value` is classified as a typed array.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a typed array, else `false`.\n * @example\n *\n * _.isTypedArray(new Uint8Array);\n * // => true\n *\n * _.isTypedArray([]);\n * // => false\n */\n var isTypedArray = nodeIsTypedArray ? baseUnary(nodeIsTypedArray) : baseIsTypedArray;\n\n /**\n * Checks if `value` is `undefined`.\n *\n * @static\n * @since 0.1.0\n * @memberOf _\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is `undefined`, else `false`.\n * @example\n *\n * _.isUndefined(void 0);\n * // => true\n *\n * _.isUndefined(null);\n * // => false\n */\n function isUndefined(value) {\n return value === undefined;\n }\n\n /**\n * Checks if `value` is classified as a `WeakMap` object.\n *\n * @static\n * @memberOf _\n * @since 4.3.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a weak map, else `false`.\n * @example\n *\n * _.isWeakMap(new WeakMap);\n * // => true\n *\n * _.isWeakMap(new Map);\n * // => false\n */\n function isWeakMap(value) {\n return isObjectLike(value) && getTag(value) == weakMapTag;\n }\n\n /**\n * Checks if `value` is classified as a `WeakSet` object.\n *\n * @static\n * @memberOf _\n * @since 4.3.0\n * @category Lang\n * @param {*} value The value to check.\n * @returns {boolean} Returns `true` if `value` is a weak set, else `false`.\n * @example\n *\n * _.isWeakSet(new WeakSet);\n * // => true\n *\n * _.isWeakSet(new Set);\n * // => false\n */\n function isWeakSet(value) {\n return isObjectLike(value) && baseGetTag(value) == weakSetTag;\n }\n\n /**\n * Checks if `value` is less than `other`.\n *\n * @static\n * @memberOf _\n * @since 3.9.0\n * @category Lang\n * @param {*} value The value to compare.\n * @param {*} other The other value to compare.\n * @returns {boolean} Returns `true` if `value` is less than `other`,\n * else `false`.\n * @see _.gt\n * @example\n *\n * _.lt(1, 3);\n * // => true\n *\n * _.lt(3, 3);\n * // => false\n *\n * _.lt(3, 1);\n * // => false\n */\n var lt = createRelationalOperation(baseLt);\n\n /**\n * Checks if `value` is less than or equal to `other`.\n *\n * @static\n * @memberOf _\n * @since 3.9.0\n * @category Lang\n * @param {*} value The value to compare.\n * @param {*} other The other value to compare.\n * @returns {boolean} Returns `true` if `value` is less than or equal to\n * `other`, else `false`.\n * @see _.gte\n * @example\n *\n * _.lte(1, 3);\n * // => true\n *\n * _.lte(3, 3);\n * // => true\n *\n * _.lte(3, 1);\n * // => false\n */\n var lte = createRelationalOperation(function(value, other) {\n return value <= other;\n });\n\n /**\n * Converts `value` to an array.\n *\n * @static\n * @since 0.1.0\n * @memberOf _\n * @category Lang\n * @param {*} value The value to convert.\n * @returns {Array} Returns the converted array.\n * @example\n *\n * _.toArray({ 'a': 1, 'b': 2 });\n * // => [1, 2]\n *\n * _.toArray('abc');\n * // => ['a', 'b', 'c']\n *\n * _.toArray(1);\n * // => []\n *\n * _.toArray(null);\n * // => []\n */\n function toArray(value) {\n if (!value) {\n return [];\n }\n if (isArrayLike(value)) {\n return isString(value) ? stringToArray(value) : copyArray(value);\n }\n if (symIterator && value[symIterator]) {\n return iteratorToArray(value[symIterator]());\n }\n var tag = getTag(value),\n func = tag == mapTag ? mapToArray : (tag == setTag ? setToArray : values);\n\n return func(value);\n }\n\n /**\n * Converts `value` to a finite number.\n *\n * @static\n * @memberOf _\n * @since 4.12.0\n * @category Lang\n * @param {*} value The value to convert.\n * @returns {number} Returns the converted number.\n * @example\n *\n * _.toFinite(3.2);\n * // => 3.2\n *\n * _.toFinite(Number.MIN_VALUE);\n * // => 5e-324\n *\n * _.toFinite(Infinity);\n * // => 1.7976931348623157e+308\n *\n * _.toFinite('3.2');\n * // => 3.2\n */\n function toFinite(value) {\n if (!value) {\n return value === 0 ? value : 0;\n }\n value = toNumber(value);\n if (value === INFINITY || value === -INFINITY) {\n var sign = (value < 0 ? -1 : 1);\n return sign * MAX_INTEGER;\n }\n return value === value ? value : 0;\n }\n\n /**\n * Converts `value` to an integer.\n *\n * **Note:** This method is loosely based on\n * [`ToInteger`](http://www.ecma-international.org/ecma-262/7.0/#sec-tointeger).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {*} value The value to convert.\n * @returns {number} Returns the converted integer.\n * @example\n *\n * _.toInteger(3.2);\n * // => 3\n *\n * _.toInteger(Number.MIN_VALUE);\n * // => 0\n *\n * _.toInteger(Infinity);\n * // => 1.7976931348623157e+308\n *\n * _.toInteger('3.2');\n * // => 3\n */\n function toInteger(value) {\n var result = toFinite(value),\n remainder = result % 1;\n\n return result === result ? (remainder ? result - remainder : result) : 0;\n }\n\n /**\n * Converts `value` to an integer suitable for use as the length of an\n * array-like object.\n *\n * **Note:** This method is based on\n * [`ToLength`](http://ecma-international.org/ecma-262/7.0/#sec-tolength).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {*} value The value to convert.\n * @returns {number} Returns the converted integer.\n * @example\n *\n * _.toLength(3.2);\n * // => 3\n *\n * _.toLength(Number.MIN_VALUE);\n * // => 0\n *\n * _.toLength(Infinity);\n * // => 4294967295\n *\n * _.toLength('3.2');\n * // => 3\n */\n function toLength(value) {\n return value ? baseClamp(toInteger(value), 0, MAX_ARRAY_LENGTH) : 0;\n }\n\n /**\n * Converts `value` to a number.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {*} value The value to process.\n * @returns {number} Returns the number.\n * @example\n *\n * _.toNumber(3.2);\n * // => 3.2\n *\n * _.toNumber(Number.MIN_VALUE);\n * // => 5e-324\n *\n * _.toNumber(Infinity);\n * // => Infinity\n *\n * _.toNumber('3.2');\n * // => 3.2\n */\n function toNumber(value) {\n if (typeof value == 'number') {\n return value;\n }\n if (isSymbol(value)) {\n return NAN;\n }\n if (isObject(value)) {\n var other = typeof value.valueOf == 'function' ? value.valueOf() : value;\n value = isObject(other) ? (other + '') : other;\n }\n if (typeof value != 'string') {\n return value === 0 ? value : +value;\n }\n value = value.replace(reTrim, '');\n var isBinary = reIsBinary.test(value);\n return (isBinary || reIsOctal.test(value))\n ? freeParseInt(value.slice(2), isBinary ? 2 : 8)\n : (reIsBadHex.test(value) ? NAN : +value);\n }\n\n /**\n * Converts `value` to a plain object flattening inherited enumerable string\n * keyed properties of `value` to own properties of the plain object.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Lang\n * @param {*} value The value to convert.\n * @returns {Object} Returns the converted plain object.\n * @example\n *\n * function Foo() {\n * this.b = 2;\n * }\n *\n * Foo.prototype.c = 3;\n *\n * _.assign({ 'a': 1 }, new Foo);\n * // => { 'a': 1, 'b': 2 }\n *\n * _.assign({ 'a': 1 }, _.toPlainObject(new Foo));\n * // => { 'a': 1, 'b': 2, 'c': 3 }\n */\n function toPlainObject(value) {\n return copyObject(value, keysIn(value));\n }\n\n /**\n * Converts `value` to a safe integer. A safe integer can be compared and\n * represented correctly.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {*} value The value to convert.\n * @returns {number} Returns the converted integer.\n * @example\n *\n * _.toSafeInteger(3.2);\n * // => 3\n *\n * _.toSafeInteger(Number.MIN_VALUE);\n * // => 0\n *\n * _.toSafeInteger(Infinity);\n * // => 9007199254740991\n *\n * _.toSafeInteger('3.2');\n * // => 3\n */\n function toSafeInteger(value) {\n return value\n ? baseClamp(toInteger(value), -MAX_SAFE_INTEGER, MAX_SAFE_INTEGER)\n : (value === 0 ? value : 0);\n }\n\n /**\n * Converts `value` to a string. An empty string is returned for `null`\n * and `undefined` values. The sign of `-0` is preserved.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Lang\n * @param {*} value The value to convert.\n * @returns {string} Returns the converted string.\n * @example\n *\n * _.toString(null);\n * // => ''\n *\n * _.toString(-0);\n * // => '-0'\n *\n * _.toString([1, 2, 3]);\n * // => '1,2,3'\n */\n function toString(value) {\n return value == null ? '' : baseToString(value);\n }\n\n /*------------------------------------------------------------------------*/\n\n /**\n * Assigns own enumerable string keyed properties of source objects to the\n * destination object. Source objects are applied from left to right.\n * Subsequent sources overwrite property assignments of previous sources.\n *\n * **Note:** This method mutates `object` and is loosely based on\n * [`Object.assign`](https://mdn.io/Object/assign).\n *\n * @static\n * @memberOf _\n * @since 0.10.0\n * @category Object\n * @param {Object} object The destination object.\n * @param {...Object} [sources] The source objects.\n * @returns {Object} Returns `object`.\n * @see _.assignIn\n * @example\n *\n * function Foo() {\n * this.a = 1;\n * }\n *\n * function Bar() {\n * this.c = 3;\n * }\n *\n * Foo.prototype.b = 2;\n * Bar.prototype.d = 4;\n *\n * _.assign({ 'a': 0 }, new Foo, new Bar);\n * // => { 'a': 1, 'c': 3 }\n */\n var assign = createAssigner(function(object, source) {\n if (isPrototype(source) || isArrayLike(source)) {\n copyObject(source, keys(source), object);\n return;\n }\n for (var key in source) {\n if (hasOwnProperty.call(source, key)) {\n assignValue(object, key, source[key]);\n }\n }\n });\n\n /**\n * This method is like `_.assign` except that it iterates over own and\n * inherited source properties.\n *\n * **Note:** This method mutates `object`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @alias extend\n * @category Object\n * @param {Object} object The destination object.\n * @param {...Object} [sources] The source objects.\n * @returns {Object} Returns `object`.\n * @see _.assign\n * @example\n *\n * function Foo() {\n * this.a = 1;\n * }\n *\n * function Bar() {\n * this.c = 3;\n * }\n *\n * Foo.prototype.b = 2;\n * Bar.prototype.d = 4;\n *\n * _.assignIn({ 'a': 0 }, new Foo, new Bar);\n * // => { 'a': 1, 'b': 2, 'c': 3, 'd': 4 }\n */\n var assignIn = createAssigner(function(object, source) {\n copyObject(source, keysIn(source), object);\n });\n\n /**\n * This method is like `_.assignIn` except that it accepts `customizer`\n * which is invoked to produce the assigned values. If `customizer` returns\n * `undefined`, assignment is handled by the method instead. The `customizer`\n * is invoked with five arguments: (objValue, srcValue, key, object, source).\n *\n * **Note:** This method mutates `object`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @alias extendWith\n * @category Object\n * @param {Object} object The destination object.\n * @param {...Object} sources The source objects.\n * @param {Function} [customizer] The function to customize assigned values.\n * @returns {Object} Returns `object`.\n * @see _.assignWith\n * @example\n *\n * function customizer(objValue, srcValue) {\n * return _.isUndefined(objValue) ? srcValue : objValue;\n * }\n *\n * var defaults = _.partialRight(_.assignInWith, customizer);\n *\n * defaults({ 'a': 1 }, { 'b': 2 }, { 'a': 3 });\n * // => { 'a': 1, 'b': 2 }\n */\n var assignInWith = createAssigner(function(object, source, srcIndex, customizer) {\n copyObject(source, keysIn(source), object, customizer);\n });\n\n /**\n * This method is like `_.assign` except that it accepts `customizer`\n * which is invoked to produce the assigned values. If `customizer` returns\n * `undefined`, assignment is handled by the method instead. The `customizer`\n * is invoked with five arguments: (objValue, srcValue, key, object, source).\n *\n * **Note:** This method mutates `object`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Object\n * @param {Object} object The destination object.\n * @param {...Object} sources The source objects.\n * @param {Function} [customizer] The function to customize assigned values.\n * @returns {Object} Returns `object`.\n * @see _.assignInWith\n * @example\n *\n * function customizer(objValue, srcValue) {\n * return _.isUndefined(objValue) ? srcValue : objValue;\n * }\n *\n * var defaults = _.partialRight(_.assignWith, customizer);\n *\n * defaults({ 'a': 1 }, { 'b': 2 }, { 'a': 3 });\n * // => { 'a': 1, 'b': 2 }\n */\n var assignWith = createAssigner(function(object, source, srcIndex, customizer) {\n copyObject(source, keys(source), object, customizer);\n });\n\n /**\n * Creates an array of values corresponding to `paths` of `object`.\n *\n * @static\n * @memberOf _\n * @since 1.0.0\n * @category Object\n * @param {Object} object The object to iterate over.\n * @param {...(string|string[])} [paths] The property paths to pick.\n * @returns {Array} Returns the picked values.\n * @example\n *\n * var object = { 'a': [{ 'b': { 'c': 3 } }, 4] };\n *\n * _.at(object, ['a[0].b.c', 'a[1]']);\n * // => [3, 4]\n */\n var at = flatRest(baseAt);\n\n /**\n * Creates an object that inherits from the `prototype` object. If a\n * `properties` object is given, its own enumerable string keyed properties\n * are assigned to the created object.\n *\n * @static\n * @memberOf _\n * @since 2.3.0\n * @category Object\n * @param {Object} prototype The object to inherit from.\n * @param {Object} [properties] The properties to assign to the object.\n * @returns {Object} Returns the new object.\n * @example\n *\n * function Shape() {\n * this.x = 0;\n * this.y = 0;\n * }\n *\n * function Circle() {\n * Shape.call(this);\n * }\n *\n * Circle.prototype = _.create(Shape.prototype, {\n * 'constructor': Circle\n * });\n *\n * var circle = new Circle;\n * circle instanceof Circle;\n * // => true\n *\n * circle instanceof Shape;\n * // => true\n */\n function create(prototype, properties) {\n var result = baseCreate(prototype);\n return properties == null ? result : baseAssign(result, properties);\n }\n\n /**\n * Assigns own and inherited enumerable string keyed properties of source\n * objects to the destination object for all destination properties that\n * resolve to `undefined`. Source objects are applied from left to right.\n * Once a property is set, additional values of the same property are ignored.\n *\n * **Note:** This method mutates `object`.\n *\n * @static\n * @since 0.1.0\n * @memberOf _\n * @category Object\n * @param {Object} object The destination object.\n * @param {...Object} [sources] The source objects.\n * @returns {Object} Returns `object`.\n * @see _.defaultsDeep\n * @example\n *\n * _.defaults({ 'a': 1 }, { 'b': 2 }, { 'a': 3 });\n * // => { 'a': 1, 'b': 2 }\n */\n var defaults = baseRest(function(object, sources) {\n object = Object(object);\n\n var index = -1;\n var length = sources.length;\n var guard = length > 2 ? sources[2] : undefined;\n\n if (guard && isIterateeCall(sources[0], sources[1], guard)) {\n length = 1;\n }\n\n while (++index < length) {\n var source = sources[index];\n var props = keysIn(source);\n var propsIndex = -1;\n var propsLength = props.length;\n\n while (++propsIndex < propsLength) {\n var key = props[propsIndex];\n var value = object[key];\n\n if (value === undefined ||\n (eq(value, objectProto[key]) && !hasOwnProperty.call(object, key))) {\n object[key] = source[key];\n }\n }\n }\n\n return object;\n });\n\n /**\n * This method is like `_.defaults` except that it recursively assigns\n * default properties.\n *\n * **Note:** This method mutates `object`.\n *\n * @static\n * @memberOf _\n * @since 3.10.0\n * @category Object\n * @param {Object} object The destination object.\n * @param {...Object} [sources] The source objects.\n * @returns {Object} Returns `object`.\n * @see _.defaults\n * @example\n *\n * _.defaultsDeep({ 'a': { 'b': 2 } }, { 'a': { 'b': 1, 'c': 3 } });\n * // => { 'a': { 'b': 2, 'c': 3 } }\n */\n var defaultsDeep = baseRest(function(args) {\n args.push(undefined, customDefaultsMerge);\n return apply(mergeWith, undefined, args);\n });\n\n /**\n * This method is like `_.find` except that it returns the key of the first\n * element `predicate` returns truthy for instead of the element itself.\n *\n * @static\n * @memberOf _\n * @since 1.1.0\n * @category Object\n * @param {Object} object The object to inspect.\n * @param {Function} [predicate=_.identity] The function invoked per iteration.\n * @returns {string|undefined} Returns the key of the matched element,\n * else `undefined`.\n * @example\n *\n * var users = {\n * 'barney': { 'age': 36, 'active': true },\n * 'fred': { 'age': 40, 'active': false },\n * 'pebbles': { 'age': 1, 'active': true }\n * };\n *\n * _.findKey(users, function(o) { return o.age < 40; });\n * // => 'barney' (iteration order is not guaranteed)\n *\n * // The `_.matches` iteratee shorthand.\n * _.findKey(users, { 'age': 1, 'active': true });\n * // => 'pebbles'\n *\n * // The `_.matchesProperty` iteratee shorthand.\n * _.findKey(users, ['active', false]);\n * // => 'fred'\n *\n * // The `_.property` iteratee shorthand.\n * _.findKey(users, 'active');\n * // => 'barney'\n */\n function findKey(object, predicate) {\n return baseFindKey(object, getIteratee(predicate, 3), baseForOwn);\n }\n\n /**\n * This method is like `_.findKey` except that it iterates over elements of\n * a collection in the opposite order.\n *\n * @static\n * @memberOf _\n * @since 2.0.0\n * @category Object\n * @param {Object} object The object to inspect.\n * @param {Function} [predicate=_.identity] The function invoked per iteration.\n * @returns {string|undefined} Returns the key of the matched element,\n * else `undefined`.\n * @example\n *\n * var users = {\n * 'barney': { 'age': 36, 'active': true },\n * 'fred': { 'age': 40, 'active': false },\n * 'pebbles': { 'age': 1, 'active': true }\n * };\n *\n * _.findLastKey(users, function(o) { return o.age < 40; });\n * // => returns 'pebbles' assuming `_.findKey` returns 'barney'\n *\n * // The `_.matches` iteratee shorthand.\n * _.findLastKey(users, { 'age': 36, 'active': true });\n * // => 'barney'\n *\n * // The `_.matchesProperty` iteratee shorthand.\n * _.findLastKey(users, ['active', false]);\n * // => 'fred'\n *\n * // The `_.property` iteratee shorthand.\n * _.findLastKey(users, 'active');\n * // => 'pebbles'\n */\n function findLastKey(object, predicate) {\n return baseFindKey(object, getIteratee(predicate, 3), baseForOwnRight);\n }\n\n /**\n * Iterates over own and inherited enumerable string keyed properties of an\n * object and invokes `iteratee` for each property. The iteratee is invoked\n * with three arguments: (value, key, object). Iteratee functions may exit\n * iteration early by explicitly returning `false`.\n *\n * @static\n * @memberOf _\n * @since 0.3.0\n * @category Object\n * @param {Object} object The object to iterate over.\n * @param {Function} [iteratee=_.identity] The function invoked per iteration.\n * @returns {Object} Returns `object`.\n * @see _.forInRight\n * @example\n *\n * function Foo() {\n * this.a = 1;\n * this.b = 2;\n * }\n *\n * Foo.prototype.c = 3;\n *\n * _.forIn(new Foo, function(value, key) {\n * console.log(key);\n * });\n * // => Logs 'a', 'b', then 'c' (iteration order is not guaranteed).\n */\n function forIn(object, iteratee) {\n return object == null\n ? object\n : baseFor(object, getIteratee(iteratee, 3), keysIn);\n }\n\n /**\n * This method is like `_.forIn` except that it iterates over properties of\n * `object` in the opposite order.\n *\n * @static\n * @memberOf _\n * @since 2.0.0\n * @category Object\n * @param {Object} object The object to iterate over.\n * @param {Function} [iteratee=_.identity] The function invoked per iteration.\n * @returns {Object} Returns `object`.\n * @see _.forIn\n * @example\n *\n * function Foo() {\n * this.a = 1;\n * this.b = 2;\n * }\n *\n * Foo.prototype.c = 3;\n *\n * _.forInRight(new Foo, function(value, key) {\n * console.log(key);\n * });\n * // => Logs 'c', 'b', then 'a' assuming `_.forIn` logs 'a', 'b', then 'c'.\n */\n function forInRight(object, iteratee) {\n return object == null\n ? object\n : baseForRight(object, getIteratee(iteratee, 3), keysIn);\n }\n\n /**\n * Iterates over own enumerable string keyed properties of an object and\n * invokes `iteratee` for each property. The iteratee is invoked with three\n * arguments: (value, key, object). Iteratee functions may exit iteration\n * early by explicitly returning `false`.\n *\n * @static\n * @memberOf _\n * @since 0.3.0\n * @category Object\n * @param {Object} object The object to iterate over.\n * @param {Function} [iteratee=_.identity] The function invoked per iteration.\n * @returns {Object} Returns `object`.\n * @see _.forOwnRight\n * @example\n *\n * function Foo() {\n * this.a = 1;\n * this.b = 2;\n * }\n *\n * Foo.prototype.c = 3;\n *\n * _.forOwn(new Foo, function(value, key) {\n * console.log(key);\n * });\n * // => Logs 'a' then 'b' (iteration order is not guaranteed).\n */\n function forOwn(object, iteratee) {\n return object && baseForOwn(object, getIteratee(iteratee, 3));\n }\n\n /**\n * This method is like `_.forOwn` except that it iterates over properties of\n * `object` in the opposite order.\n *\n * @static\n * @memberOf _\n * @since 2.0.0\n * @category Object\n * @param {Object} object The object to iterate over.\n * @param {Function} [iteratee=_.identity] The function invoked per iteration.\n * @returns {Object} Returns `object`.\n * @see _.forOwn\n * @example\n *\n * function Foo() {\n * this.a = 1;\n * this.b = 2;\n * }\n *\n * Foo.prototype.c = 3;\n *\n * _.forOwnRight(new Foo, function(value, key) {\n * console.log(key);\n * });\n * // => Logs 'b' then 'a' assuming `_.forOwn` logs 'a' then 'b'.\n */\n function forOwnRight(object, iteratee) {\n return object && baseForOwnRight(object, getIteratee(iteratee, 3));\n }\n\n /**\n * Creates an array of function property names from own enumerable properties\n * of `object`.\n *\n * @static\n * @since 0.1.0\n * @memberOf _\n * @category Object\n * @param {Object} object The object to inspect.\n * @returns {Array} Returns the function names.\n * @see _.functionsIn\n * @example\n *\n * function Foo() {\n * this.a = _.constant('a');\n * this.b = _.constant('b');\n * }\n *\n * Foo.prototype.c = _.constant('c');\n *\n * _.functions(new Foo);\n * // => ['a', 'b']\n */\n function functions(object) {\n return object == null ? [] : baseFunctions(object, keys(object));\n }\n\n /**\n * Creates an array of function property names from own and inherited\n * enumerable properties of `object`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Object\n * @param {Object} object The object to inspect.\n * @returns {Array} Returns the function names.\n * @see _.functions\n * @example\n *\n * function Foo() {\n * this.a = _.constant('a');\n * this.b = _.constant('b');\n * }\n *\n * Foo.prototype.c = _.constant('c');\n *\n * _.functionsIn(new Foo);\n * // => ['a', 'b', 'c']\n */\n function functionsIn(object) {\n return object == null ? [] : baseFunctions(object, keysIn(object));\n }\n\n /**\n * Gets the value at `path` of `object`. If the resolved value is\n * `undefined`, the `defaultValue` is returned in its place.\n *\n * @static\n * @memberOf _\n * @since 3.7.0\n * @category Object\n * @param {Object} object The object to query.\n * @param {Array|string} path The path of the property to get.\n * @param {*} [defaultValue] The value returned for `undefined` resolved values.\n * @returns {*} Returns the resolved value.\n * @example\n *\n * var object = { 'a': [{ 'b': { 'c': 3 } }] };\n *\n * _.get(object, 'a[0].b.c');\n * // => 3\n *\n * _.get(object, ['a', '0', 'b', 'c']);\n * // => 3\n *\n * _.get(object, 'a.b.c', 'default');\n * // => 'default'\n */\n function get(object, path, defaultValue) {\n var result = object == null ? undefined : baseGet(object, path);\n return result === undefined ? defaultValue : result;\n }\n\n /**\n * Checks if `path` is a direct property of `object`.\n *\n * @static\n * @since 0.1.0\n * @memberOf _\n * @category Object\n * @param {Object} object The object to query.\n * @param {Array|string} path The path to check.\n * @returns {boolean} Returns `true` if `path` exists, else `false`.\n * @example\n *\n * var object = { 'a': { 'b': 2 } };\n * var other = _.create({ 'a': _.create({ 'b': 2 }) });\n *\n * _.has(object, 'a');\n * // => true\n *\n * _.has(object, 'a.b');\n * // => true\n *\n * _.has(object, ['a', 'b']);\n * // => true\n *\n * _.has(other, 'a');\n * // => false\n */\n function has(object, path) {\n return object != null && hasPath(object, path, baseHas);\n }\n\n /**\n * Checks if `path` is a direct or inherited property of `object`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Object\n * @param {Object} object The object to query.\n * @param {Array|string} path The path to check.\n * @returns {boolean} Returns `true` if `path` exists, else `false`.\n * @example\n *\n * var object = _.create({ 'a': _.create({ 'b': 2 }) });\n *\n * _.hasIn(object, 'a');\n * // => true\n *\n * _.hasIn(object, 'a.b');\n * // => true\n *\n * _.hasIn(object, ['a', 'b']);\n * // => true\n *\n * _.hasIn(object, 'b');\n * // => false\n */\n function hasIn(object, path) {\n return object != null && hasPath(object, path, baseHasIn);\n }\n\n /**\n * Creates an object composed of the inverted keys and values of `object`.\n * If `object` contains duplicate values, subsequent values overwrite\n * property assignments of previous values.\n *\n * @static\n * @memberOf _\n * @since 0.7.0\n * @category Object\n * @param {Object} object The object to invert.\n * @returns {Object} Returns the new inverted object.\n * @example\n *\n * var object = { 'a': 1, 'b': 2, 'c': 1 };\n *\n * _.invert(object);\n * // => { '1': 'c', '2': 'b' }\n */\n var invert = createInverter(function(result, value, key) {\n if (value != null &&\n typeof value.toString != 'function') {\n value = nativeObjectToString.call(value);\n }\n\n result[value] = key;\n }, constant(identity));\n\n /**\n * This method is like `_.invert` except that the inverted object is generated\n * from the results of running each element of `object` thru `iteratee`. The\n * corresponding inverted value of each inverted key is an array of keys\n * responsible for generating the inverted value. The iteratee is invoked\n * with one argument: (value).\n *\n * @static\n * @memberOf _\n * @since 4.1.0\n * @category Object\n * @param {Object} object The object to invert.\n * @param {Function} [iteratee=_.identity] The iteratee invoked per element.\n * @returns {Object} Returns the new inverted object.\n * @example\n *\n * var object = { 'a': 1, 'b': 2, 'c': 1 };\n *\n * _.invertBy(object);\n * // => { '1': ['a', 'c'], '2': ['b'] }\n *\n * _.invertBy(object, function(value) {\n * return 'group' + value;\n * });\n * // => { 'group1': ['a', 'c'], 'group2': ['b'] }\n */\n var invertBy = createInverter(function(result, value, key) {\n if (value != null &&\n typeof value.toString != 'function') {\n value = nativeObjectToString.call(value);\n }\n\n if (hasOwnProperty.call(result, value)) {\n result[value].push(key);\n } else {\n result[value] = [key];\n }\n }, getIteratee);\n\n /**\n * Invokes the method at `path` of `object`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Object\n * @param {Object} object The object to query.\n * @param {Array|string} path The path of the method to invoke.\n * @param {...*} [args] The arguments to invoke the method with.\n * @returns {*} Returns the result of the invoked method.\n * @example\n *\n * var object = { 'a': [{ 'b': { 'c': [1, 2, 3, 4] } }] };\n *\n * _.invoke(object, 'a[0].b.c.slice', 1, 3);\n * // => [2, 3]\n */\n var invoke = baseRest(baseInvoke);\n\n /**\n * Creates an array of the own enumerable property names of `object`.\n *\n * **Note:** Non-object values are coerced to objects. See the\n * [ES spec](http://ecma-international.org/ecma-262/7.0/#sec-object.keys)\n * for more details.\n *\n * @static\n * @since 0.1.0\n * @memberOf _\n * @category Object\n * @param {Object} object The object to query.\n * @returns {Array} Returns the array of property names.\n * @example\n *\n * function Foo() {\n * this.a = 1;\n * this.b = 2;\n * }\n *\n * Foo.prototype.c = 3;\n *\n * _.keys(new Foo);\n * // => ['a', 'b'] (iteration order is not guaranteed)\n *\n * _.keys('hi');\n * // => ['0', '1']\n */\n function keys(object) {\n return isArrayLike(object) ? arrayLikeKeys(object) : baseKeys(object);\n }\n\n /**\n * Creates an array of the own and inherited enumerable property names of `object`.\n *\n * **Note:** Non-object values are coerced to objects.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Object\n * @param {Object} object The object to query.\n * @returns {Array} Returns the array of property names.\n * @example\n *\n * function Foo() {\n * this.a = 1;\n * this.b = 2;\n * }\n *\n * Foo.prototype.c = 3;\n *\n * _.keysIn(new Foo);\n * // => ['a', 'b', 'c'] (iteration order is not guaranteed)\n */\n function keysIn(object) {\n return isArrayLike(object) ? arrayLikeKeys(object, true) : baseKeysIn(object);\n }\n\n /**\n * The opposite of `_.mapValues`; this method creates an object with the\n * same values as `object` and keys generated by running each own enumerable\n * string keyed property of `object` thru `iteratee`. The iteratee is invoked\n * with three arguments: (value, key, object).\n *\n * @static\n * @memberOf _\n * @since 3.8.0\n * @category Object\n * @param {Object} object The object to iterate over.\n * @param {Function} [iteratee=_.identity] The function invoked per iteration.\n * @returns {Object} Returns the new mapped object.\n * @see _.mapValues\n * @example\n *\n * _.mapKeys({ 'a': 1, 'b': 2 }, function(value, key) {\n * return key + value;\n * });\n * // => { 'a1': 1, 'b2': 2 }\n */\n function mapKeys(object, iteratee) {\n var result = {};\n iteratee = getIteratee(iteratee, 3);\n\n baseForOwn(object, function(value, key, object) {\n baseAssignValue(result, iteratee(value, key, object), value);\n });\n return result;\n }\n\n /**\n * Creates an object with the same keys as `object` and values generated\n * by running each own enumerable string keyed property of `object` thru\n * `iteratee`. The iteratee is invoked with three arguments:\n * (value, key, object).\n *\n * @static\n * @memberOf _\n * @since 2.4.0\n * @category Object\n * @param {Object} object The object to iterate over.\n * @param {Function} [iteratee=_.identity] The function invoked per iteration.\n * @returns {Object} Returns the new mapped object.\n * @see _.mapKeys\n * @example\n *\n * var users = {\n * 'fred': { 'user': 'fred', 'age': 40 },\n * 'pebbles': { 'user': 'pebbles', 'age': 1 }\n * };\n *\n * _.mapValues(users, function(o) { return o.age; });\n * // => { 'fred': 40, 'pebbles': 1 } (iteration order is not guaranteed)\n *\n * // The `_.property` iteratee shorthand.\n * _.mapValues(users, 'age');\n * // => { 'fred': 40, 'pebbles': 1 } (iteration order is not guaranteed)\n */\n function mapValues(object, iteratee) {\n var result = {};\n iteratee = getIteratee(iteratee, 3);\n\n baseForOwn(object, function(value, key, object) {\n baseAssignValue(result, key, iteratee(value, key, object));\n });\n return result;\n }\n\n /**\n * This method is like `_.assign` except that it recursively merges own and\n * inherited enumerable string keyed properties of source objects into the\n * destination object. Source properties that resolve to `undefined` are\n * skipped if a destination value exists. Array and plain object properties\n * are merged recursively. Other objects and value types are overridden by\n * assignment. Source objects are applied from left to right. Subsequent\n * sources overwrite property assignments of previous sources.\n *\n * **Note:** This method mutates `object`.\n *\n * @static\n * @memberOf _\n * @since 0.5.0\n * @category Object\n * @param {Object} object The destination object.\n * @param {...Object} [sources] The source objects.\n * @returns {Object} Returns `object`.\n * @example\n *\n * var object = {\n * 'a': [{ 'b': 2 }, { 'd': 4 }]\n * };\n *\n * var other = {\n * 'a': [{ 'c': 3 }, { 'e': 5 }]\n * };\n *\n * _.merge(object, other);\n * // => { 'a': [{ 'b': 2, 'c': 3 }, { 'd': 4, 'e': 5 }] }\n */\n var merge = createAssigner(function(object, source, srcIndex) {\n baseMerge(object, source, srcIndex);\n });\n\n /**\n * This method is like `_.merge` except that it accepts `customizer` which\n * is invoked to produce the merged values of the destination and source\n * properties. If `customizer` returns `undefined`, merging is handled by the\n * method instead. The `customizer` is invoked with six arguments:\n * (objValue, srcValue, key, object, source, stack).\n *\n * **Note:** This method mutates `object`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Object\n * @param {Object} object The destination object.\n * @param {...Object} sources The source objects.\n * @param {Function} customizer The function to customize assigned values.\n * @returns {Object} Returns `object`.\n * @example\n *\n * function customizer(objValue, srcValue) {\n * if (_.isArray(objValue)) {\n * return objValue.concat(srcValue);\n * }\n * }\n *\n * var object = { 'a': [1], 'b': [2] };\n * var other = { 'a': [3], 'b': [4] };\n *\n * _.mergeWith(object, other, customizer);\n * // => { 'a': [1, 3], 'b': [2, 4] }\n */\n var mergeWith = createAssigner(function(object, source, srcIndex, customizer) {\n baseMerge(object, source, srcIndex, customizer);\n });\n\n /**\n * The opposite of `_.pick`; this method creates an object composed of the\n * own and inherited enumerable property paths of `object` that are not omitted.\n *\n * **Note:** This method is considerably slower than `_.pick`.\n *\n * @static\n * @since 0.1.0\n * @memberOf _\n * @category Object\n * @param {Object} object The source object.\n * @param {...(string|string[])} [paths] The property paths to omit.\n * @returns {Object} Returns the new object.\n * @example\n *\n * var object = { 'a': 1, 'b': '2', 'c': 3 };\n *\n * _.omit(object, ['a', 'c']);\n * // => { 'b': '2' }\n */\n var omit = flatRest(function(object, paths) {\n var result = {};\n if (object == null) {\n return result;\n }\n var isDeep = false;\n paths = arrayMap(paths, function(path) {\n path = castPath(path, object);\n isDeep || (isDeep = path.length > 1);\n return path;\n });\n copyObject(object, getAllKeysIn(object), result);\n if (isDeep) {\n result = baseClone(result, CLONE_DEEP_FLAG | CLONE_FLAT_FLAG | CLONE_SYMBOLS_FLAG, customOmitClone);\n }\n var length = paths.length;\n while (length--) {\n baseUnset(result, paths[length]);\n }\n return result;\n });\n\n /**\n * The opposite of `_.pickBy`; this method creates an object composed of\n * the own and inherited enumerable string keyed properties of `object` that\n * `predicate` doesn't return truthy for. The predicate is invoked with two\n * arguments: (value, key).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Object\n * @param {Object} object The source object.\n * @param {Function} [predicate=_.identity] The function invoked per property.\n * @returns {Object} Returns the new object.\n * @example\n *\n * var object = { 'a': 1, 'b': '2', 'c': 3 };\n *\n * _.omitBy(object, _.isNumber);\n * // => { 'b': '2' }\n */\n function omitBy(object, predicate) {\n return pickBy(object, negate(getIteratee(predicate)));\n }\n\n /**\n * Creates an object composed of the picked `object` properties.\n *\n * @static\n * @since 0.1.0\n * @memberOf _\n * @category Object\n * @param {Object} object The source object.\n * @param {...(string|string[])} [paths] The property paths to pick.\n * @returns {Object} Returns the new object.\n * @example\n *\n * var object = { 'a': 1, 'b': '2', 'c': 3 };\n *\n * _.pick(object, ['a', 'c']);\n * // => { 'a': 1, 'c': 3 }\n */\n var pick = flatRest(function(object, paths) {\n return object == null ? {} : basePick(object, paths);\n });\n\n /**\n * Creates an object composed of the `object` properties `predicate` returns\n * truthy for. The predicate is invoked with two arguments: (value, key).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Object\n * @param {Object} object The source object.\n * @param {Function} [predicate=_.identity] The function invoked per property.\n * @returns {Object} Returns the new object.\n * @example\n *\n * var object = { 'a': 1, 'b': '2', 'c': 3 };\n *\n * _.pickBy(object, _.isNumber);\n * // => { 'a': 1, 'c': 3 }\n */\n function pickBy(object, predicate) {\n if (object == null) {\n return {};\n }\n var props = arrayMap(getAllKeysIn(object), function(prop) {\n return [prop];\n });\n predicate = getIteratee(predicate);\n return basePickBy(object, props, function(value, path) {\n return predicate(value, path[0]);\n });\n }\n\n /**\n * This method is like `_.get` except that if the resolved value is a\n * function it's invoked with the `this` binding of its parent object and\n * its result is returned.\n *\n * @static\n * @since 0.1.0\n * @memberOf _\n * @category Object\n * @param {Object} object The object to query.\n * @param {Array|string} path The path of the property to resolve.\n * @param {*} [defaultValue] The value returned for `undefined` resolved values.\n * @returns {*} Returns the resolved value.\n * @example\n *\n * var object = { 'a': [{ 'b': { 'c1': 3, 'c2': _.constant(4) } }] };\n *\n * _.result(object, 'a[0].b.c1');\n * // => 3\n *\n * _.result(object, 'a[0].b.c2');\n * // => 4\n *\n * _.result(object, 'a[0].b.c3', 'default');\n * // => 'default'\n *\n * _.result(object, 'a[0].b.c3', _.constant('default'));\n * // => 'default'\n */\n function result(object, path, defaultValue) {\n path = castPath(path, object);\n\n var index = -1,\n length = path.length;\n\n // Ensure the loop is entered when path is empty.\n if (!length) {\n length = 1;\n object = undefined;\n }\n while (++index < length) {\n var value = object == null ? undefined : object[toKey(path[index])];\n if (value === undefined) {\n index = length;\n value = defaultValue;\n }\n object = isFunction(value) ? value.call(object) : value;\n }\n return object;\n }\n\n /**\n * Sets the value at `path` of `object`. If a portion of `path` doesn't exist,\n * it's created. Arrays are created for missing index properties while objects\n * are created for all other missing properties. Use `_.setWith` to customize\n * `path` creation.\n *\n * **Note:** This method mutates `object`.\n *\n * @static\n * @memberOf _\n * @since 3.7.0\n * @category Object\n * @param {Object} object The object to modify.\n * @param {Array|string} path The path of the property to set.\n * @param {*} value The value to set.\n * @returns {Object} Returns `object`.\n * @example\n *\n * var object = { 'a': [{ 'b': { 'c': 3 } }] };\n *\n * _.set(object, 'a[0].b.c', 4);\n * console.log(object.a[0].b.c);\n * // => 4\n *\n * _.set(object, ['x', '0', 'y', 'z'], 5);\n * console.log(object.x[0].y.z);\n * // => 5\n */\n function set(object, path, value) {\n return object == null ? object : baseSet(object, path, value);\n }\n\n /**\n * This method is like `_.set` except that it accepts `customizer` which is\n * invoked to produce the objects of `path`. If `customizer` returns `undefined`\n * path creation is handled by the method instead. The `customizer` is invoked\n * with three arguments: (nsValue, key, nsObject).\n *\n * **Note:** This method mutates `object`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Object\n * @param {Object} object The object to modify.\n * @param {Array|string} path The path of the property to set.\n * @param {*} value The value to set.\n * @param {Function} [customizer] The function to customize assigned values.\n * @returns {Object} Returns `object`.\n * @example\n *\n * var object = {};\n *\n * _.setWith(object, '[0][1]', 'a', Object);\n * // => { '0': { '1': 'a' } }\n */\n function setWith(object, path, value, customizer) {\n customizer = typeof customizer == 'function' ? customizer : undefined;\n return object == null ? object : baseSet(object, path, value, customizer);\n }\n\n /**\n * Creates an array of own enumerable string keyed-value pairs for `object`\n * which can be consumed by `_.fromPairs`. If `object` is a map or set, its\n * entries are returned.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @alias entries\n * @category Object\n * @param {Object} object The object to query.\n * @returns {Array} Returns the key-value pairs.\n * @example\n *\n * function Foo() {\n * this.a = 1;\n * this.b = 2;\n * }\n *\n * Foo.prototype.c = 3;\n *\n * _.toPairs(new Foo);\n * // => [['a', 1], ['b', 2]] (iteration order is not guaranteed)\n */\n var toPairs = createToPairs(keys);\n\n /**\n * Creates an array of own and inherited enumerable string keyed-value pairs\n * for `object` which can be consumed by `_.fromPairs`. If `object` is a map\n * or set, its entries are returned.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @alias entriesIn\n * @category Object\n * @param {Object} object The object to query.\n * @returns {Array} Returns the key-value pairs.\n * @example\n *\n * function Foo() {\n * this.a = 1;\n * this.b = 2;\n * }\n *\n * Foo.prototype.c = 3;\n *\n * _.toPairsIn(new Foo);\n * // => [['a', 1], ['b', 2], ['c', 3]] (iteration order is not guaranteed)\n */\n var toPairsIn = createToPairs(keysIn);\n\n /**\n * An alternative to `_.reduce`; this method transforms `object` to a new\n * `accumulator` object which is the result of running each of its own\n * enumerable string keyed properties thru `iteratee`, with each invocation\n * potentially mutating the `accumulator` object. If `accumulator` is not\n * provided, a new object with the same `[[Prototype]]` will be used. The\n * iteratee is invoked with four arguments: (accumulator, value, key, object).\n * Iteratee functions may exit iteration early by explicitly returning `false`.\n *\n * @static\n * @memberOf _\n * @since 1.3.0\n * @category Object\n * @param {Object} object The object to iterate over.\n * @param {Function} [iteratee=_.identity] The function invoked per iteration.\n * @param {*} [accumulator] The custom accumulator value.\n * @returns {*} Returns the accumulated value.\n * @example\n *\n * _.transform([2, 3, 4], function(result, n) {\n * result.push(n *= n);\n * return n % 2 == 0;\n * }, []);\n * // => [4, 9]\n *\n * _.transform({ 'a': 1, 'b': 2, 'c': 1 }, function(result, value, key) {\n * (result[value] || (result[value] = [])).push(key);\n * }, {});\n * // => { '1': ['a', 'c'], '2': ['b'] }\n */\n function transform(object, iteratee, accumulator) {\n var isArr = isArray(object),\n isArrLike = isArr || isBuffer(object) || isTypedArray(object);\n\n iteratee = getIteratee(iteratee, 4);\n if (accumulator == null) {\n var Ctor = object && object.constructor;\n if (isArrLike) {\n accumulator = isArr ? new Ctor : [];\n }\n else if (isObject(object)) {\n accumulator = isFunction(Ctor) ? baseCreate(getPrototype(object)) : {};\n }\n else {\n accumulator = {};\n }\n }\n (isArrLike ? arrayEach : baseForOwn)(object, function(value, index, object) {\n return iteratee(accumulator, value, index, object);\n });\n return accumulator;\n }\n\n /**\n * Removes the property at `path` of `object`.\n *\n * **Note:** This method mutates `object`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Object\n * @param {Object} object The object to modify.\n * @param {Array|string} path The path of the property to unset.\n * @returns {boolean} Returns `true` if the property is deleted, else `false`.\n * @example\n *\n * var object = { 'a': [{ 'b': { 'c': 7 } }] };\n * _.unset(object, 'a[0].b.c');\n * // => true\n *\n * console.log(object);\n * // => { 'a': [{ 'b': {} }] };\n *\n * _.unset(object, ['a', '0', 'b', 'c']);\n * // => true\n *\n * console.log(object);\n * // => { 'a': [{ 'b': {} }] };\n */\n function unset(object, path) {\n return object == null ? true : baseUnset(object, path);\n }\n\n /**\n * This method is like `_.set` except that accepts `updater` to produce the\n * value to set. Use `_.updateWith` to customize `path` creation. The `updater`\n * is invoked with one argument: (value).\n *\n * **Note:** This method mutates `object`.\n *\n * @static\n * @memberOf _\n * @since 4.6.0\n * @category Object\n * @param {Object} object The object to modify.\n * @param {Array|string} path The path of the property to set.\n * @param {Function} updater The function to produce the updated value.\n * @returns {Object} Returns `object`.\n * @example\n *\n * var object = { 'a': [{ 'b': { 'c': 3 } }] };\n *\n * _.update(object, 'a[0].b.c', function(n) { return n * n; });\n * console.log(object.a[0].b.c);\n * // => 9\n *\n * _.update(object, 'x[0].y.z', function(n) { return n ? n + 1 : 0; });\n * console.log(object.x[0].y.z);\n * // => 0\n */\n function update(object, path, updater) {\n return object == null ? object : baseUpdate(object, path, castFunction(updater));\n }\n\n /**\n * This method is like `_.update` except that it accepts `customizer` which is\n * invoked to produce the objects of `path`. If `customizer` returns `undefined`\n * path creation is handled by the method instead. The `customizer` is invoked\n * with three arguments: (nsValue, key, nsObject).\n *\n * **Note:** This method mutates `object`.\n *\n * @static\n * @memberOf _\n * @since 4.6.0\n * @category Object\n * @param {Object} object The object to modify.\n * @param {Array|string} path The path of the property to set.\n * @param {Function} updater The function to produce the updated value.\n * @param {Function} [customizer] The function to customize assigned values.\n * @returns {Object} Returns `object`.\n * @example\n *\n * var object = {};\n *\n * _.updateWith(object, '[0][1]', _.constant('a'), Object);\n * // => { '0': { '1': 'a' } }\n */\n function updateWith(object, path, updater, customizer) {\n customizer = typeof customizer == 'function' ? customizer : undefined;\n return object == null ? object : baseUpdate(object, path, castFunction(updater), customizer);\n }\n\n /**\n * Creates an array of the own enumerable string keyed property values of `object`.\n *\n * **Note:** Non-object values are coerced to objects.\n *\n * @static\n * @since 0.1.0\n * @memberOf _\n * @category Object\n * @param {Object} object The object to query.\n * @returns {Array} Returns the array of property values.\n * @example\n *\n * function Foo() {\n * this.a = 1;\n * this.b = 2;\n * }\n *\n * Foo.prototype.c = 3;\n *\n * _.values(new Foo);\n * // => [1, 2] (iteration order is not guaranteed)\n *\n * _.values('hi');\n * // => ['h', 'i']\n */\n function values(object) {\n return object == null ? [] : baseValues(object, keys(object));\n }\n\n /**\n * Creates an array of the own and inherited enumerable string keyed property\n * values of `object`.\n *\n * **Note:** Non-object values are coerced to objects.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category Object\n * @param {Object} object The object to query.\n * @returns {Array} Returns the array of property values.\n * @example\n *\n * function Foo() {\n * this.a = 1;\n * this.b = 2;\n * }\n *\n * Foo.prototype.c = 3;\n *\n * _.valuesIn(new Foo);\n * // => [1, 2, 3] (iteration order is not guaranteed)\n */\n function valuesIn(object) {\n return object == null ? [] : baseValues(object, keysIn(object));\n }\n\n /*------------------------------------------------------------------------*/\n\n /**\n * Clamps `number` within the inclusive `lower` and `upper` bounds.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category Number\n * @param {number} number The number to clamp.\n * @param {number} [lower] The lower bound.\n * @param {number} upper The upper bound.\n * @returns {number} Returns the clamped number.\n * @example\n *\n * _.clamp(-10, -5, 5);\n * // => -5\n *\n * _.clamp(10, -5, 5);\n * // => 5\n */\n function clamp(number, lower, upper) {\n if (upper === undefined) {\n upper = lower;\n lower = undefined;\n }\n if (upper !== undefined) {\n upper = toNumber(upper);\n upper = upper === upper ? upper : 0;\n }\n if (lower !== undefined) {\n lower = toNumber(lower);\n lower = lower === lower ? lower : 0;\n }\n return baseClamp(toNumber(number), lower, upper);\n }\n\n /**\n * Checks if `n` is between `start` and up to, but not including, `end`. If\n * `end` is not specified, it's set to `start` with `start` then set to `0`.\n * If `start` is greater than `end` the params are swapped to support\n * negative ranges.\n *\n * @static\n * @memberOf _\n * @since 3.3.0\n * @category Number\n * @param {number} number The number to check.\n * @param {number} [start=0] The start of the range.\n * @param {number} end The end of the range.\n * @returns {boolean} Returns `true` if `number` is in the range, else `false`.\n * @see _.range, _.rangeRight\n * @example\n *\n * _.inRange(3, 2, 4);\n * // => true\n *\n * _.inRange(4, 8);\n * // => true\n *\n * _.inRange(4, 2);\n * // => false\n *\n * _.inRange(2, 2);\n * // => false\n *\n * _.inRange(1.2, 2);\n * // => true\n *\n * _.inRange(5.2, 4);\n * // => false\n *\n * _.inRange(-3, -2, -6);\n * // => true\n */\n function inRange(number, start, end) {\n start = toFinite(start);\n if (end === undefined) {\n end = start;\n start = 0;\n } else {\n end = toFinite(end);\n }\n number = toNumber(number);\n return baseInRange(number, start, end);\n }\n\n /**\n * Produces a random number between the inclusive `lower` and `upper` bounds.\n * If only one argument is provided a number between `0` and the given number\n * is returned. If `floating` is `true`, or either `lower` or `upper` are\n * floats, a floating-point number is returned instead of an integer.\n *\n * **Note:** JavaScript follows the IEEE-754 standard for resolving\n * floating-point values which can produce unexpected results.\n *\n * @static\n * @memberOf _\n * @since 0.7.0\n * @category Number\n * @param {number} [lower=0] The lower bound.\n * @param {number} [upper=1] The upper bound.\n * @param {boolean} [floating] Specify returning a floating-point number.\n * @returns {number} Returns the random number.\n * @example\n *\n * _.random(0, 5);\n * // => an integer between 0 and 5\n *\n * _.random(5);\n * // => also an integer between 0 and 5\n *\n * _.random(5, true);\n * // => a floating-point number between 0 and 5\n *\n * _.random(1.2, 5.2);\n * // => a floating-point number between 1.2 and 5.2\n */\n function random(lower, upper, floating) {\n if (floating && typeof floating != 'boolean' && isIterateeCall(lower, upper, floating)) {\n upper = floating = undefined;\n }\n if (floating === undefined) {\n if (typeof upper == 'boolean') {\n floating = upper;\n upper = undefined;\n }\n else if (typeof lower == 'boolean') {\n floating = lower;\n lower = undefined;\n }\n }\n if (lower === undefined && upper === undefined) {\n lower = 0;\n upper = 1;\n }\n else {\n lower = toFinite(lower);\n if (upper === undefined) {\n upper = lower;\n lower = 0;\n } else {\n upper = toFinite(upper);\n }\n }\n if (lower > upper) {\n var temp = lower;\n lower = upper;\n upper = temp;\n }\n if (floating || lower % 1 || upper % 1) {\n var rand = nativeRandom();\n return nativeMin(lower + (rand * (upper - lower + freeParseFloat('1e-' + ((rand + '').length - 1)))), upper);\n }\n return baseRandom(lower, upper);\n }\n\n /*------------------------------------------------------------------------*/\n\n /**\n * Converts `string` to [camel case](https://en.wikipedia.org/wiki/CamelCase).\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category String\n * @param {string} [string=''] The string to convert.\n * @returns {string} Returns the camel cased string.\n * @example\n *\n * _.camelCase('Foo Bar');\n * // => 'fooBar'\n *\n * _.camelCase('--foo-bar--');\n * // => 'fooBar'\n *\n * _.camelCase('__FOO_BAR__');\n * // => 'fooBar'\n */\n var camelCase = createCompounder(function(result, word, index) {\n word = word.toLowerCase();\n return result + (index ? capitalize(word) : word);\n });\n\n /**\n * Converts the first character of `string` to upper case and the remaining\n * to lower case.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category String\n * @param {string} [string=''] The string to capitalize.\n * @returns {string} Returns the capitalized string.\n * @example\n *\n * _.capitalize('FRED');\n * // => 'Fred'\n */\n function capitalize(string) {\n return upperFirst(toString(string).toLowerCase());\n }\n\n /**\n * Deburrs `string` by converting\n * [Latin-1 Supplement](https://en.wikipedia.org/wiki/Latin-1_Supplement_(Unicode_block)#Character_table)\n * and [Latin Extended-A](https://en.wikipedia.org/wiki/Latin_Extended-A)\n * letters to basic Latin letters and removing\n * [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks).\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category String\n * @param {string} [string=''] The string to deburr.\n * @returns {string} Returns the deburred string.\n * @example\n *\n * _.deburr('déjà vu');\n * // => 'deja vu'\n */\n function deburr(string) {\n string = toString(string);\n return string && string.replace(reLatin, deburrLetter).replace(reComboMark, '');\n }\n\n /**\n * Checks if `string` ends with the given target string.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category String\n * @param {string} [string=''] The string to inspect.\n * @param {string} [target] The string to search for.\n * @param {number} [position=string.length] The position to search up to.\n * @returns {boolean} Returns `true` if `string` ends with `target`,\n * else `false`.\n * @example\n *\n * _.endsWith('abc', 'c');\n * // => true\n *\n * _.endsWith('abc', 'b');\n * // => false\n *\n * _.endsWith('abc', 'b', 2);\n * // => true\n */\n function endsWith(string, target, position) {\n string = toString(string);\n target = baseToString(target);\n\n var length = string.length;\n position = position === undefined\n ? length\n : baseClamp(toInteger(position), 0, length);\n\n var end = position;\n position -= target.length;\n return position >= 0 && string.slice(position, end) == target;\n }\n\n /**\n * Converts the characters \"&\", \"<\", \">\", '\"', and \"'\" in `string` to their\n * corresponding HTML entities.\n *\n * **Note:** No other characters are escaped. To escape additional\n * characters use a third-party library like [_he_](https://mths.be/he).\n *\n * Though the \">\" character is escaped for symmetry, characters like\n * \">\" and \"/\" don't need escaping in HTML and have no special meaning\n * unless they're part of a tag or unquoted attribute value. See\n * [Mathias Bynens's article](https://mathiasbynens.be/notes/ambiguous-ampersands)\n * (under \"semi-related fun fact\") for more details.\n *\n * When working with HTML you should always\n * [quote attribute values](http://wonko.com/post/html-escaping) to reduce\n * XSS vectors.\n *\n * @static\n * @since 0.1.0\n * @memberOf _\n * @category String\n * @param {string} [string=''] The string to escape.\n * @returns {string} Returns the escaped string.\n * @example\n *\n * _.escape('fred, barney, & pebbles');\n * // => 'fred, barney, & pebbles'\n */\n function escape(string) {\n string = toString(string);\n return (string && reHasUnescapedHtml.test(string))\n ? string.replace(reUnescapedHtml, escapeHtmlChar)\n : string;\n }\n\n /**\n * Escapes the `RegExp` special characters \"^\", \"$\", \"\\\", \".\", \"*\", \"+\",\n * \"?\", \"(\", \")\", \"[\", \"]\", \"{\", \"}\", and \"|\" in `string`.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category String\n * @param {string} [string=''] The string to escape.\n * @returns {string} Returns the escaped string.\n * @example\n *\n * _.escapeRegExp('[lodash](https://lodash.com/)');\n * // => '\\[lodash\\]\\(https://lodash\\.com/\\)'\n */\n function escapeRegExp(string) {\n string = toString(string);\n return (string && reHasRegExpChar.test(string))\n ? string.replace(reRegExpChar, '\\\\$&')\n : string;\n }\n\n /**\n * Converts `string` to\n * [kebab case](https://en.wikipedia.org/wiki/Letter_case#Special_case_styles).\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category String\n * @param {string} [string=''] The string to convert.\n * @returns {string} Returns the kebab cased string.\n * @example\n *\n * _.kebabCase('Foo Bar');\n * // => 'foo-bar'\n *\n * _.kebabCase('fooBar');\n * // => 'foo-bar'\n *\n * _.kebabCase('__FOO_BAR__');\n * // => 'foo-bar'\n */\n var kebabCase = createCompounder(function(result, word, index) {\n return result + (index ? '-' : '') + word.toLowerCase();\n });\n\n /**\n * Converts `string`, as space separated words, to lower case.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category String\n * @param {string} [string=''] The string to convert.\n * @returns {string} Returns the lower cased string.\n * @example\n *\n * _.lowerCase('--Foo-Bar--');\n * // => 'foo bar'\n *\n * _.lowerCase('fooBar');\n * // => 'foo bar'\n *\n * _.lowerCase('__FOO_BAR__');\n * // => 'foo bar'\n */\n var lowerCase = createCompounder(function(result, word, index) {\n return result + (index ? ' ' : '') + word.toLowerCase();\n });\n\n /**\n * Converts the first character of `string` to lower case.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category String\n * @param {string} [string=''] The string to convert.\n * @returns {string} Returns the converted string.\n * @example\n *\n * _.lowerFirst('Fred');\n * // => 'fred'\n *\n * _.lowerFirst('FRED');\n * // => 'fRED'\n */\n var lowerFirst = createCaseFirst('toLowerCase');\n\n /**\n * Pads `string` on the left and right sides if it's shorter than `length`.\n * Padding characters are truncated if they can't be evenly divided by `length`.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category String\n * @param {string} [string=''] The string to pad.\n * @param {number} [length=0] The padding length.\n * @param {string} [chars=' '] The string used as padding.\n * @returns {string} Returns the padded string.\n * @example\n *\n * _.pad('abc', 8);\n * // => ' abc '\n *\n * _.pad('abc', 8, '_-');\n * // => '_-abc_-_'\n *\n * _.pad('abc', 3);\n * // => 'abc'\n */\n function pad(string, length, chars) {\n string = toString(string);\n length = toInteger(length);\n\n var strLength = length ? stringSize(string) : 0;\n if (!length || strLength >= length) {\n return string;\n }\n var mid = (length - strLength) / 2;\n return (\n createPadding(nativeFloor(mid), chars) +\n string +\n createPadding(nativeCeil(mid), chars)\n );\n }\n\n /**\n * Pads `string` on the right side if it's shorter than `length`. Padding\n * characters are truncated if they exceed `length`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category String\n * @param {string} [string=''] The string to pad.\n * @param {number} [length=0] The padding length.\n * @param {string} [chars=' '] The string used as padding.\n * @returns {string} Returns the padded string.\n * @example\n *\n * _.padEnd('abc', 6);\n * // => 'abc '\n *\n * _.padEnd('abc', 6, '_-');\n * // => 'abc_-_'\n *\n * _.padEnd('abc', 3);\n * // => 'abc'\n */\n function padEnd(string, length, chars) {\n string = toString(string);\n length = toInteger(length);\n\n var strLength = length ? stringSize(string) : 0;\n return (length && strLength < length)\n ? (string + createPadding(length - strLength, chars))\n : string;\n }\n\n /**\n * Pads `string` on the left side if it's shorter than `length`. Padding\n * characters are truncated if they exceed `length`.\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category String\n * @param {string} [string=''] The string to pad.\n * @param {number} [length=0] The padding length.\n * @param {string} [chars=' '] The string used as padding.\n * @returns {string} Returns the padded string.\n * @example\n *\n * _.padStart('abc', 6);\n * // => ' abc'\n *\n * _.padStart('abc', 6, '_-');\n * // => '_-_abc'\n *\n * _.padStart('abc', 3);\n * // => 'abc'\n */\n function padStart(string, length, chars) {\n string = toString(string);\n length = toInteger(length);\n\n var strLength = length ? stringSize(string) : 0;\n return (length && strLength < length)\n ? (createPadding(length - strLength, chars) + string)\n : string;\n }\n\n /**\n * Converts `string` to an integer of the specified radix. If `radix` is\n * `undefined` or `0`, a `radix` of `10` is used unless `value` is a\n * hexadecimal, in which case a `radix` of `16` is used.\n *\n * **Note:** This method aligns with the\n * [ES5 implementation](https://es5.github.io/#x15.1.2.2) of `parseInt`.\n *\n * @static\n * @memberOf _\n * @since 1.1.0\n * @category String\n * @param {string} string The string to convert.\n * @param {number} [radix=10] The radix to interpret `value` by.\n * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.\n * @returns {number} Returns the converted integer.\n * @example\n *\n * _.parseInt('08');\n * // => 8\n *\n * _.map(['6', '08', '10'], _.parseInt);\n * // => [6, 8, 10]\n */\n function parseInt(string, radix, guard) {\n if (guard || radix == null) {\n radix = 0;\n } else if (radix) {\n radix = +radix;\n }\n return nativeParseInt(toString(string).replace(reTrimStart, ''), radix || 0);\n }\n\n /**\n * Repeats the given string `n` times.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category String\n * @param {string} [string=''] The string to repeat.\n * @param {number} [n=1] The number of times to repeat the string.\n * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.\n * @returns {string} Returns the repeated string.\n * @example\n *\n * _.repeat('*', 3);\n * // => '***'\n *\n * _.repeat('abc', 2);\n * // => 'abcabc'\n *\n * _.repeat('abc', 0);\n * // => ''\n */\n function repeat(string, n, guard) {\n if ((guard ? isIterateeCall(string, n, guard) : n === undefined)) {\n n = 1;\n } else {\n n = toInteger(n);\n }\n return baseRepeat(toString(string), n);\n }\n\n /**\n * Replaces matches for `pattern` in `string` with `replacement`.\n *\n * **Note:** This method is based on\n * [`String#replace`](https://mdn.io/String/replace).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category String\n * @param {string} [string=''] The string to modify.\n * @param {RegExp|string} pattern The pattern to replace.\n * @param {Function|string} replacement The match replacement.\n * @returns {string} Returns the modified string.\n * @example\n *\n * _.replace('Hi Fred', 'Fred', 'Barney');\n * // => 'Hi Barney'\n */\n function replace() {\n var args = arguments,\n string = toString(args[0]);\n\n return args.length < 3 ? string : string.replace(args[1], args[2]);\n }\n\n /**\n * Converts `string` to\n * [snake case](https://en.wikipedia.org/wiki/Snake_case).\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category String\n * @param {string} [string=''] The string to convert.\n * @returns {string} Returns the snake cased string.\n * @example\n *\n * _.snakeCase('Foo Bar');\n * // => 'foo_bar'\n *\n * _.snakeCase('fooBar');\n * // => 'foo_bar'\n *\n * _.snakeCase('--FOO-BAR--');\n * // => 'foo_bar'\n */\n var snakeCase = createCompounder(function(result, word, index) {\n return result + (index ? '_' : '') + word.toLowerCase();\n });\n\n /**\n * Splits `string` by `separator`.\n *\n * **Note:** This method is based on\n * [`String#split`](https://mdn.io/String/split).\n *\n * @static\n * @memberOf _\n * @since 4.0.0\n * @category String\n * @param {string} [string=''] The string to split.\n * @param {RegExp|string} separator The separator pattern to split by.\n * @param {number} [limit] The length to truncate results to.\n * @returns {Array} Returns the string segments.\n * @example\n *\n * _.split('a-b-c', '-', 2);\n * // => ['a', 'b']\n */\n function split(string, separator, limit) {\n if (limit && typeof limit != 'number' && isIterateeCall(string, separator, limit)) {\n separator = limit = undefined;\n }\n limit = limit === undefined ? MAX_ARRAY_LENGTH : limit >>> 0;\n if (!limit) {\n return [];\n }\n string = toString(string);\n if (string && (\n typeof separator == 'string' ||\n (separator != null && !isRegExp(separator))\n )) {\n separator = baseToString(separator);\n if (!separator && hasUnicode(string)) {\n return castSlice(stringToArray(string), 0, limit);\n }\n }\n return string.split(separator, limit);\n }\n\n /**\n * Converts `string` to\n * [start case](https://en.wikipedia.org/wiki/Letter_case#Stylistic_or_specialised_usage).\n *\n * @static\n * @memberOf _\n * @since 3.1.0\n * @category String\n * @param {string} [string=''] The string to convert.\n * @returns {string} Returns the start cased string.\n * @example\n *\n * _.startCase('--foo-bar--');\n * // => 'Foo Bar'\n *\n * _.startCase('fooBar');\n * // => 'Foo Bar'\n *\n * _.startCase('__FOO_BAR__');\n * // => 'FOO BAR'\n */\n var startCase = createCompounder(function(result, word, index) {\n return result + (index ? ' ' : '') + upperFirst(word);\n });\n\n /**\n * Checks if `string` starts with the given target string.\n *\n * @static\n * @memberOf _\n * @since 3.0.0\n * @category String\n * @param {string} [string=''] The string to inspect.\n * @param {string} [target] The string to search for.\n * @param {number} [position=0] The position to search from.\n * @returns {boolean} Returns `true` if `string` starts with `target`,\n * else `false`.\n * @example\n *\n * _.startsWith('abc', 'a');\n * // => true\n *\n * _.startsWith('abc', 'b');\n * // => false\n *\n * _.startsWith('abc', 'b', 1);\n * // => true\n */\n function startsWith(string, target, position) {\n string = toString(string);\n position = position == null\n ? 0\n : baseClamp(toInteger(position), 0, string.length);\n\n target = baseToString(target);\n return string.slice(position, position + target.length) == target;\n }\n\n /**\n * Creates a compiled template function that can interpolate data properties\n * in \"interpolate\" delimiters, HTML-escape interpolated data properties in\n * \"escape\" delimiters, and execute JavaScript in \"evaluate\" delimiters. Data\n * properties may be accessed as free variables in the template. If a setting\n * object is given, it takes precedence over `_.templateSettings` values.\n *\n * **Note:** In the development build `_.template` utilizes\n * [sourceURLs](http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl)\n * for easier debugging.\n *\n * For more information on precompiling templates see\n * [lodash's custom builds documentation](https://lodash.com/custom-builds).\n *\n * For more information on Chrome extension sandboxes see\n * [Chrome's extensions documentation](https://developer.chrome.com/extensions/sandboxingEval).\n *\n * @static\n * @since 0.1.0\n * @memberOf _\n * @category String\n * @param {string} [string=''] The template string.\n * @param {Object} [options={}] The options object.\n * @param {RegExp} [options.escape=_.templateSettings.escape]\n * The HTML \"escape\" delimiter.\n * @param {RegExp} [options.evaluate=_.templateSettings.evaluate]\n * The \"evaluate\" delimiter.\n * @param {Object} [options.imports=_.templateSettings.imports]\n * An object to import into the template as free variables.\n * @param {RegExp} [options.interpolate=_.templateSettings.interpolate]\n * The \"interpolate\" delimiter.\n * @param {string} [options.sourceURL='lodash.templateSources[n]']\n * The sourceURL of the compiled template.\n * @param {string} [options.variable='obj']\n * The data object variable name.\n * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`.\n * @returns {Function} Returns the compiled template function.\n * @example\n *\n * // Use the \"interpolate\" delimiter to create a compiled template.\n * var compiled = _.template('hello <%= user %>!');\n * compiled({ 'user': 'fred' });\n * // => 'hello fred!'\n *\n * // Use the HTML \"escape\" delimiter to escape data property values.\n * var compiled = _.template('<%- value %>');\n * compiled({ 'value': '';\n }\n const iframeContents = '' + script + '';\n try {\n this.myIFrame.doc.open();\n this.myIFrame.doc.write(iframeContents);\n this.myIFrame.doc.close();\n } catch (e) {\n log('frame writing exception');\n if (e.stack) {\n log(e.stack);\n }\n log(e);\n }\n } else {\n this.commandCB = commandCB;\n this.onMessageCB = onMessageCB;\n }\n }\n\n /**\n * Each browser has its own funny way to handle iframes. Here we mush them all together into one object that I can\n * actually use.\n * @private\n * @return {Element}\n */\n private static createIFrame_(): IFrameElement {\n const iframe = document.createElement('iframe') as IFrameElement;\n iframe.style.display = 'none';\n\n // This is necessary in order to initialize the document inside the iframe\n if (document.body) {\n document.body.appendChild(iframe);\n try {\n // If document.domain has been modified in IE, this will throw an error, and we need to set the\n // domain of the iframe's document manually. We can do this via a javascript: url as the src attribute\n // Also note that we must do this *after* the iframe has been appended to the page. Otherwise it doesn't work.\n const a = iframe.contentWindow.document;\n if (!a) {\n // Apologies for the log-spam, I need to do something to keep closure from optimizing out the assignment above.\n log('No IE domain setting required');\n }\n } catch (e) {\n const domain = document.domain;\n iframe.src =\n \"javascript:void((function(){document.open();document.domain='\" +\n domain +\n \"';document.close();})())\";\n }\n } else {\n // LongPollConnection attempts to delay initialization until the document is ready, so hopefully this\n // never gets hit.\n throw 'Document body has not initialized. Wait to initialize Firebase until after the document is ready.';\n }\n\n // Get the document of the iframe in a browser-specific way.\n if (iframe.contentDocument) {\n iframe.doc = iframe.contentDocument; // Firefox, Opera, Safari\n } else if (iframe.contentWindow) {\n iframe.doc = iframe.contentWindow.document; // Internet Explorer\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n } else if ((iframe as any).document) {\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n iframe.doc = (iframe as any).document; //others?\n }\n\n return iframe;\n }\n\n /**\n * Cancel all outstanding queries and remove the frame.\n */\n close() {\n //Mark this iframe as dead, so no new requests are sent.\n this.alive = false;\n\n if (this.myIFrame) {\n //We have to actually remove all of the html inside this iframe before removing it from the\n //window, or IE will continue loading and executing the script tags we've already added, which\n //can lead to some errors being thrown. Setting innerHTML seems to be the easiest way to do this.\n this.myIFrame.doc.body.innerHTML = '';\n setTimeout(() => {\n if (this.myIFrame !== null) {\n document.body.removeChild(this.myIFrame);\n this.myIFrame = null;\n }\n }, Math.floor(0));\n }\n\n // Protect from being called recursively.\n const onDisconnect = this.onDisconnect;\n if (onDisconnect) {\n this.onDisconnect = null;\n onDisconnect();\n }\n }\n\n /**\n * Actually start the long-polling session by adding the first script tag(s) to the iframe.\n * @param {!string} id - The ID of this connection\n * @param {!string} pw - The password for this connection\n */\n startLongPoll(id: string, pw: string) {\n this.myID = id;\n this.myPW = pw;\n this.alive = true;\n\n //send the initial request. If there are requests queued, make sure that we transmit as many as we are currently able to.\n while (this.newRequest_()) {}\n }\n\n /**\n * This is called any time someone might want a script tag to be added. It adds a script tag when there aren't\n * too many outstanding requests and we are still alive.\n *\n * If there are outstanding packet segments to send, it sends one. If there aren't, it sends a long-poll anyways if\n * needed.\n */\n private newRequest_() {\n // We keep one outstanding request open all the time to receive data, but if we need to send data\n // (pendingSegs.length > 0) then we create a new request to send the data. The server will automatically\n // close the old request.\n if (\n this.alive &&\n this.sendNewPolls &&\n this.outstandingRequests.size < (this.pendingSegs.length > 0 ? 2 : 1)\n ) {\n //construct our url\n this.currentSerial++;\n const urlParams: { [k: string]: string | number } = {};\n urlParams[FIREBASE_LONGPOLL_ID_PARAM] = this.myID;\n urlParams[FIREBASE_LONGPOLL_PW_PARAM] = this.myPW;\n urlParams[FIREBASE_LONGPOLL_SERIAL_PARAM] = this.currentSerial;\n let theURL = this.urlFn(urlParams);\n //Now add as much data as we can.\n let curDataString = '';\n let i = 0;\n\n while (this.pendingSegs.length > 0) {\n //first, lets see if the next segment will fit.\n const nextSeg = this.pendingSegs[0];\n if (\n (nextSeg.d as unknown[]).length +\n SEG_HEADER_SIZE +\n curDataString.length <=\n MAX_URL_DATA_SIZE\n ) {\n //great, the segment will fit. Lets append it.\n const theSeg = this.pendingSegs.shift();\n curDataString =\n curDataString +\n '&' +\n FIREBASE_LONGPOLL_SEGMENT_NUM_PARAM +\n i +\n '=' +\n theSeg.seg +\n '&' +\n FIREBASE_LONGPOLL_SEGMENTS_IN_PACKET +\n i +\n '=' +\n theSeg.ts +\n '&' +\n FIREBASE_LONGPOLL_DATA_PARAM +\n i +\n '=' +\n theSeg.d;\n i++;\n } else {\n break;\n }\n }\n\n theURL = theURL + curDataString;\n this.addLongPollTag_(theURL, this.currentSerial);\n\n return true;\n } else {\n return false;\n }\n }\n\n /**\n * Queue a packet for transmission to the server.\n * @param segnum - A sequential id for this packet segment used for reassembly\n * @param totalsegs - The total number of segments in this packet\n * @param data - The data for this segment.\n */\n enqueueSegment(segnum: number, totalsegs: number, data: unknown) {\n //add this to the queue of segments to send.\n this.pendingSegs.push({ seg: segnum, ts: totalsegs, d: data });\n\n //send the data immediately if there isn't already data being transmitted, unless\n //startLongPoll hasn't been called yet.\n if (this.alive) {\n this.newRequest_();\n }\n }\n\n /**\n * Add a script tag for a regular long-poll request.\n * @param {!string} url - The URL of the script tag.\n * @param {!number} serial - The serial number of the request.\n * @private\n */\n private addLongPollTag_(url: string, serial: number) {\n //remember that we sent this request.\n this.outstandingRequests.add(serial);\n\n const doNewRequest = () => {\n this.outstandingRequests.delete(serial);\n this.newRequest_();\n };\n\n // If this request doesn't return on its own accord (by the server sending us some data), we'll\n // create a new one after the KEEPALIVE interval to make sure we always keep a fresh request open.\n const keepaliveTimeout = setTimeout(\n doNewRequest,\n Math.floor(KEEPALIVE_REQUEST_INTERVAL)\n );\n\n const readyStateCB = () => {\n // Request completed. Cancel the keepalive.\n clearTimeout(keepaliveTimeout);\n\n // Trigger a new request so we can continue receiving data.\n doNewRequest();\n };\n\n this.addTag(url, readyStateCB);\n }\n\n /**\n * Add an arbitrary script tag to the iframe.\n * @param {!string} url - The URL for the script tag source.\n * @param {!function()} loadCB - A callback to be triggered once the script has loaded.\n */\n addTag(url: string, loadCB: () => void) {\n if (isNodeSdk()) {\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n (this as any).doNodeLongPoll(url, loadCB);\n } else {\n setTimeout(() => {\n try {\n // if we're already closed, don't add this poll\n if (!this.sendNewPolls) {\n return;\n }\n const newScript = this.myIFrame.doc.createElement('script');\n newScript.type = 'text/javascript';\n newScript.async = true;\n newScript.src = url;\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n newScript.onload = (newScript as any).onreadystatechange = function() {\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n const rstate = (newScript as any).readyState;\n if (!rstate || rstate === 'loaded' || rstate === 'complete') {\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n newScript.onload = (newScript as any).onreadystatechange = null;\n if (newScript.parentNode) {\n newScript.parentNode.removeChild(newScript);\n }\n loadCB();\n }\n };\n newScript.onerror = () => {\n log('Long-poll script failed to load: ' + url);\n this.sendNewPolls = false;\n this.close();\n };\n this.myIFrame.doc.body.appendChild(newScript);\n } catch (e) {\n // TODO: we should make this error visible somehow\n }\n }, Math.floor(1));\n }\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport firebase from '@firebase/app';\n\n/** The semver (www.semver.org) version of the SDK. */\nexport const SDK_VERSION = firebase.SDK_VERSION;\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { RepoInfo } from '../core/RepoInfo';\nimport {\n assert,\n CONSTANTS as ENV_CONSTANTS,\n jsonEval,\n stringify,\n isNodeSdk\n} from '@firebase/util';\nimport { logWrapper, splitStringBySize } from '../core/util/util';\nimport { StatsManager } from '../core/stats/StatsManager';\nimport {\n FORGE_DOMAIN,\n FORGE_REF,\n LAST_SESSION_PARAM,\n PROTOCOL_VERSION,\n REFERER_PARAM,\n TRANSPORT_SESSION_PARAM,\n VERSION_PARAM,\n WEBSOCKET\n} from './Constants';\nimport { PersistentStorage } from '../core/storage/storage';\nimport { Transport } from './Transport';\nimport { StatsCollection } from '../core/stats/StatsCollection';\nimport { SDK_VERSION } from '../core/version';\n\n// eslint-disable-next-line @typescript-eslint/no-explicit-any\ndeclare const MozWebSocket: any;\n\nconst WEBSOCKET_MAX_FRAME_SIZE = 16384;\nconst WEBSOCKET_KEEPALIVE_INTERVAL = 45000;\n\nlet WebSocketImpl = null;\nif (typeof MozWebSocket !== 'undefined') {\n WebSocketImpl = MozWebSocket;\n} else if (typeof WebSocket !== 'undefined') {\n WebSocketImpl = WebSocket;\n}\n\nexport function setWebSocketImpl(impl) {\n WebSocketImpl = impl;\n}\n\n/**\n * Create a new websocket connection with the given callbacks.\n * @constructor\n * @implements {Transport}\n */\nexport class WebSocketConnection implements Transport {\n keepaliveTimer: number | null = null;\n frames: string[] | null = null;\n totalFrames = 0;\n bytesSent = 0;\n bytesReceived = 0;\n connURL: string;\n onDisconnect: (a?: boolean) => void;\n onMessage: (msg: {}) => void;\n mySock: WebSocket | null;\n private log_: (...a: unknown[]) => void;\n private stats_: StatsCollection;\n private everConnected_: boolean;\n private isClosed_: boolean;\n\n /**\n * @param connId identifier for this transport\n * @param repoInfo The info for the websocket endpoint.\n * @param applicationId The Firebase App ID for this project.\n * @param transportSessionId Optional transportSessionId if this is connecting to an existing transport\n * session\n * @param lastSessionId Optional lastSessionId if there was a previous connection\n */\n constructor(\n public connId: string,\n repoInfo: RepoInfo,\n private applicationId?: string,\n transportSessionId?: string,\n lastSessionId?: string\n ) {\n this.log_ = logWrapper(this.connId);\n this.stats_ = StatsManager.getCollection(repoInfo);\n this.connURL = WebSocketConnection.connectionURL_(\n repoInfo,\n transportSessionId,\n lastSessionId\n );\n }\n\n /**\n * @param {RepoInfo} repoInfo The info for the websocket endpoint.\n * @param {string=} transportSessionId Optional transportSessionId if this is connecting to an existing transport\n * session\n * @param {string=} lastSessionId Optional lastSessionId if there was a previous connection\n * @return {string} connection url\n * @private\n */\n private static connectionURL_(\n repoInfo: RepoInfo,\n transportSessionId?: string,\n lastSessionId?: string\n ): string {\n const urlParams: { [k: string]: string } = {};\n urlParams[VERSION_PARAM] = PROTOCOL_VERSION;\n\n if (\n !isNodeSdk() &&\n typeof location !== 'undefined' &&\n location.href &&\n location.href.indexOf(FORGE_DOMAIN) !== -1\n ) {\n urlParams[REFERER_PARAM] = FORGE_REF;\n }\n if (transportSessionId) {\n urlParams[TRANSPORT_SESSION_PARAM] = transportSessionId;\n }\n if (lastSessionId) {\n urlParams[LAST_SESSION_PARAM] = lastSessionId;\n }\n return repoInfo.connectionURL(WEBSOCKET, urlParams);\n }\n\n /**\n *\n * @param onMessage Callback when messages arrive\n * @param onDisconnect Callback with connection lost.\n */\n open(onMessage: (msg: {}) => void, onDisconnect: (a?: boolean) => void) {\n this.onDisconnect = onDisconnect;\n this.onMessage = onMessage;\n\n this.log_('Websocket connecting to ' + this.connURL);\n\n this.everConnected_ = false;\n // Assume failure until proven otherwise.\n PersistentStorage.set('previous_websocket_failure', true);\n\n try {\n if (isNodeSdk()) {\n const device = ENV_CONSTANTS.NODE_ADMIN ? 'AdminNode' : 'Node';\n // UA Format: Firebase////\n const options: { [k: string]: object } = {\n headers: {\n 'User-Agent': `Firebase/${PROTOCOL_VERSION}/${SDK_VERSION}/${process.platform}/${device}`,\n 'X-Firebase-GMPID': this.applicationId || ''\n }\n };\n\n // Plumb appropriate http_proxy environment variable into faye-websocket if it exists.\n const env = process['env'];\n const proxy =\n this.connURL.indexOf('wss://') === 0\n ? env['HTTPS_PROXY'] || env['https_proxy']\n : env['HTTP_PROXY'] || env['http_proxy'];\n\n if (proxy) {\n options['proxy'] = { origin: proxy };\n }\n\n this.mySock = new WebSocketImpl(this.connURL, [], options);\n } else {\n const options: { [k: string]: object } = {\n headers: {\n 'X-Firebase-GMPID': this.applicationId || ''\n }\n };\n this.mySock = new WebSocketImpl(this.connURL, [], options);\n }\n } catch (e) {\n this.log_('Error instantiating WebSocket.');\n const error = e.message || e.data;\n if (error) {\n this.log_(error);\n }\n this.onClosed_();\n return;\n }\n\n this.mySock.onopen = () => {\n this.log_('Websocket connected.');\n this.everConnected_ = true;\n };\n\n this.mySock.onclose = () => {\n this.log_('Websocket connection was disconnected.');\n this.mySock = null;\n this.onClosed_();\n };\n\n this.mySock.onmessage = m => {\n this.handleIncomingFrame(m as {});\n };\n\n this.mySock.onerror = e => {\n this.log_('WebSocket error. Closing connection.');\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n const error = (e as any).message || (e as any).data;\n if (error) {\n this.log_(error);\n }\n this.onClosed_();\n };\n }\n\n /**\n * No-op for websockets, we don't need to do anything once the connection is confirmed as open\n */\n start() {}\n\n static forceDisallow_: boolean;\n\n static forceDisallow() {\n WebSocketConnection.forceDisallow_ = true;\n }\n\n static isAvailable(): boolean {\n let isOldAndroid = false;\n if (typeof navigator !== 'undefined' && navigator.userAgent) {\n const oldAndroidRegex = /Android ([0-9]{0,}\\.[0-9]{0,})/;\n const oldAndroidMatch = navigator.userAgent.match(oldAndroidRegex);\n if (oldAndroidMatch && oldAndroidMatch.length > 1) {\n if (parseFloat(oldAndroidMatch[1]) < 4.4) {\n isOldAndroid = true;\n }\n }\n }\n\n return (\n !isOldAndroid &&\n WebSocketImpl !== null &&\n !WebSocketConnection.forceDisallow_\n );\n }\n\n /**\n * Number of response before we consider the connection \"healthy.\"\n * @type {number}\n */\n static responsesRequiredToBeHealthy = 2;\n\n /**\n * Time to wait for the connection te become healthy before giving up.\n * @type {number}\n */\n static healthyTimeout = 30000;\n\n /**\n * Returns true if we previously failed to connect with this transport.\n * @return {boolean}\n */\n static previouslyFailed(): boolean {\n // If our persistent storage is actually only in-memory storage,\n // we default to assuming that it previously failed to be safe.\n return (\n PersistentStorage.isInMemoryStorage ||\n PersistentStorage.get('previous_websocket_failure') === true\n );\n }\n\n markConnectionHealthy() {\n PersistentStorage.remove('previous_websocket_failure');\n }\n\n private appendFrame_(data: string) {\n this.frames.push(data);\n if (this.frames.length === this.totalFrames) {\n const fullMess = this.frames.join('');\n this.frames = null;\n const jsonMess = jsonEval(fullMess) as object;\n\n //handle the message\n this.onMessage(jsonMess);\n }\n }\n\n /**\n * @param {number} frameCount The number of frames we are expecting from the server\n * @private\n */\n private handleNewFrameCount_(frameCount: number) {\n this.totalFrames = frameCount;\n this.frames = [];\n }\n\n /**\n * Attempts to parse a frame count out of some text. If it can't, assumes a value of 1\n * @param {!String} data\n * @return {?String} Any remaining data to be process, or null if there is none\n * @private\n */\n private extractFrameCount_(data: string): string | null {\n assert(this.frames === null, 'We already have a frame buffer');\n // TODO: The server is only supposed to send up to 9999 frames (i.e. length <= 4), but that isn't being enforced\n // currently. So allowing larger frame counts (length <= 6). See https://app.asana.com/0/search/8688598998380/8237608042508\n if (data.length <= 6) {\n const frameCount = Number(data);\n if (!isNaN(frameCount)) {\n this.handleNewFrameCount_(frameCount);\n return null;\n }\n }\n this.handleNewFrameCount_(1);\n return data;\n }\n\n /**\n * Process a websocket frame that has arrived from the server.\n * @param mess The frame data\n */\n handleIncomingFrame(mess: { [k: string]: unknown }) {\n if (this.mySock === null) {\n return; // Chrome apparently delivers incoming packets even after we .close() the connection sometimes.\n }\n const data = mess['data'] as string;\n this.bytesReceived += data.length;\n this.stats_.incrementCounter('bytes_received', data.length);\n\n this.resetKeepAlive();\n\n if (this.frames !== null) {\n // we're buffering\n this.appendFrame_(data);\n } else {\n // try to parse out a frame count, otherwise, assume 1 and process it\n const remainingData = this.extractFrameCount_(data);\n if (remainingData !== null) {\n this.appendFrame_(remainingData);\n }\n }\n }\n\n /**\n * Send a message to the server\n * @param {Object} data The JSON object to transmit\n */\n send(data: {}) {\n this.resetKeepAlive();\n\n const dataStr = stringify(data);\n this.bytesSent += dataStr.length;\n this.stats_.incrementCounter('bytes_sent', dataStr.length);\n\n //We can only fit a certain amount in each websocket frame, so we need to split this request\n //up into multiple pieces if it doesn't fit in one request.\n\n const dataSegs = splitStringBySize(dataStr, WEBSOCKET_MAX_FRAME_SIZE);\n\n //Send the length header\n if (dataSegs.length > 1) {\n this.sendString_(String(dataSegs.length));\n }\n\n //Send the actual data in segments.\n for (let i = 0; i < dataSegs.length; i++) {\n this.sendString_(dataSegs[i]);\n }\n }\n\n private shutdown_() {\n this.isClosed_ = true;\n if (this.keepaliveTimer) {\n clearInterval(this.keepaliveTimer);\n this.keepaliveTimer = null;\n }\n\n if (this.mySock) {\n this.mySock.close();\n this.mySock = null;\n }\n }\n\n private onClosed_() {\n if (!this.isClosed_) {\n this.log_('WebSocket is closing itself');\n this.shutdown_();\n\n // since this is an internal close, trigger the close listener\n if (this.onDisconnect) {\n this.onDisconnect(this.everConnected_);\n this.onDisconnect = null;\n }\n }\n }\n\n /**\n * External-facing close handler.\n * Close the websocket and kill the connection.\n */\n close() {\n if (!this.isClosed_) {\n this.log_('WebSocket is being closed');\n this.shutdown_();\n }\n }\n\n /**\n * Kill the current keepalive timer and start a new one, to ensure that it always fires N seconds after\n * the last activity.\n */\n resetKeepAlive() {\n clearInterval(this.keepaliveTimer);\n this.keepaliveTimer = setInterval(() => {\n //If there has been no websocket activity for a while, send a no-op\n if (this.mySock) {\n this.sendString_('0');\n }\n this.resetKeepAlive();\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n }, Math.floor(WEBSOCKET_KEEPALIVE_INTERVAL)) as any;\n }\n\n /**\n * Send a string over the websocket.\n *\n * @param {string} str String to send.\n * @private\n */\n private sendString_(str: string) {\n // Firefox seems to sometimes throw exceptions (NS_ERROR_UNEXPECTED) from websocket .send()\n // calls for some unknown reason. We treat these as an error and disconnect.\n // See https://app.asana.com/0/58926111402292/68021340250410\n try {\n this.mySock.send(str);\n } catch (e) {\n this.log_(\n 'Exception thrown from WebSocket.send():',\n e.message || e.data,\n 'Closing connection.'\n );\n setTimeout(this.onClosed_.bind(this), 0);\n }\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { BrowserPollConnection } from './BrowserPollConnection';\nimport { WebSocketConnection } from './WebSocketConnection';\nimport { warn } from '../core/util/util';\nimport { TransportConstructor } from './Transport';\nimport { RepoInfo } from '../core/RepoInfo';\n\n/**\n * Currently simplistic, this class manages what transport a Connection should use at various stages of its\n * lifecycle.\n *\n * It starts with longpolling in a browser, and httppolling on node. It then upgrades to websockets if\n * they are available.\n * @constructor\n */\nexport class TransportManager {\n private transports_: TransportConstructor[];\n\n /**\n * @const\n * @type {!Array.}\n */\n static get ALL_TRANSPORTS() {\n return [BrowserPollConnection, WebSocketConnection];\n }\n\n /**\n * @param {!RepoInfo} repoInfo Metadata around the namespace we're connecting to\n */\n constructor(repoInfo: RepoInfo) {\n this.initTransports_(repoInfo);\n }\n\n /**\n * @param {!RepoInfo} repoInfo\n * @private\n */\n private initTransports_(repoInfo: RepoInfo) {\n const isWebSocketsAvailable: boolean =\n WebSocketConnection && WebSocketConnection['isAvailable']();\n let isSkipPollConnection =\n isWebSocketsAvailable && !WebSocketConnection.previouslyFailed();\n\n if (repoInfo.webSocketOnly) {\n if (!isWebSocketsAvailable) {\n warn(\n \"wss:// URL used, but browser isn't known to support websockets. Trying anyway.\"\n );\n }\n\n isSkipPollConnection = true;\n }\n\n if (isSkipPollConnection) {\n this.transports_ = [WebSocketConnection];\n } else {\n const transports = (this.transports_ = [] as TransportConstructor[]);\n for (const transport of TransportManager.ALL_TRANSPORTS) {\n if (transport && transport['isAvailable']()) {\n transports.push(transport);\n }\n }\n }\n }\n\n /**\n * @return {function(new:Transport, !string, !RepoInfo, string=, string=)} The constructor for the\n * initial transport to use\n */\n initialTransport(): TransportConstructor {\n if (this.transports_.length > 0) {\n return this.transports_[0];\n } else {\n throw new Error('No transports available');\n }\n }\n\n /**\n * @return {?function(new:Transport, function(),function(), string=)} The constructor for the next\n * transport, or null\n */\n upgradeTransport(): TransportConstructor | null {\n if (this.transports_.length > 1) {\n return this.transports_[1];\n } else {\n return null;\n }\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport {\n error,\n logWrapper,\n requireKey,\n setTimeoutNonBlocking,\n warn\n} from '../core/util/util';\nimport { PersistentStorage } from '../core/storage/storage';\nimport { PROTOCOL_VERSION } from './Constants';\nimport { TransportManager } from './TransportManager';\nimport { RepoInfo } from '../core/RepoInfo';\nimport { Transport, TransportConstructor } from './Transport';\nimport { Indexable } from '../core/util/misc';\n\n// Abort upgrade attempt if it takes longer than 60s.\nconst UPGRADE_TIMEOUT = 60000;\n\n// For some transports (WebSockets), we need to \"validate\" the transport by exchanging a few requests and responses.\n// If we haven't sent enough requests within 5s, we'll start sending noop ping requests.\nconst DELAY_BEFORE_SENDING_EXTRA_REQUESTS = 5000;\n\n// If the initial data sent triggers a lot of bandwidth (i.e. it's a large put or a listen for a large amount of data)\n// then we may not be able to exchange our ping/pong requests within the healthy timeout. So if we reach the timeout\n// but we've sent/received enough bytes, we don't cancel the connection.\nconst BYTES_SENT_HEALTHY_OVERRIDE = 10 * 1024;\nconst BYTES_RECEIVED_HEALTHY_OVERRIDE = 100 * 1024;\n\nconst enum RealtimeState {\n CONNECTING,\n CONNECTED,\n DISCONNECTED\n}\n\nconst MESSAGE_TYPE = 't';\nconst MESSAGE_DATA = 'd';\nconst CONTROL_SHUTDOWN = 's';\nconst CONTROL_RESET = 'r';\nconst CONTROL_ERROR = 'e';\nconst CONTROL_PONG = 'o';\nconst SWITCH_ACK = 'a';\nconst END_TRANSMISSION = 'n';\nconst PING = 'p';\n\nconst SERVER_HELLO = 'h';\n\n/**\n * Creates a new real-time connection to the server using whichever method works\n * best in the current browser.\n *\n * @constructor\n */\nexport class Connection {\n connectionCount = 0;\n pendingDataMessages: unknown[] = [];\n sessionId: string;\n\n private conn_: Transport;\n private healthyTimeout_: number;\n private isHealthy_: boolean;\n private log_: (...args: unknown[]) => void;\n private primaryResponsesRequired_: number;\n private rx_: Transport;\n private secondaryConn_: Transport;\n private secondaryResponsesRequired_: number;\n private state_ = RealtimeState.CONNECTING;\n private transportManager_: TransportManager;\n private tx_: Transport;\n\n /**\n * @param id - an id for this connection\n * @param repoInfo_ - the info for the endpoint to connect to\n * @param applicationId_ - the Firebase App ID for this project\n * @param onMessage_ - the callback to be triggered when a server-push message arrives\n * @param onReady_ - the callback to be triggered when this connection is ready to send messages.\n * @param onDisconnect_ - the callback to be triggered when a connection was lost\n * @param onKill_ - the callback to be triggered when this connection has permanently shut down.\n * @param lastSessionId - last session id in persistent connection. is used to clean up old session in real-time server\n */\n constructor(\n public id: string,\n private repoInfo_: RepoInfo,\n private applicationId_: string | undefined,\n private onMessage_: (a: {}) => void,\n private onReady_: (a: number, b: string) => void,\n private onDisconnect_: () => void,\n private onKill_: (a: string) => void,\n public lastSessionId?: string\n ) {\n this.log_ = logWrapper('c:' + this.id + ':');\n this.transportManager_ = new TransportManager(repoInfo_);\n this.log_('Connection created');\n this.start_();\n }\n\n /**\n * Starts a connection attempt\n * @private\n */\n private start_(): void {\n const conn = this.transportManager_.initialTransport();\n this.conn_ = new conn(\n this.nextTransportId_(),\n this.repoInfo_,\n this.applicationId_,\n undefined,\n this.lastSessionId\n );\n\n // For certain transports (WebSockets), we need to send and receive several messages back and forth before we\n // can consider the transport healthy.\n this.primaryResponsesRequired_ = conn['responsesRequiredToBeHealthy'] || 0;\n\n const onMessageReceived = this.connReceiver_(this.conn_);\n const onConnectionLost = this.disconnReceiver_(this.conn_);\n this.tx_ = this.conn_;\n this.rx_ = this.conn_;\n this.secondaryConn_ = null;\n this.isHealthy_ = false;\n\n /*\n * Firefox doesn't like when code from one iframe tries to create another iframe by way of the parent frame.\n * This can occur in the case of a redirect, i.e. we guessed wrong on what server to connect to and received a reset.\n * Somehow, setTimeout seems to make this ok. That doesn't make sense from a security perspective, since you should\n * still have the context of your originating frame.\n */\n setTimeout(() => {\n // this.conn_ gets set to null in some of the tests. Check to make sure it still exists before using it\n this.conn_ && this.conn_.open(onMessageReceived, onConnectionLost);\n }, Math.floor(0));\n\n const healthyTimeoutMS = conn['healthyTimeout'] || 0;\n if (healthyTimeoutMS > 0) {\n this.healthyTimeout_ = setTimeoutNonBlocking(() => {\n this.healthyTimeout_ = null;\n if (!this.isHealthy_) {\n if (\n this.conn_ &&\n this.conn_.bytesReceived > BYTES_RECEIVED_HEALTHY_OVERRIDE\n ) {\n this.log_(\n 'Connection exceeded healthy timeout but has received ' +\n this.conn_.bytesReceived +\n ' bytes. Marking connection healthy.'\n );\n this.isHealthy_ = true;\n this.conn_.markConnectionHealthy();\n } else if (\n this.conn_ &&\n this.conn_.bytesSent > BYTES_SENT_HEALTHY_OVERRIDE\n ) {\n this.log_(\n 'Connection exceeded healthy timeout but has sent ' +\n this.conn_.bytesSent +\n ' bytes. Leaving connection alive.'\n );\n // NOTE: We don't want to mark it healthy, since we have no guarantee that the bytes have made it to\n // the server.\n } else {\n this.log_('Closing unhealthy connection after timeout.');\n this.close();\n }\n }\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n }, Math.floor(healthyTimeoutMS)) as any;\n }\n }\n\n /**\n * @return {!string}\n * @private\n */\n private nextTransportId_(): string {\n return 'c:' + this.id + ':' + this.connectionCount++;\n }\n\n private disconnReceiver_(conn) {\n return everConnected => {\n if (conn === this.conn_) {\n this.onConnectionLost_(everConnected);\n } else if (conn === this.secondaryConn_) {\n this.log_('Secondary connection lost.');\n this.onSecondaryConnectionLost_();\n } else {\n this.log_('closing an old connection');\n }\n };\n }\n\n private connReceiver_(conn: Transport) {\n return (message: Indexable) => {\n if (this.state_ !== RealtimeState.DISCONNECTED) {\n if (conn === this.rx_) {\n this.onPrimaryMessageReceived_(message);\n } else if (conn === this.secondaryConn_) {\n this.onSecondaryMessageReceived_(message);\n } else {\n this.log_('message on old connection');\n }\n }\n };\n }\n\n /**\n *\n * @param {Object} dataMsg An arbitrary data message to be sent to the server\n */\n sendRequest(dataMsg: object) {\n // wrap in a data message envelope and send it on\n const msg = { t: 'd', d: dataMsg };\n this.sendData_(msg);\n }\n\n tryCleanupConnection() {\n if (this.tx_ === this.secondaryConn_ && this.rx_ === this.secondaryConn_) {\n this.log_(\n 'cleaning up and promoting a connection: ' + this.secondaryConn_.connId\n );\n this.conn_ = this.secondaryConn_;\n this.secondaryConn_ = null;\n // the server will shutdown the old connection\n }\n }\n\n private onSecondaryControl_(controlData: { [k: string]: unknown }) {\n if (MESSAGE_TYPE in controlData) {\n const cmd = controlData[MESSAGE_TYPE] as string;\n if (cmd === SWITCH_ACK) {\n this.upgradeIfSecondaryHealthy_();\n } else if (cmd === CONTROL_RESET) {\n // Most likely the session wasn't valid. Abandon the switch attempt\n this.log_('Got a reset on secondary, closing it');\n this.secondaryConn_.close();\n // If we were already using this connection for something, than we need to fully close\n if (\n this.tx_ === this.secondaryConn_ ||\n this.rx_ === this.secondaryConn_\n ) {\n this.close();\n }\n } else if (cmd === CONTROL_PONG) {\n this.log_('got pong on secondary.');\n this.secondaryResponsesRequired_--;\n this.upgradeIfSecondaryHealthy_();\n }\n }\n }\n\n private onSecondaryMessageReceived_(parsedData: Indexable) {\n const layer: string = requireKey('t', parsedData) as string;\n const data: unknown = requireKey('d', parsedData);\n if (layer === 'c') {\n this.onSecondaryControl_(data as Indexable);\n } else if (layer === 'd') {\n // got a data message, but we're still second connection. Need to buffer it up\n this.pendingDataMessages.push(data);\n } else {\n throw new Error('Unknown protocol layer: ' + layer);\n }\n }\n\n private upgradeIfSecondaryHealthy_() {\n if (this.secondaryResponsesRequired_ <= 0) {\n this.log_('Secondary connection is healthy.');\n this.isHealthy_ = true;\n this.secondaryConn_.markConnectionHealthy();\n this.proceedWithUpgrade_();\n } else {\n // Send a ping to make sure the connection is healthy.\n this.log_('sending ping on secondary.');\n this.secondaryConn_.send({ t: 'c', d: { t: PING, d: {} } });\n }\n }\n\n private proceedWithUpgrade_() {\n // tell this connection to consider itself open\n this.secondaryConn_.start();\n // send ack\n this.log_('sending client ack on secondary');\n this.secondaryConn_.send({ t: 'c', d: { t: SWITCH_ACK, d: {} } });\n\n // send end packet on primary transport, switch to sending on this one\n // can receive on this one, buffer responses until end received on primary transport\n this.log_('Ending transmission on primary');\n this.conn_.send({ t: 'c', d: { t: END_TRANSMISSION, d: {} } });\n this.tx_ = this.secondaryConn_;\n\n this.tryCleanupConnection();\n }\n\n private onPrimaryMessageReceived_(parsedData: { [k: string]: unknown }) {\n // Must refer to parsedData properties in quotes, so closure doesn't touch them.\n const layer: string = requireKey('t', parsedData) as string;\n const data: unknown = requireKey('d', parsedData);\n if (layer === 'c') {\n this.onControl_(data as { [k: string]: unknown });\n } else if (layer === 'd') {\n this.onDataMessage_(data);\n }\n }\n\n private onDataMessage_(message: unknown) {\n this.onPrimaryResponse_();\n\n // We don't do anything with data messages, just kick them up a level\n this.onMessage_(message);\n }\n\n private onPrimaryResponse_() {\n if (!this.isHealthy_) {\n this.primaryResponsesRequired_--;\n if (this.primaryResponsesRequired_ <= 0) {\n this.log_('Primary connection is healthy.');\n this.isHealthy_ = true;\n this.conn_.markConnectionHealthy();\n }\n }\n }\n\n private onControl_(controlData: { [k: string]: unknown }) {\n const cmd: string = requireKey(MESSAGE_TYPE, controlData) as string;\n if (MESSAGE_DATA in controlData) {\n const payload = controlData[MESSAGE_DATA];\n if (cmd === SERVER_HELLO) {\n this.onHandshake_(\n payload as {\n ts: number;\n v: string;\n h: string;\n s: string;\n }\n );\n } else if (cmd === END_TRANSMISSION) {\n this.log_('recvd end transmission on primary');\n this.rx_ = this.secondaryConn_;\n for (let i = 0; i < this.pendingDataMessages.length; ++i) {\n this.onDataMessage_(this.pendingDataMessages[i]);\n }\n this.pendingDataMessages = [];\n this.tryCleanupConnection();\n } else if (cmd === CONTROL_SHUTDOWN) {\n // This was previously the 'onKill' callback passed to the lower-level connection\n // payload in this case is the reason for the shutdown. Generally a human-readable error\n this.onConnectionShutdown_(payload as string);\n } else if (cmd === CONTROL_RESET) {\n // payload in this case is the host we should contact\n this.onReset_(payload as string);\n } else if (cmd === CONTROL_ERROR) {\n error('Server Error: ' + payload);\n } else if (cmd === CONTROL_PONG) {\n this.log_('got pong on primary.');\n this.onPrimaryResponse_();\n this.sendPingOnPrimaryIfNecessary_();\n } else {\n error('Unknown control packet command: ' + cmd);\n }\n }\n }\n\n /**\n *\n * @param {Object} handshake The handshake data returned from the server\n * @private\n */\n private onHandshake_(handshake: {\n ts: number;\n v: string;\n h: string;\n s: string;\n }): void {\n const timestamp = handshake.ts;\n const version = handshake.v;\n const host = handshake.h;\n this.sessionId = handshake.s;\n this.repoInfo_.updateHost(host);\n // if we've already closed the connection, then don't bother trying to progress further\n if (this.state_ === RealtimeState.CONNECTING) {\n this.conn_.start();\n this.onConnectionEstablished_(this.conn_, timestamp);\n if (PROTOCOL_VERSION !== version) {\n warn('Protocol version mismatch detected');\n }\n // TODO: do we want to upgrade? when? maybe a delay?\n this.tryStartUpgrade_();\n }\n }\n\n private tryStartUpgrade_() {\n const conn = this.transportManager_.upgradeTransport();\n if (conn) {\n this.startUpgrade_(conn);\n }\n }\n\n private startUpgrade_(conn: TransportConstructor) {\n this.secondaryConn_ = new conn(\n this.nextTransportId_(),\n this.repoInfo_,\n this.applicationId_,\n this.sessionId\n );\n // For certain transports (WebSockets), we need to send and receive several messages back and forth before we\n // can consider the transport healthy.\n this.secondaryResponsesRequired_ =\n conn['responsesRequiredToBeHealthy'] || 0;\n\n const onMessage = this.connReceiver_(this.secondaryConn_);\n const onDisconnect = this.disconnReceiver_(this.secondaryConn_);\n this.secondaryConn_.open(onMessage, onDisconnect);\n\n // If we haven't successfully upgraded after UPGRADE_TIMEOUT, give up and kill the secondary.\n setTimeoutNonBlocking(() => {\n if (this.secondaryConn_) {\n this.log_('Timed out trying to upgrade.');\n this.secondaryConn_.close();\n }\n }, Math.floor(UPGRADE_TIMEOUT));\n }\n\n private onReset_(host: string) {\n this.log_('Reset packet received. New host: ' + host);\n this.repoInfo_.updateHost(host);\n // TODO: if we're already \"connected\", we need to trigger a disconnect at the next layer up.\n // We don't currently support resets after the connection has already been established\n if (this.state_ === RealtimeState.CONNECTED) {\n this.close();\n } else {\n // Close whatever connections we have open and start again.\n this.closeConnections_();\n this.start_();\n }\n }\n\n private onConnectionEstablished_(conn: Transport, timestamp: number) {\n this.log_('Realtime connection established.');\n this.conn_ = conn;\n this.state_ = RealtimeState.CONNECTED;\n\n if (this.onReady_) {\n this.onReady_(timestamp, this.sessionId);\n this.onReady_ = null;\n }\n\n // If after 5 seconds we haven't sent enough requests to the server to get the connection healthy,\n // send some pings.\n if (this.primaryResponsesRequired_ === 0) {\n this.log_('Primary connection is healthy.');\n this.isHealthy_ = true;\n } else {\n setTimeoutNonBlocking(() => {\n this.sendPingOnPrimaryIfNecessary_();\n }, Math.floor(DELAY_BEFORE_SENDING_EXTRA_REQUESTS));\n }\n }\n\n private sendPingOnPrimaryIfNecessary_() {\n // If the connection isn't considered healthy yet, we'll send a noop ping packet request.\n if (!this.isHealthy_ && this.state_ === RealtimeState.CONNECTED) {\n this.log_('sending ping on primary.');\n this.sendData_({ t: 'c', d: { t: PING, d: {} } });\n }\n }\n\n private onSecondaryConnectionLost_() {\n const conn = this.secondaryConn_;\n this.secondaryConn_ = null;\n if (this.tx_ === conn || this.rx_ === conn) {\n // we are relying on this connection already in some capacity. Therefore, a failure is real\n this.close();\n }\n }\n\n /**\n *\n * @param {boolean} everConnected Whether or not the connection ever reached a server. Used to determine if\n * we should flush the host cache\n * @private\n */\n private onConnectionLost_(everConnected: boolean) {\n this.conn_ = null;\n\n // NOTE: IF you're seeing a Firefox error for this line, I think it might be because it's getting\n // called on window close and RealtimeState.CONNECTING is no longer defined. Just a guess.\n if (!everConnected && this.state_ === RealtimeState.CONNECTING) {\n this.log_('Realtime connection failed.');\n // Since we failed to connect at all, clear any cached entry for this namespace in case the machine went away\n if (this.repoInfo_.isCacheableHost()) {\n PersistentStorage.remove('host:' + this.repoInfo_.host);\n // reset the internal host to what we would show the user, i.e. .firebaseio.com\n this.repoInfo_.internalHost = this.repoInfo_.host;\n }\n } else if (this.state_ === RealtimeState.CONNECTED) {\n this.log_('Realtime connection lost.');\n }\n\n this.close();\n }\n\n /**\n *\n * @param {string} reason\n * @private\n */\n private onConnectionShutdown_(reason: string) {\n this.log_('Connection shutdown command received. Shutting down...');\n\n if (this.onKill_) {\n this.onKill_(reason);\n this.onKill_ = null;\n }\n\n // We intentionally don't want to fire onDisconnect (kill is a different case),\n // so clear the callback.\n this.onDisconnect_ = null;\n\n this.close();\n }\n\n private sendData_(data: object) {\n if (this.state_ !== RealtimeState.CONNECTED) {\n throw 'Connection is not connected';\n } else {\n this.tx_.send(data);\n }\n }\n\n /**\n * Cleans up this connection, calling the appropriate callbacks\n */\n close() {\n if (this.state_ !== RealtimeState.DISCONNECTED) {\n this.log_('Closing realtime connection.');\n this.state_ = RealtimeState.DISCONNECTED;\n\n this.closeConnections_();\n\n if (this.onDisconnect_) {\n this.onDisconnect_();\n this.onDisconnect_ = null;\n }\n }\n }\n\n /**\n *\n * @private\n */\n private closeConnections_() {\n this.log_('Shutting down all connections');\n if (this.conn_) {\n this.conn_.close();\n this.conn_ = null;\n }\n\n if (this.secondaryConn_) {\n this.secondaryConn_.close();\n this.secondaryConn_ = null;\n }\n\n if (this.healthyTimeout_) {\n clearTimeout(this.healthyTimeout_);\n this.healthyTimeout_ = null;\n }\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { Query } from '../api/Query';\n\n/**\n * Interface defining the set of actions that can be performed against the Firebase server\n * (basically corresponds to our wire protocol).\n *\n * @interface\n */\nexport abstract class ServerActions {\n /**\n * @param {!Query} query\n * @param {function():string} currentHashFn\n * @param {?number} tag\n * @param {function(string, *)} onComplete\n */\n abstract listen(\n query: Query,\n currentHashFn: () => string,\n tag: number | null,\n onComplete: (a: string, b: unknown) => void\n ): void;\n\n /**\n * Remove a listen.\n *\n * @param {!Query} query\n * @param {?number} tag\n */\n abstract unlisten(query: Query, tag: number | null): void;\n\n /**\n * @param {string} pathString\n * @param {*} data\n * @param {function(string, string)=} onComplete\n * @param {string=} hash\n */\n put(\n pathString: string,\n data: unknown,\n onComplete?: (a: string, b: string) => void,\n hash?: string\n ) {}\n\n /**\n * @param {string} pathString\n * @param {*} data\n * @param {function(string, ?string)} onComplete\n * @param {string=} hash\n */\n merge(\n pathString: string,\n data: unknown,\n onComplete: (a: string, b: string | null) => void,\n hash?: string\n ) {}\n\n /**\n * Refreshes the auth token for the current connection.\n * @param {string} token The authentication token\n */\n refreshAuthToken(token: string) {}\n\n /**\n * @param {string} pathString\n * @param {*} data\n * @param {function(string, string)=} onComplete\n */\n onDisconnectPut(\n pathString: string,\n data: unknown,\n onComplete?: (a: string, b: string) => void\n ) {}\n\n /**\n * @param {string} pathString\n * @param {*} data\n * @param {function(string, string)=} onComplete\n */\n onDisconnectMerge(\n pathString: string,\n data: unknown,\n onComplete?: (a: string, b: string) => void\n ) {}\n\n /**\n * @param {string} pathString\n * @param {function(string, string)=} onComplete\n */\n onDisconnectCancel(\n pathString: string,\n onComplete?: (a: string, b: string) => void\n ) {}\n\n /**\n * @param {Object.} stats\n */\n reportStats(stats: { [k: string]: unknown }) {}\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport {\n contains,\n isEmpty,\n safeGet,\n CONSTANTS,\n stringify,\n assert,\n isAdmin,\n isValidFormat,\n isMobileCordova,\n isReactNative,\n isNodeSdk\n} from '@firebase/util';\n\nimport { error, log, logWrapper, warn, ObjectToUniqueKey } from './util/util';\nimport { Path } from './util/Path';\nimport { VisibilityMonitor } from './util/VisibilityMonitor';\nimport { OnlineMonitor } from './util/OnlineMonitor';\n\nimport { Connection } from '../realtime/Connection';\n\nimport { ServerActions } from './ServerActions';\nimport { AuthTokenProvider } from './AuthTokenProvider';\nimport { RepoInfo } from './RepoInfo';\nimport { Query } from '../api/Query';\nimport { SDK_VERSION } from './version';\n\nconst RECONNECT_MIN_DELAY = 1000;\nconst RECONNECT_MAX_DELAY_DEFAULT = 60 * 5 * 1000; // 5 minutes in milliseconds (Case: 1858)\nconst RECONNECT_MAX_DELAY_FOR_ADMINS = 30 * 1000; // 30 seconds for admin clients (likely to be a backend server)\nconst RECONNECT_DELAY_MULTIPLIER = 1.3;\nconst RECONNECT_DELAY_RESET_TIMEOUT = 30000; // Reset delay back to MIN_DELAY after being connected for 30sec.\nconst SERVER_KILL_INTERRUPT_REASON = 'server_kill';\n\n// If auth fails repeatedly, we'll assume something is wrong and log a warning / back off.\nconst INVALID_AUTH_TOKEN_THRESHOLD = 3;\n\ninterface ListenSpec {\n onComplete(s: string, p?: unknown): void;\n\n hashFn(): string;\n\n query: Query;\n tag: number | null;\n}\n\ninterface OnDisconnectRequest {\n pathString: string;\n action: string;\n data: unknown;\n onComplete?: (a: string, b: string) => void;\n}\n\ninterface OutstandingPut {\n action: string;\n request: object;\n queued?: boolean;\n onComplete: (a: string, b?: string) => void;\n}\n\n/**\n * Firebase connection. Abstracts wire protocol and handles reconnecting.\n *\n * NOTE: All JSON objects sent to the realtime connection must have property names enclosed\n * in quotes to make sure the closure compiler does not minify them.\n */\nexport class PersistentConnection extends ServerActions {\n // Used for diagnostic logging.\n id = PersistentConnection.nextPersistentConnectionId_++;\n private log_ = logWrapper('p:' + this.id + ':');\n\n private interruptReasons_: { [reason: string]: boolean } = {};\n /** Map> */\n private readonly listens: Map<\n /* path */ string,\n Map\n > = new Map();\n private outstandingPuts_: OutstandingPut[] = [];\n private outstandingPutCount_ = 0;\n private onDisconnectRequestQueue_: OnDisconnectRequest[] = [];\n private connected_ = false;\n private reconnectDelay_ = RECONNECT_MIN_DELAY;\n private maxReconnectDelay_ = RECONNECT_MAX_DELAY_DEFAULT;\n private securityDebugCallback_: ((a: object) => void) | null = null;\n lastSessionId: string | null = null;\n\n private establishConnectionTimer_: number | null = null;\n\n private visible_: boolean = false;\n\n // Before we get connected, we keep a queue of pending messages to send.\n private requestCBHash_: { [k: number]: (a: unknown) => void } = {};\n private requestNumber_ = 0;\n\n private realtime_: {\n sendRequest(a: object): void;\n close(): void;\n } | null = null;\n\n private authToken_: string | null = null;\n private forceTokenRefresh_ = false;\n private invalidAuthTokenCount_ = 0;\n\n private firstConnection_ = true;\n private lastConnectionAttemptTime_: number | null = null;\n private lastConnectionEstablishedTime_: number | null = null;\n\n private static nextPersistentConnectionId_ = 0;\n\n /**\n * Counter for number of connections created. Mainly used for tagging in the logs\n */\n private static nextConnectionId_ = 0;\n\n /**\n * @implements {ServerActions}\n * @param repoInfo_ Data about the namespace we are connecting to\n * @param applicationId_ The Firebase App ID for this project\n * @param onDataUpdate_ A callback for new data from the server\n */\n constructor(\n private repoInfo_: RepoInfo,\n private applicationId_: string,\n private onDataUpdate_: (\n a: string,\n b: unknown,\n c: boolean,\n d: number | null\n ) => void,\n private onConnectStatus_: (a: boolean) => void,\n private onServerInfoUpdate_: (a: unknown) => void,\n private authTokenProvider_: AuthTokenProvider,\n private authOverride_?: object | null\n ) {\n super();\n\n if (authOverride_ && !isNodeSdk()) {\n throw new Error(\n 'Auth override specified in options, but not supported on non Node.js platforms'\n );\n }\n this.scheduleConnect_(0);\n\n VisibilityMonitor.getInstance().on('visible', this.onVisible_, this);\n\n if (repoInfo_.host.indexOf('fblocal') === -1) {\n OnlineMonitor.getInstance().on('online', this.onOnline_, this);\n }\n }\n\n protected sendRequest(\n action: string,\n body: unknown,\n onResponse?: (a: unknown) => void\n ) {\n const curReqNum = ++this.requestNumber_;\n\n const msg = { r: curReqNum, a: action, b: body };\n this.log_(stringify(msg));\n assert(\n this.connected_,\n \"sendRequest call when we're not connected not allowed.\"\n );\n this.realtime_.sendRequest(msg);\n if (onResponse) {\n this.requestCBHash_[curReqNum] = onResponse;\n }\n }\n\n /**\n * @inheritDoc\n */\n listen(\n query: Query,\n currentHashFn: () => string,\n tag: number | null,\n onComplete: (a: string, b: unknown) => void\n ) {\n const queryId = query.queryIdentifier();\n const pathString = query.path.toString();\n this.log_('Listen called for ' + pathString + ' ' + queryId);\n if (!this.listens.has(pathString)) {\n this.listens.set(pathString, new Map());\n }\n assert(\n query.getQueryParams().isDefault() ||\n !query.getQueryParams().loadsAllData(),\n 'listen() called for non-default but complete query'\n );\n assert(\n !this.listens.get(pathString)!.has(queryId),\n 'listen() called twice for same path/queryId.'\n );\n const listenSpec: ListenSpec = {\n onComplete,\n hashFn: currentHashFn,\n query,\n tag\n };\n this.listens.get(pathString)!.set(queryId, listenSpec);\n\n if (this.connected_) {\n this.sendListen_(listenSpec);\n }\n }\n\n private sendListen_(listenSpec: ListenSpec) {\n const query = listenSpec.query;\n const pathString = query.path.toString();\n const queryId = query.queryIdentifier();\n this.log_('Listen on ' + pathString + ' for ' + queryId);\n const req: { [k: string]: unknown } = { /*path*/ p: pathString };\n\n const action = 'q';\n\n // Only bother to send query if it's non-default.\n if (listenSpec.tag) {\n req['q'] = query.queryObject();\n req['t'] = listenSpec.tag;\n }\n\n req[/*hash*/ 'h'] = listenSpec.hashFn();\n\n this.sendRequest(action, req, (message: { [k: string]: unknown }) => {\n const payload: unknown = message[/*data*/ 'd'];\n const status = message[/*status*/ 's'] as string;\n\n // print warnings in any case...\n PersistentConnection.warnOnListenWarnings_(payload, query);\n\n const currentListenSpec =\n this.listens.get(pathString) &&\n this.listens.get(pathString)!.get(queryId);\n // only trigger actions if the listen hasn't been removed and readded\n if (currentListenSpec === listenSpec) {\n this.log_('listen response', message);\n\n if (status !== 'ok') {\n this.removeListen_(pathString, queryId);\n }\n\n if (listenSpec.onComplete) {\n listenSpec.onComplete(status, payload);\n }\n }\n });\n }\n\n private static warnOnListenWarnings_(payload: unknown, query: Query) {\n if (payload && typeof payload === 'object' && contains(payload, 'w')) {\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n const warnings = safeGet(payload as any, 'w');\n if (Array.isArray(warnings) && ~warnings.indexOf('no_index')) {\n const indexSpec =\n '\".indexOn\": \"' +\n query\n .getQueryParams()\n .getIndex()\n .toString() +\n '\"';\n const indexPath = query.path.toString();\n warn(\n `Using an unspecified index. Your data will be downloaded and ` +\n `filtered on the client. Consider adding ${indexSpec} at ` +\n `${indexPath} to your security rules for better performance.`\n );\n }\n }\n }\n\n /**\n * @inheritDoc\n */\n refreshAuthToken(token: string) {\n this.authToken_ = token;\n this.log_('Auth token refreshed');\n if (this.authToken_) {\n this.tryAuth();\n } else {\n //If we're connected we want to let the server know to unauthenticate us. If we're not connected, simply delete\n //the credential so we dont become authenticated next time we connect.\n if (this.connected_) {\n this.sendRequest('unauth', {}, () => {});\n }\n }\n\n this.reduceReconnectDelayIfAdminCredential_(token);\n }\n\n private reduceReconnectDelayIfAdminCredential_(credential: string) {\n // NOTE: This isn't intended to be bulletproof (a malicious developer can always just modify the client).\n // Additionally, we don't bother resetting the max delay back to the default if auth fails / expires.\n const isFirebaseSecret = credential && credential.length === 40;\n if (isFirebaseSecret || isAdmin(credential)) {\n this.log_(\n 'Admin auth credential detected. Reducing max reconnect time.'\n );\n this.maxReconnectDelay_ = RECONNECT_MAX_DELAY_FOR_ADMINS;\n }\n }\n\n /**\n * Attempts to authenticate with the given credentials. If the authentication attempt fails, it's triggered like\n * a auth revoked (the connection is closed).\n */\n tryAuth() {\n if (this.connected_ && this.authToken_) {\n const token = this.authToken_;\n const authMethod = isValidFormat(token) ? 'auth' : 'gauth';\n const requestData: { [k: string]: unknown } = { cred: token };\n if (this.authOverride_ === null) {\n requestData['noauth'] = true;\n } else if (typeof this.authOverride_ === 'object') {\n requestData['authvar'] = this.authOverride_;\n }\n this.sendRequest(\n authMethod,\n requestData,\n (res: { [k: string]: unknown }) => {\n const status = res[/*status*/ 's'] as string;\n const data = (res[/*data*/ 'd'] as string) || 'error';\n\n if (this.authToken_ === token) {\n if (status === 'ok') {\n this.invalidAuthTokenCount_ = 0;\n } else {\n // Triggers reconnect and force refresh for auth token\n this.onAuthRevoked_(status, data);\n }\n }\n }\n );\n }\n }\n\n /**\n * @inheritDoc\n */\n unlisten(query: Query, tag: number | null) {\n const pathString = query.path.toString();\n const queryId = query.queryIdentifier();\n\n this.log_('Unlisten called for ' + pathString + ' ' + queryId);\n\n assert(\n query.getQueryParams().isDefault() ||\n !query.getQueryParams().loadsAllData(),\n 'unlisten() called for non-default but complete query'\n );\n const listen = this.removeListen_(pathString, queryId);\n if (listen && this.connected_) {\n this.sendUnlisten_(pathString, queryId, query.queryObject(), tag);\n }\n }\n\n private sendUnlisten_(\n pathString: string,\n queryId: string,\n queryObj: object,\n tag: number | null\n ) {\n this.log_('Unlisten on ' + pathString + ' for ' + queryId);\n\n const req: { [k: string]: unknown } = { /*path*/ p: pathString };\n const action = 'n';\n // Only bother sending queryId if it's non-default.\n if (tag) {\n req['q'] = queryObj;\n req['t'] = tag;\n }\n\n this.sendRequest(action, req);\n }\n\n /**\n * @inheritDoc\n */\n onDisconnectPut(\n pathString: string,\n data: unknown,\n onComplete?: (a: string, b: string) => void\n ) {\n if (this.connected_) {\n this.sendOnDisconnect_('o', pathString, data, onComplete);\n } else {\n this.onDisconnectRequestQueue_.push({\n pathString,\n action: 'o',\n data,\n onComplete\n });\n }\n }\n\n /**\n * @inheritDoc\n */\n onDisconnectMerge(\n pathString: string,\n data: unknown,\n onComplete?: (a: string, b: string) => void\n ) {\n if (this.connected_) {\n this.sendOnDisconnect_('om', pathString, data, onComplete);\n } else {\n this.onDisconnectRequestQueue_.push({\n pathString,\n action: 'om',\n data,\n onComplete\n });\n }\n }\n\n /**\n * @inheritDoc\n */\n onDisconnectCancel(\n pathString: string,\n onComplete?: (a: string, b: string) => void\n ) {\n if (this.connected_) {\n this.sendOnDisconnect_('oc', pathString, null, onComplete);\n } else {\n this.onDisconnectRequestQueue_.push({\n pathString,\n action: 'oc',\n data: null,\n onComplete\n });\n }\n }\n\n private sendOnDisconnect_(\n action: string,\n pathString: string,\n data: unknown,\n onComplete: (a: string, b: string) => void\n ) {\n const request = { /*path*/ p: pathString, /*data*/ d: data };\n this.log_('onDisconnect ' + action, request);\n this.sendRequest(action, request, (response: { [k: string]: unknown }) => {\n if (onComplete) {\n setTimeout(() => {\n onComplete(\n response[/*status*/ 's'] as string,\n response[/* data */ 'd'] as string\n );\n }, Math.floor(0));\n }\n });\n }\n\n /**\n * @inheritDoc\n */\n put(\n pathString: string,\n data: unknown,\n onComplete?: (a: string, b: string) => void,\n hash?: string\n ) {\n this.putInternal('p', pathString, data, onComplete, hash);\n }\n\n /**\n * @inheritDoc\n */\n merge(\n pathString: string,\n data: unknown,\n onComplete: (a: string, b: string | null) => void,\n hash?: string\n ) {\n this.putInternal('m', pathString, data, onComplete, hash);\n }\n\n putInternal(\n action: string,\n pathString: string,\n data: unknown,\n onComplete: (a: string, b: string | null) => void,\n hash?: string\n ) {\n const request: { [k: string]: unknown } = {\n /*path*/ p: pathString,\n /*data*/ d: data\n };\n\n if (hash !== undefined) {\n request[/*hash*/ 'h'] = hash;\n }\n\n // TODO: Only keep track of the most recent put for a given path?\n this.outstandingPuts_.push({\n action,\n request,\n onComplete\n });\n\n this.outstandingPutCount_++;\n const index = this.outstandingPuts_.length - 1;\n\n if (this.connected_) {\n this.sendPut_(index);\n } else {\n this.log_('Buffering put: ' + pathString);\n }\n }\n\n private sendPut_(index: number) {\n const action = this.outstandingPuts_[index].action;\n const request = this.outstandingPuts_[index].request;\n const onComplete = this.outstandingPuts_[index].onComplete;\n this.outstandingPuts_[index].queued = this.connected_;\n\n this.sendRequest(action, request, (message: { [k: string]: unknown }) => {\n this.log_(action + ' response', message);\n\n delete this.outstandingPuts_[index];\n this.outstandingPutCount_--;\n\n // Clean up array occasionally.\n if (this.outstandingPutCount_ === 0) {\n this.outstandingPuts_ = [];\n }\n\n if (onComplete) {\n onComplete(\n message[/*status*/ 's'] as string,\n message[/* data */ 'd'] as string\n );\n }\n });\n }\n\n /**\n * @inheritDoc\n */\n reportStats(stats: { [k: string]: unknown }) {\n // If we're not connected, we just drop the stats.\n if (this.connected_) {\n const request = { /*counters*/ c: stats };\n this.log_('reportStats', request);\n\n this.sendRequest(/*stats*/ 's', request, result => {\n const status = result[/*status*/ 's'];\n if (status !== 'ok') {\n const errorReason = result[/* data */ 'd'];\n this.log_('reportStats', 'Error sending stats: ' + errorReason);\n }\n });\n }\n }\n\n private onDataMessage_(message: { [k: string]: unknown }) {\n if ('r' in message) {\n // this is a response\n this.log_('from server: ' + stringify(message));\n const reqNum = message['r'] as string;\n const onResponse = this.requestCBHash_[reqNum];\n if (onResponse) {\n delete this.requestCBHash_[reqNum];\n onResponse(message[/*body*/ 'b']);\n }\n } else if ('error' in message) {\n throw 'A server-side error has occurred: ' + message['error'];\n } else if ('a' in message) {\n // a and b are action and body, respectively\n this.onDataPush_(message['a'] as string, message['b'] as {});\n }\n }\n\n private onDataPush_(action: string, body: { [k: string]: unknown }) {\n this.log_('handleServerMessage', action, body);\n if (action === 'd') {\n this.onDataUpdate_(\n body[/*path*/ 'p'] as string,\n body[/*data*/ 'd'],\n /*isMerge*/ false,\n body['t'] as number\n );\n } else if (action === 'm') {\n this.onDataUpdate_(\n body[/*path*/ 'p'] as string,\n body[/*data*/ 'd'],\n /*isMerge=*/ true,\n body['t'] as number\n );\n } else if (action === 'c') {\n this.onListenRevoked_(\n body[/*path*/ 'p'] as string,\n body[/*query*/ 'q'] as unknown[]\n );\n } else if (action === 'ac') {\n this.onAuthRevoked_(\n body[/*status code*/ 's'] as string,\n body[/* explanation */ 'd'] as string\n );\n } else if (action === 'sd') {\n this.onSecurityDebugPacket_(body);\n } else {\n error(\n 'Unrecognized action received from server: ' +\n stringify(action) +\n '\\nAre you using the latest client?'\n );\n }\n }\n\n private onReady_(timestamp: number, sessionId: string) {\n this.log_('connection ready');\n this.connected_ = true;\n this.lastConnectionEstablishedTime_ = new Date().getTime();\n this.handleTimestamp_(timestamp);\n this.lastSessionId = sessionId;\n if (this.firstConnection_) {\n this.sendConnectStats_();\n }\n this.restoreState_();\n this.firstConnection_ = false;\n this.onConnectStatus_(true);\n }\n\n private scheduleConnect_(timeout: number) {\n assert(\n !this.realtime_,\n \"Scheduling a connect when we're already connected/ing?\"\n );\n\n if (this.establishConnectionTimer_) {\n clearTimeout(this.establishConnectionTimer_);\n }\n\n // NOTE: Even when timeout is 0, it's important to do a setTimeout to work around an infuriating \"Security Error\" in\n // Firefox when trying to write to our long-polling iframe in some scenarios (e.g. Forge or our unit tests).\n\n this.establishConnectionTimer_ = setTimeout(() => {\n this.establishConnectionTimer_ = null;\n this.establishConnection_();\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n }, Math.floor(timeout)) as any;\n }\n\n private onVisible_(visible: boolean) {\n // NOTE: Tabbing away and back to a window will defeat our reconnect backoff, but I think that's fine.\n if (\n visible &&\n !this.visible_ &&\n this.reconnectDelay_ === this.maxReconnectDelay_\n ) {\n this.log_('Window became visible. Reducing delay.');\n this.reconnectDelay_ = RECONNECT_MIN_DELAY;\n\n if (!this.realtime_) {\n this.scheduleConnect_(0);\n }\n }\n this.visible_ = visible;\n }\n\n private onOnline_(online: boolean) {\n if (online) {\n this.log_('Browser went online.');\n this.reconnectDelay_ = RECONNECT_MIN_DELAY;\n if (!this.realtime_) {\n this.scheduleConnect_(0);\n }\n } else {\n this.log_('Browser went offline. Killing connection.');\n if (this.realtime_) {\n this.realtime_.close();\n }\n }\n }\n\n private onRealtimeDisconnect_() {\n this.log_('data client disconnected');\n this.connected_ = false;\n this.realtime_ = null;\n\n // Since we don't know if our sent transactions succeeded or not, we need to cancel them.\n this.cancelSentTransactions_();\n\n // Clear out the pending requests.\n this.requestCBHash_ = {};\n\n if (this.shouldReconnect_()) {\n if (!this.visible_) {\n this.log_(\"Window isn't visible. Delaying reconnect.\");\n this.reconnectDelay_ = this.maxReconnectDelay_;\n this.lastConnectionAttemptTime_ = new Date().getTime();\n } else if (this.lastConnectionEstablishedTime_) {\n // If we've been connected long enough, reset reconnect delay to minimum.\n const timeSinceLastConnectSucceeded =\n new Date().getTime() - this.lastConnectionEstablishedTime_;\n if (timeSinceLastConnectSucceeded > RECONNECT_DELAY_RESET_TIMEOUT) {\n this.reconnectDelay_ = RECONNECT_MIN_DELAY;\n }\n this.lastConnectionEstablishedTime_ = null;\n }\n\n const timeSinceLastConnectAttempt =\n new Date().getTime() - this.lastConnectionAttemptTime_;\n let reconnectDelay = Math.max(\n 0,\n this.reconnectDelay_ - timeSinceLastConnectAttempt\n );\n reconnectDelay = Math.random() * reconnectDelay;\n\n this.log_('Trying to reconnect in ' + reconnectDelay + 'ms');\n this.scheduleConnect_(reconnectDelay);\n\n // Adjust reconnect delay for next time.\n this.reconnectDelay_ = Math.min(\n this.maxReconnectDelay_,\n this.reconnectDelay_ * RECONNECT_DELAY_MULTIPLIER\n );\n }\n this.onConnectStatus_(false);\n }\n\n private establishConnection_() {\n if (this.shouldReconnect_()) {\n this.log_('Making a connection attempt');\n this.lastConnectionAttemptTime_ = new Date().getTime();\n this.lastConnectionEstablishedTime_ = null;\n const onDataMessage = this.onDataMessage_.bind(this);\n const onReady = this.onReady_.bind(this);\n const onDisconnect = this.onRealtimeDisconnect_.bind(this);\n const connId = this.id + ':' + PersistentConnection.nextConnectionId_++;\n const self = this;\n const lastSessionId = this.lastSessionId;\n let canceled = false;\n let connection: Connection | null = null;\n const closeFn = function() {\n if (connection) {\n connection.close();\n } else {\n canceled = true;\n onDisconnect();\n }\n };\n const sendRequestFn = function(msg: object) {\n assert(\n connection,\n \"sendRequest call when we're not connected not allowed.\"\n );\n connection.sendRequest(msg);\n };\n\n this.realtime_ = {\n close: closeFn,\n sendRequest: sendRequestFn\n };\n\n const forceRefresh = this.forceTokenRefresh_;\n this.forceTokenRefresh_ = false;\n\n // First fetch auth token, and establish connection after fetching the token was successful\n this.authTokenProvider_\n .getToken(forceRefresh)\n .then(result => {\n if (!canceled) {\n log('getToken() completed. Creating connection.');\n self.authToken_ = result && result.accessToken;\n connection = new Connection(\n connId,\n self.repoInfo_,\n self.applicationId_,\n onDataMessage,\n onReady,\n onDisconnect,\n /* onKill= */ reason => {\n warn(reason + ' (' + self.repoInfo_.toString() + ')');\n self.interrupt(SERVER_KILL_INTERRUPT_REASON);\n },\n lastSessionId\n );\n } else {\n log('getToken() completed but was canceled');\n }\n })\n .then(null, error => {\n self.log_('Failed to get token: ' + error);\n if (!canceled) {\n if (CONSTANTS.NODE_ADMIN) {\n // This may be a critical error for the Admin Node.js SDK, so log a warning.\n // But getToken() may also just have temporarily failed, so we still want to\n // continue retrying.\n warn(error);\n }\n closeFn();\n }\n });\n }\n }\n\n interrupt(reason: string) {\n log('Interrupting connection for reason: ' + reason);\n this.interruptReasons_[reason] = true;\n if (this.realtime_) {\n this.realtime_.close();\n } else {\n if (this.establishConnectionTimer_) {\n clearTimeout(this.establishConnectionTimer_);\n this.establishConnectionTimer_ = null;\n }\n if (this.connected_) {\n this.onRealtimeDisconnect_();\n }\n }\n }\n\n resume(reason: string) {\n log('Resuming connection for reason: ' + reason);\n delete this.interruptReasons_[reason];\n if (isEmpty(this.interruptReasons_)) {\n this.reconnectDelay_ = RECONNECT_MIN_DELAY;\n if (!this.realtime_) {\n this.scheduleConnect_(0);\n }\n }\n }\n\n private handleTimestamp_(timestamp: number) {\n const delta = timestamp - new Date().getTime();\n this.onServerInfoUpdate_({ serverTimeOffset: delta });\n }\n\n private cancelSentTransactions_() {\n for (let i = 0; i < this.outstandingPuts_.length; i++) {\n const put = this.outstandingPuts_[i];\n if (put && /*hash*/ 'h' in put.request && put.queued) {\n if (put.onComplete) {\n put.onComplete('disconnect');\n }\n\n delete this.outstandingPuts_[i];\n this.outstandingPutCount_--;\n }\n }\n\n // Clean up array occasionally.\n if (this.outstandingPutCount_ === 0) {\n this.outstandingPuts_ = [];\n }\n }\n\n private onListenRevoked_(pathString: string, query?: unknown[]) {\n // Remove the listen and manufacture a \"permission_denied\" error for the failed listen.\n let queryId;\n if (!query) {\n queryId = 'default';\n } else {\n queryId = query.map(q => ObjectToUniqueKey(q)).join('$');\n }\n const listen = this.removeListen_(pathString, queryId);\n if (listen && listen.onComplete) {\n listen.onComplete('permission_denied');\n }\n }\n\n private removeListen_(pathString: string, queryId: string): ListenSpec {\n const normalizedPathString = new Path(pathString).toString(); // normalize path.\n let listen;\n if (this.listens.has(normalizedPathString)) {\n const map = this.listens.get(normalizedPathString)!;\n listen = map.get(queryId);\n map.delete(queryId);\n if (map.size === 0) {\n this.listens.delete(normalizedPathString);\n }\n } else {\n // all listens for this path has already been removed\n listen = undefined;\n }\n return listen;\n }\n\n private onAuthRevoked_(statusCode: string, explanation: string) {\n log('Auth token revoked: ' + statusCode + '/' + explanation);\n this.authToken_ = null;\n this.forceTokenRefresh_ = true;\n this.realtime_.close();\n if (statusCode === 'invalid_token' || statusCode === 'permission_denied') {\n // We'll wait a couple times before logging the warning / increasing the\n // retry period since oauth tokens will report as \"invalid\" if they're\n // just expired. Plus there may be transient issues that resolve themselves.\n this.invalidAuthTokenCount_++;\n if (this.invalidAuthTokenCount_ >= INVALID_AUTH_TOKEN_THRESHOLD) {\n // Set a long reconnect delay because recovery is unlikely\n this.reconnectDelay_ = RECONNECT_MAX_DELAY_FOR_ADMINS;\n\n // Notify the auth token provider that the token is invalid, which will log\n // a warning\n this.authTokenProvider_.notifyForInvalidToken();\n }\n }\n }\n\n private onSecurityDebugPacket_(body: { [k: string]: unknown }) {\n if (this.securityDebugCallback_) {\n this.securityDebugCallback_(body);\n } else {\n if ('msg' in body) {\n console.log(\n 'FIREBASE: ' + (body['msg'] as string).replace('\\n', '\\nFIREBASE: ')\n );\n }\n }\n }\n\n private restoreState_() {\n //Re-authenticate ourselves if we have a credential stored.\n this.tryAuth();\n\n // Puts depend on having received the corresponding data update from the server before they complete, so we must\n // make sure to send listens before puts.\n for (const queries of this.listens.values()) {\n for (const listenSpec of queries.values()) {\n this.sendListen_(listenSpec);\n }\n }\n\n for (let i = 0; i < this.outstandingPuts_.length; i++) {\n if (this.outstandingPuts_[i]) {\n this.sendPut_(i);\n }\n }\n\n while (this.onDisconnectRequestQueue_.length) {\n const request = this.onDisconnectRequestQueue_.shift();\n this.sendOnDisconnect_(\n request.action,\n request.pathString,\n request.data,\n request.onComplete\n );\n }\n }\n\n /**\n * Sends client stats for first connection\n */\n private sendConnectStats_() {\n const stats: { [k: string]: number } = {};\n\n let clientName = 'js';\n if (CONSTANTS.NODE_ADMIN) {\n clientName = 'admin_node';\n } else if (CONSTANTS.NODE_CLIENT) {\n clientName = 'node';\n }\n\n stats['sdk.' + clientName + '.' + SDK_VERSION.replace(/\\./g, '-')] = 1;\n\n if (isMobileCordova()) {\n stats['framework.cordova'] = 1;\n } else if (isReactNative()) {\n stats['framework.reactnative'] = 1;\n }\n this.reportStats(stats);\n }\n\n private shouldReconnect_(): boolean {\n const online = OnlineMonitor.getInstance().currentlyOnline();\n return isEmpty(this.interruptReasons_) && online;\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { assert, jsonEval, safeGet, querystring } from '@firebase/util';\nimport { logWrapper, warn } from './util/util';\n\nimport { ServerActions } from './ServerActions';\nimport { RepoInfo } from './RepoInfo';\nimport { AuthTokenProvider } from './AuthTokenProvider';\nimport { Query } from '../api/Query';\n\n/**\n * An implementation of ServerActions that communicates with the server via REST requests.\n * This is mostly useful for compatibility with crawlers, where we don't want to spin up a full\n * persistent connection (using WebSockets or long-polling)\n */\nexport class ReadonlyRestClient extends ServerActions {\n reportStats(stats: { [k: string]: unknown }): void {\n throw new Error('Method not implemented.');\n }\n\n /** @private {function(...[*])} */\n private log_: (...args: unknown[]) => void = logWrapper('p:rest:');\n\n /**\n * We don't actually need to track listens, except to prevent us calling an onComplete for a listen\n * that's been removed. :-/\n *\n * @private {!Object.}\n */\n private listens_: { [k: string]: object } = {};\n\n /**\n * @param {!Query} query\n * @param {?number=} tag\n * @return {string}\n * @private\n */\n static getListenId_(query: Query, tag?: number | null): string {\n if (tag !== undefined) {\n return 'tag$' + tag;\n } else {\n assert(\n query.getQueryParams().isDefault(),\n \"should have a tag if it's not a default query.\"\n );\n return query.path.toString();\n }\n }\n\n /**\n * @param {!RepoInfo} repoInfo_ Data about the namespace we are connecting to\n * @param {function(string, *, boolean, ?number)} onDataUpdate_ A callback for new data from the server\n * @param {AuthTokenProvider} authTokenProvider_\n * @implements {ServerActions}\n */\n constructor(\n private repoInfo_: RepoInfo,\n private onDataUpdate_: (\n a: string,\n b: unknown,\n c: boolean,\n d: number | null\n ) => void,\n private authTokenProvider_: AuthTokenProvider\n ) {\n super();\n }\n\n /** @inheritDoc */\n listen(\n query: Query,\n currentHashFn: () => string,\n tag: number | null,\n onComplete: (a: string, b: unknown) => void\n ) {\n const pathString = query.path.toString();\n this.log_(\n 'Listen called for ' + pathString + ' ' + query.queryIdentifier()\n );\n\n // Mark this listener so we can tell if it's removed.\n const listenId = ReadonlyRestClient.getListenId_(query, tag);\n const thisListen = {};\n this.listens_[listenId] = thisListen;\n\n const queryStringParameters = query\n .getQueryParams()\n .toRestQueryStringParameters();\n\n this.restRequest_(\n pathString + '.json',\n queryStringParameters,\n (error, result) => {\n let data = result;\n\n if (error === 404) {\n data = null;\n error = null;\n }\n\n if (error === null) {\n this.onDataUpdate_(pathString, data, /*isMerge=*/ false, tag);\n }\n\n if (safeGet(this.listens_, listenId) === thisListen) {\n let status;\n if (!error) {\n status = 'ok';\n } else if (error === 401) {\n status = 'permission_denied';\n } else {\n status = 'rest_error:' + error;\n }\n\n onComplete(status, null);\n }\n }\n );\n }\n\n /** @inheritDoc */\n unlisten(query: Query, tag: number | null) {\n const listenId = ReadonlyRestClient.getListenId_(query, tag);\n delete this.listens_[listenId];\n }\n\n /** @inheritDoc */\n refreshAuthToken(token: string) {\n // no-op since we just always call getToken.\n }\n\n /**\n * Performs a REST request to the given path, with the provided query string parameters,\n * and any auth credentials we have.\n *\n * @param {!string} pathString\n * @param {!Object.} queryStringParameters\n * @param {?function(?number, *=)} callback\n * @private\n */\n private restRequest_(\n pathString: string,\n queryStringParameters: { [k: string]: string | number } = {},\n callback: ((a: number | null, b?: unknown) => void) | null\n ) {\n queryStringParameters['format'] = 'export';\n\n this.authTokenProvider_\n .getToken(/*forceRefresh=*/ false)\n .then(authTokenData => {\n const authToken = authTokenData && authTokenData.accessToken;\n if (authToken) {\n queryStringParameters['auth'] = authToken;\n }\n\n const url =\n (this.repoInfo_.secure ? 'https://' : 'http://') +\n this.repoInfo_.host +\n pathString +\n '?' +\n 'ns=' +\n this.repoInfo_.namespace +\n querystring(queryStringParameters);\n\n this.log_('Sending REST request for ' + url);\n const xhr = new XMLHttpRequest();\n xhr.onreadystatechange = () => {\n if (callback && xhr.readyState === 4) {\n this.log_(\n 'REST Response for ' + url + ' received. status:',\n xhr.status,\n 'response:',\n xhr.responseText\n );\n let res = null;\n if (xhr.status >= 200 && xhr.status < 300) {\n try {\n res = jsonEval(xhr.responseText);\n } catch (e) {\n warn(\n 'Failed to parse JSON response for ' +\n url +\n ': ' +\n xhr.responseText\n );\n }\n callback(null, res);\n } else {\n // 401 and 404 are expected.\n if (xhr.status !== 401 && xhr.status !== 404) {\n warn(\n 'Got unsuccessful REST response for ' +\n url +\n ' Status: ' +\n xhr.status\n );\n }\n callback(xhr.status);\n }\n callback = null;\n }\n };\n\n xhr.open('GET', url, /*asynchronous=*/ true);\n xhr.send();\n });\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport {\n generateWithValues,\n resolveDeferredValueSnapshot,\n resolveDeferredValueTree\n} from './util/ServerValues';\nimport { nodeFromJSON } from './snap/nodeFromJSON';\nimport { Path } from './util/Path';\nimport { SparseSnapshotTree } from './SparseSnapshotTree';\nimport { SyncTree } from './SyncTree';\nimport { SnapshotHolder } from './SnapshotHolder';\nimport { stringify, map, isEmpty } from '@firebase/util';\nimport { beingCrawled, each, exceptionGuard, warn, log } from './util/util';\n\nimport { AuthTokenProvider } from './AuthTokenProvider';\nimport { StatsManager } from './stats/StatsManager';\nimport { StatsReporter } from './stats/StatsReporter';\nimport { StatsListener } from './stats/StatsListener';\nimport { EventQueue } from './view/EventQueue';\nimport { PersistentConnection } from './PersistentConnection';\nimport { ReadonlyRestClient } from './ReadonlyRestClient';\nimport { FirebaseApp } from '@firebase/app-types';\nimport { RepoInfo } from './RepoInfo';\nimport { Database } from '../api/Database';\nimport { ServerActions } from './ServerActions';\nimport { Query } from '../api/Query';\nimport { EventRegistration } from './view/EventRegistration';\nimport { StatsCollection } from './stats/StatsCollection';\nimport { Event } from './view/Event';\nimport { Node } from './snap/Node';\nimport { FirebaseAuthInternalName } from '@firebase/auth-interop-types';\nimport { Provider } from '@firebase/component';\nimport { Indexable } from './util/misc';\n\nconst INTERRUPT_REASON = 'repo_interrupt';\n\n/**\n * A connection to a single data repository.\n */\nexport class Repo {\n dataUpdateCount = 0;\n private infoSyncTree_: SyncTree;\n private serverSyncTree_: SyncTree;\n\n private stats_: StatsCollection;\n private statsListener_: StatsListener | null = null;\n private eventQueue_ = new EventQueue();\n private nextWriteId_ = 1;\n private server_: ServerActions;\n private statsReporter_: StatsReporter;\n private transactionsInit_: () => void;\n private infoData_: SnapshotHolder;\n private abortTransactions_: (path: Path) => Path;\n private rerunTransactions_: (changedPath: Path) => Path;\n private interceptServerDataCallback_:\n | ((a: string, b: unknown) => void)\n | null = null;\n private __database: Database;\n\n /** A list of data pieces and paths to be set when this client disconnects. */\n private onDisconnect_ = new SparseSnapshotTree();\n\n // TODO: This should be @private but it's used by test_access.js and internal.js\n persistentConnection_: PersistentConnection | null = null;\n\n constructor(\n public repoInfo_: RepoInfo,\n forceRestClient: boolean,\n public app: FirebaseApp,\n authProvider: Provider\n ) {\n const authTokenProvider = new AuthTokenProvider(app, authProvider);\n\n this.stats_ = StatsManager.getCollection(repoInfo_);\n\n if (forceRestClient || beingCrawled()) {\n this.server_ = new ReadonlyRestClient(\n this.repoInfo_,\n this.onDataUpdate_.bind(this),\n authTokenProvider\n );\n\n // Minor hack: Fire onConnect immediately, since there's no actual connection.\n setTimeout(this.onConnectStatus_.bind(this, true), 0);\n } else {\n const authOverride = app.options['databaseAuthVariableOverride'];\n // Validate authOverride\n if (typeof authOverride !== 'undefined' && authOverride !== null) {\n if (typeof authOverride !== 'object') {\n throw new Error(\n 'Only objects are supported for option databaseAuthVariableOverride'\n );\n }\n try {\n stringify(authOverride);\n } catch (e) {\n throw new Error('Invalid authOverride provided: ' + e);\n }\n }\n\n this.persistentConnection_ = new PersistentConnection(\n this.repoInfo_,\n app.options.appId,\n this.onDataUpdate_.bind(this),\n this.onConnectStatus_.bind(this),\n this.onServerInfoUpdate_.bind(this),\n authTokenProvider,\n authOverride\n );\n\n this.server_ = this.persistentConnection_;\n }\n\n authTokenProvider.addTokenChangeListener(token => {\n this.server_.refreshAuthToken(token);\n });\n\n // In the case of multiple Repos for the same repoInfo (i.e. there are multiple Firebase.Contexts being used),\n // we only want to create one StatsReporter. As such, we'll report stats over the first Repo created.\n this.statsReporter_ = StatsManager.getOrCreateReporter(\n repoInfo_,\n () => new StatsReporter(this.stats_, this.server_)\n );\n\n this.transactionsInit_();\n\n // Used for .info.\n this.infoData_ = new SnapshotHolder();\n this.infoSyncTree_ = new SyncTree({\n startListening: (query, tag, currentHashFn, onComplete) => {\n let infoEvents: Event[] = [];\n const node = this.infoData_.getNode(query.path);\n // This is possibly a hack, but we have different semantics for .info endpoints. We don't raise null events\n // on initial data...\n if (!node.isEmpty()) {\n infoEvents = this.infoSyncTree_.applyServerOverwrite(\n query.path,\n node\n );\n setTimeout(() => {\n onComplete('ok');\n }, 0);\n }\n return infoEvents;\n },\n stopListening: () => {}\n });\n this.updateInfo_('connected', false);\n\n this.serverSyncTree_ = new SyncTree({\n startListening: (query, tag, currentHashFn, onComplete) => {\n this.server_.listen(query, currentHashFn, tag, (status, data) => {\n const events = onComplete(status, data);\n this.eventQueue_.raiseEventsForChangedPath(query.path, events);\n });\n // No synchronous events for network-backed sync trees\n return [];\n },\n stopListening: (query, tag) => {\n this.server_.unlisten(query, tag);\n }\n });\n }\n\n /**\n * @return The URL corresponding to the root of this Firebase.\n */\n toString(): string {\n return (\n (this.repoInfo_.secure ? 'https://' : 'http://') + this.repoInfo_.host\n );\n }\n\n /**\n * @return The namespace represented by the repo.\n */\n name(): string {\n return this.repoInfo_.namespace;\n }\n\n /**\n * @return The time in milliseconds, taking the server offset into account if we have one.\n */\n serverTime(): number {\n const offsetNode = this.infoData_.getNode(\n new Path('.info/serverTimeOffset')\n );\n const offset = (offsetNode.val() as number) || 0;\n return new Date().getTime() + offset;\n }\n\n /**\n * Generate ServerValues using some variables from the repo object.\n */\n generateServerValues(): Indexable {\n return generateWithValues({\n timestamp: this.serverTime()\n });\n }\n\n /**\n * Called by realtime when we get new messages from the server.\n */\n private onDataUpdate_(\n pathString: string,\n data: unknown,\n isMerge: boolean,\n tag: number | null\n ) {\n // For testing.\n this.dataUpdateCount++;\n const path = new Path(pathString);\n data = this.interceptServerDataCallback_\n ? this.interceptServerDataCallback_(pathString, data)\n : data;\n let events = [];\n if (tag) {\n if (isMerge) {\n const taggedChildren = map(\n data as { [k: string]: unknown },\n (raw: unknown) => nodeFromJSON(raw)\n );\n events = this.serverSyncTree_.applyTaggedQueryMerge(\n path,\n taggedChildren,\n tag\n );\n } else {\n const taggedSnap = nodeFromJSON(data);\n events = this.serverSyncTree_.applyTaggedQueryOverwrite(\n path,\n taggedSnap,\n tag\n );\n }\n } else if (isMerge) {\n const changedChildren = map(\n data as { [k: string]: unknown },\n (raw: unknown) => nodeFromJSON(raw)\n );\n events = this.serverSyncTree_.applyServerMerge(path, changedChildren);\n } else {\n const snap = nodeFromJSON(data);\n events = this.serverSyncTree_.applyServerOverwrite(path, snap);\n }\n let affectedPath = path;\n if (events.length > 0) {\n // Since we have a listener outstanding for each transaction, receiving any events\n // is a proxy for some change having occurred.\n affectedPath = this.rerunTransactions_(path);\n }\n this.eventQueue_.raiseEventsForChangedPath(affectedPath, events);\n }\n\n // TODO: This should be @private but it's used by test_access.js and internal.js\n interceptServerData_(callback: ((a: string, b: unknown) => unknown) | null) {\n this.interceptServerDataCallback_ = callback;\n }\n\n private onConnectStatus_(connectStatus: boolean) {\n this.updateInfo_('connected', connectStatus);\n if (connectStatus === false) {\n this.runOnDisconnectEvents_();\n }\n }\n\n private onServerInfoUpdate_(updates: object) {\n each(updates, (key: string, value: unknown) => {\n this.updateInfo_(key, value);\n });\n }\n\n private updateInfo_(pathString: string, value: unknown) {\n const path = new Path('/.info/' + pathString);\n const newNode = nodeFromJSON(value);\n this.infoData_.updateSnapshot(path, newNode);\n const events = this.infoSyncTree_.applyServerOverwrite(path, newNode);\n this.eventQueue_.raiseEventsForChangedPath(path, events);\n }\n\n private getNextWriteId_(): number {\n return this.nextWriteId_++;\n }\n\n setWithPriority(\n path: Path,\n newVal: unknown,\n newPriority: number | string | null,\n onComplete: ((status: Error | null, errorReason?: string) => void) | null\n ) {\n this.log_('set', {\n path: path.toString(),\n value: newVal,\n priority: newPriority\n });\n\n // TODO: Optimize this behavior to either (a) store flag to skip resolving where possible and / or\n // (b) store unresolved paths on JSON parse\n const serverValues = this.generateServerValues();\n const newNodeUnresolved = nodeFromJSON(newVal, newPriority);\n const existing = this.serverSyncTree_.calcCompleteEventCache(path);\n const newNode = resolveDeferredValueSnapshot(\n newNodeUnresolved,\n existing,\n serverValues\n );\n\n const writeId = this.getNextWriteId_();\n const events = this.serverSyncTree_.applyUserOverwrite(\n path,\n newNode,\n writeId,\n true\n );\n this.eventQueue_.queueEvents(events);\n this.server_.put(\n path.toString(),\n newNodeUnresolved.val(/*export=*/ true),\n (status, errorReason) => {\n const success = status === 'ok';\n if (!success) {\n warn('set at ' + path + ' failed: ' + status);\n }\n\n const clearEvents = this.serverSyncTree_.ackUserWrite(\n writeId,\n !success\n );\n this.eventQueue_.raiseEventsForChangedPath(path, clearEvents);\n this.callOnCompleteCallback(onComplete, status, errorReason);\n }\n );\n const affectedPath = this.abortTransactions_(path);\n this.rerunTransactions_(affectedPath);\n // We queued the events above, so just flush the queue here\n this.eventQueue_.raiseEventsForChangedPath(affectedPath, []);\n }\n\n update(\n path: Path,\n childrenToMerge: { [k: string]: unknown },\n onComplete: ((status: Error | null, errorReason?: string) => void) | null\n ) {\n this.log_('update', { path: path.toString(), value: childrenToMerge });\n\n // Start with our existing data and merge each child into it.\n let empty = true;\n const serverValues = this.generateServerValues();\n const changedChildren: { [k: string]: Node } = {};\n each(childrenToMerge, (changedKey: string, changedValue: unknown) => {\n empty = false;\n changedChildren[changedKey] = resolveDeferredValueTree(\n path.child(changedKey),\n nodeFromJSON(changedValue),\n this.serverSyncTree_,\n serverValues\n );\n });\n\n if (!empty) {\n const writeId = this.getNextWriteId_();\n const events = this.serverSyncTree_.applyUserMerge(\n path,\n changedChildren,\n writeId\n );\n this.eventQueue_.queueEvents(events);\n this.server_.merge(\n path.toString(),\n childrenToMerge,\n (status, errorReason) => {\n const success = status === 'ok';\n if (!success) {\n warn('update at ' + path + ' failed: ' + status);\n }\n\n const clearEvents = this.serverSyncTree_.ackUserWrite(\n writeId,\n !success\n );\n const affectedPath =\n clearEvents.length > 0 ? this.rerunTransactions_(path) : path;\n this.eventQueue_.raiseEventsForChangedPath(affectedPath, clearEvents);\n this.callOnCompleteCallback(onComplete, status, errorReason);\n }\n );\n\n each(childrenToMerge, (changedPath: string) => {\n const affectedPath = this.abortTransactions_(path.child(changedPath));\n this.rerunTransactions_(affectedPath);\n });\n\n // We queued the events above, so just flush the queue here\n this.eventQueue_.raiseEventsForChangedPath(path, []);\n } else {\n log(\"update() called with empty data. Don't do anything.\");\n this.callOnCompleteCallback(onComplete, 'ok');\n }\n }\n\n /**\n * Applies all of the changes stored up in the onDisconnect_ tree.\n */\n private runOnDisconnectEvents_() {\n this.log_('onDisconnectEvents');\n\n const serverValues = this.generateServerValues();\n const resolvedOnDisconnectTree = new SparseSnapshotTree();\n this.onDisconnect_.forEachTree(Path.Empty, (path, node) => {\n const resolved = resolveDeferredValueTree(\n path,\n node,\n this.serverSyncTree_,\n serverValues\n );\n resolvedOnDisconnectTree.remember(path, resolved);\n });\n let events: Event[] = [];\n\n resolvedOnDisconnectTree.forEachTree(Path.Empty, (path, snap) => {\n events = events.concat(\n this.serverSyncTree_.applyServerOverwrite(path, snap)\n );\n const affectedPath = this.abortTransactions_(path);\n this.rerunTransactions_(affectedPath);\n });\n\n this.onDisconnect_ = new SparseSnapshotTree();\n this.eventQueue_.raiseEventsForChangedPath(Path.Empty, events);\n }\n\n onDisconnectCancel(\n path: Path,\n onComplete: ((status: Error | null, errorReason?: string) => void) | null\n ) {\n this.server_.onDisconnectCancel(path.toString(), (status, errorReason) => {\n if (status === 'ok') {\n this.onDisconnect_.forget(path);\n }\n this.callOnCompleteCallback(onComplete, status, errorReason);\n });\n }\n\n onDisconnectSet(\n path: Path,\n value: unknown,\n onComplete: ((status: Error | null, errorReason?: string) => void) | null\n ) {\n const newNode = nodeFromJSON(value);\n this.server_.onDisconnectPut(\n path.toString(),\n newNode.val(/*export=*/ true),\n (status, errorReason) => {\n if (status === 'ok') {\n this.onDisconnect_.remember(path, newNode);\n }\n this.callOnCompleteCallback(onComplete, status, errorReason);\n }\n );\n }\n\n onDisconnectSetWithPriority(\n path: Path,\n value: unknown,\n priority: unknown,\n onComplete: ((status: Error | null, errorReason?: string) => void) | null\n ) {\n const newNode = nodeFromJSON(value, priority);\n this.server_.onDisconnectPut(\n path.toString(),\n newNode.val(/*export=*/ true),\n (status, errorReason) => {\n if (status === 'ok') {\n this.onDisconnect_.remember(path, newNode);\n }\n this.callOnCompleteCallback(onComplete, status, errorReason);\n }\n );\n }\n\n onDisconnectUpdate(\n path: Path,\n childrenToMerge: { [k: string]: unknown },\n onComplete: ((status: Error | null, errorReason?: string) => void) | null\n ) {\n if (isEmpty(childrenToMerge)) {\n log(\n \"onDisconnect().update() called with empty data. Don't do anything.\"\n );\n this.callOnCompleteCallback(onComplete, 'ok');\n return;\n }\n\n this.server_.onDisconnectMerge(\n path.toString(),\n childrenToMerge,\n (status, errorReason) => {\n if (status === 'ok') {\n each(childrenToMerge, (childName: string, childNode: unknown) => {\n const newChildNode = nodeFromJSON(childNode);\n this.onDisconnect_.remember(path.child(childName), newChildNode);\n });\n }\n this.callOnCompleteCallback(onComplete, status, errorReason);\n }\n );\n }\n\n addEventCallbackForQuery(query: Query, eventRegistration: EventRegistration) {\n let events;\n if (query.path.getFront() === '.info') {\n events = this.infoSyncTree_.addEventRegistration(\n query,\n eventRegistration\n );\n } else {\n events = this.serverSyncTree_.addEventRegistration(\n query,\n eventRegistration\n );\n }\n this.eventQueue_.raiseEventsAtPath(query.path, events);\n }\n\n removeEventCallbackForQuery(\n query: Query,\n eventRegistration: EventRegistration\n ) {\n // These are guaranteed not to raise events, since we're not passing in a cancelError. However, we can future-proof\n // a little bit by handling the return values anyways.\n let events;\n if (query.path.getFront() === '.info') {\n events = this.infoSyncTree_.removeEventRegistration(\n query,\n eventRegistration\n );\n } else {\n events = this.serverSyncTree_.removeEventRegistration(\n query,\n eventRegistration\n );\n }\n this.eventQueue_.raiseEventsAtPath(query.path, events);\n }\n\n interrupt() {\n if (this.persistentConnection_) {\n this.persistentConnection_.interrupt(INTERRUPT_REASON);\n }\n }\n\n resume() {\n if (this.persistentConnection_) {\n this.persistentConnection_.resume(INTERRUPT_REASON);\n }\n }\n\n stats(showDelta: boolean = false) {\n if (typeof console === 'undefined') {\n return;\n }\n\n let stats: { [k: string]: unknown };\n if (showDelta) {\n if (!this.statsListener_) {\n this.statsListener_ = new StatsListener(this.stats_);\n }\n stats = this.statsListener_.get();\n } else {\n stats = this.stats_.get();\n }\n\n const longestName = Object.keys(stats).reduce(\n (previousValue, currentValue) =>\n Math.max(currentValue.length, previousValue),\n 0\n );\n\n each(stats, (stat: string, value: unknown) => {\n let paddedStat = stat;\n // pad stat names to be the same length (plus 2 extra spaces).\n for (let i = stat.length; i < longestName + 2; i++) {\n paddedStat += ' ';\n }\n console.log(paddedStat + value);\n });\n }\n\n statsIncrementCounter(metric: string) {\n this.stats_.incrementCounter(metric);\n this.statsReporter_.includeStat(metric);\n }\n\n private log_(...varArgs: unknown[]) {\n let prefix = '';\n if (this.persistentConnection_) {\n prefix = this.persistentConnection_.id + ':';\n }\n log(prefix, ...varArgs);\n }\n\n callOnCompleteCallback(\n callback: ((status: Error | null, errorReason?: string) => void) | null,\n status: string,\n errorReason?: string | null\n ) {\n if (callback) {\n exceptionGuard(() => {\n if (status === 'ok') {\n callback(null);\n } else {\n const code = (status || 'error').toUpperCase();\n let message = code;\n if (errorReason) {\n message += ': ' + errorReason;\n }\n\n const error = new Error(message);\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n (error as any).code = code;\n callback(error);\n }\n });\n }\n }\n\n get database(): Database {\n return this.__database || (this.__database = new Database(this));\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { IndexedFilter } from './IndexedFilter';\nimport { PRIORITY_INDEX } from '../../snap/indexes/PriorityIndex';\nimport { NamedNode, Node } from '../../../core/snap/Node';\nimport { ChildrenNode } from '../../snap/ChildrenNode';\nimport { NodeFilter } from './NodeFilter';\nimport { QueryParams } from '../QueryParams';\nimport { Index } from '../../snap/indexes/Index';\nimport { Path } from '../../util/Path';\nimport { CompleteChildSource } from '../CompleteChildSource';\nimport { ChildChangeAccumulator } from '../ChildChangeAccumulator';\n\n/**\n * Filters nodes by range and uses an IndexFilter to track any changes after filtering the node\n *\n * @constructor\n * @implements {NodeFilter}\n */\nexport class RangedFilter implements NodeFilter {\n /**\n * @type {!IndexedFilter}\n * @const\n * @private\n */\n private indexedFilter_: IndexedFilter;\n\n /**\n * @const\n * @type {!Index}\n * @private\n */\n private index_: Index;\n\n /**\n * @const\n * @type {!NamedNode}\n * @private\n */\n private startPost_: NamedNode;\n\n /**\n * @const\n * @type {!NamedNode}\n * @private\n */\n private endPost_: NamedNode;\n\n /**\n * @param {!QueryParams} params\n */\n constructor(params: QueryParams) {\n this.indexedFilter_ = new IndexedFilter(params.getIndex());\n this.index_ = params.getIndex();\n this.startPost_ = RangedFilter.getStartPost_(params);\n this.endPost_ = RangedFilter.getEndPost_(params);\n }\n\n /**\n * @return {!NamedNode}\n */\n getStartPost(): NamedNode {\n return this.startPost_;\n }\n\n /**\n * @return {!NamedNode}\n */\n getEndPost(): NamedNode {\n return this.endPost_;\n }\n\n /**\n * @param {!NamedNode} node\n * @return {boolean}\n */\n matches(node: NamedNode): boolean {\n return (\n this.index_.compare(this.getStartPost(), node) <= 0 &&\n this.index_.compare(node, this.getEndPost()) <= 0\n );\n }\n\n /**\n * @inheritDoc\n */\n updateChild(\n snap: Node,\n key: string,\n newChild: Node,\n affectedPath: Path,\n source: CompleteChildSource,\n optChangeAccumulator: ChildChangeAccumulator | null\n ): Node {\n if (!this.matches(new NamedNode(key, newChild))) {\n newChild = ChildrenNode.EMPTY_NODE;\n }\n return this.indexedFilter_.updateChild(\n snap,\n key,\n newChild,\n affectedPath,\n source,\n optChangeAccumulator\n );\n }\n\n /**\n * @inheritDoc\n */\n updateFullNode(\n oldSnap: Node,\n newSnap: Node,\n optChangeAccumulator: ChildChangeAccumulator | null\n ): Node {\n if (newSnap.isLeafNode()) {\n // Make sure we have a children node with the correct index, not a leaf node;\n newSnap = ChildrenNode.EMPTY_NODE;\n }\n let filtered = newSnap.withIndex(this.index_);\n // Don't support priorities on queries\n filtered = filtered.updatePriority(ChildrenNode.EMPTY_NODE);\n const self = this;\n newSnap.forEachChild(PRIORITY_INDEX, (key, childNode) => {\n if (!self.matches(new NamedNode(key, childNode))) {\n filtered = filtered.updateImmediateChild(key, ChildrenNode.EMPTY_NODE);\n }\n });\n return this.indexedFilter_.updateFullNode(\n oldSnap,\n filtered,\n optChangeAccumulator\n );\n }\n\n /**\n * @inheritDoc\n */\n updatePriority(oldSnap: Node, newPriority: Node): Node {\n // Don't support priorities on queries\n return oldSnap;\n }\n\n /**\n * @inheritDoc\n */\n filtersNodes(): boolean {\n return true;\n }\n\n /**\n * @inheritDoc\n */\n getIndexedFilter(): IndexedFilter {\n return this.indexedFilter_;\n }\n\n /**\n * @inheritDoc\n */\n getIndex(): Index {\n return this.index_;\n }\n\n /**\n * @param {!QueryParams} params\n * @return {!NamedNode}\n * @private\n */\n private static getStartPost_(params: QueryParams): NamedNode {\n if (params.hasStart()) {\n const startName = params.getIndexStartName();\n return params.getIndex().makePost(params.getIndexStartValue(), startName);\n } else {\n return params.getIndex().minPost();\n }\n }\n\n /**\n * @param {!QueryParams} params\n * @return {!NamedNode}\n * @private\n */\n private static getEndPost_(params: QueryParams): NamedNode {\n if (params.hasEnd()) {\n const endName = params.getIndexEndName();\n return params.getIndex().makePost(params.getIndexEndValue(), endName);\n } else {\n return params.getIndex().maxPost();\n }\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { RangedFilter } from './RangedFilter';\nimport { ChildrenNode } from '../../snap/ChildrenNode';\nimport { Node, NamedNode } from '../../snap/Node';\nimport { assert } from '@firebase/util';\nimport { Change } from '../Change';\nimport { NodeFilter } from './NodeFilter';\nimport { Index } from '../../snap/indexes/Index';\nimport { IndexedFilter } from './IndexedFilter';\nimport { QueryParams } from '../QueryParams';\nimport { Path } from '../../util/Path';\nimport { CompleteChildSource } from '../CompleteChildSource';\nimport { ChildChangeAccumulator } from '../ChildChangeAccumulator';\n\n/**\n * Applies a limit and a range to a node and uses RangedFilter to do the heavy lifting where possible\n *\n * @constructor\n * @implements {NodeFilter}\n */\nexport class LimitedFilter implements NodeFilter {\n /**\n * @const\n * @type {RangedFilter}\n * @private\n */\n private readonly rangedFilter_: RangedFilter;\n\n /**\n * @const\n * @type {!Index}\n * @private\n */\n private readonly index_: Index;\n\n /**\n * @const\n * @type {number}\n * @private\n */\n private readonly limit_: number;\n\n /**\n * @const\n * @type {boolean}\n * @private\n */\n private readonly reverse_: boolean;\n\n /**\n * @param {!QueryParams} params\n */\n constructor(params: QueryParams) {\n this.rangedFilter_ = new RangedFilter(params);\n this.index_ = params.getIndex();\n this.limit_ = params.getLimit();\n this.reverse_ = !params.isViewFromLeft();\n }\n\n /**\n * @inheritDoc\n */\n updateChild(\n snap: Node,\n key: string,\n newChild: Node,\n affectedPath: Path,\n source: CompleteChildSource,\n optChangeAccumulator: ChildChangeAccumulator | null\n ): Node {\n if (!this.rangedFilter_.matches(new NamedNode(key, newChild))) {\n newChild = ChildrenNode.EMPTY_NODE;\n }\n if (snap.getImmediateChild(key).equals(newChild)) {\n // No change\n return snap;\n } else if (snap.numChildren() < this.limit_) {\n return this.rangedFilter_\n .getIndexedFilter()\n .updateChild(\n snap,\n key,\n newChild,\n affectedPath,\n source,\n optChangeAccumulator\n );\n } else {\n return this.fullLimitUpdateChild_(\n snap,\n key,\n newChild,\n source,\n optChangeAccumulator\n );\n }\n }\n\n /**\n * @inheritDoc\n */\n updateFullNode(\n oldSnap: Node,\n newSnap: Node,\n optChangeAccumulator: ChildChangeAccumulator | null\n ): Node {\n let filtered;\n if (newSnap.isLeafNode() || newSnap.isEmpty()) {\n // Make sure we have a children node with the correct index, not a leaf node;\n filtered = ChildrenNode.EMPTY_NODE.withIndex(this.index_);\n } else {\n if (\n this.limit_ * 2 < newSnap.numChildren() &&\n newSnap.isIndexed(this.index_)\n ) {\n // Easier to build up a snapshot, since what we're given has more than twice the elements we want\n filtered = ChildrenNode.EMPTY_NODE.withIndex(this.index_);\n // anchor to the startPost, endPost, or last element as appropriate\n let iterator;\n if (this.reverse_) {\n iterator = (newSnap as ChildrenNode).getReverseIteratorFrom(\n this.rangedFilter_.getEndPost(),\n this.index_\n );\n } else {\n iterator = (newSnap as ChildrenNode).getIteratorFrom(\n this.rangedFilter_.getStartPost(),\n this.index_\n );\n }\n let count = 0;\n while (iterator.hasNext() && count < this.limit_) {\n const next = iterator.getNext();\n let inRange;\n if (this.reverse_) {\n inRange =\n this.index_.compare(this.rangedFilter_.getStartPost(), next) <= 0;\n } else {\n inRange =\n this.index_.compare(next, this.rangedFilter_.getEndPost()) <= 0;\n }\n if (inRange) {\n filtered = filtered.updateImmediateChild(next.name, next.node);\n count++;\n } else {\n // if we have reached the end post, we cannot keep adding elemments\n break;\n }\n }\n } else {\n // The snap contains less than twice the limit. Faster to delete from the snap than build up a new one\n filtered = newSnap.withIndex(this.index_);\n // Don't support priorities on queries\n filtered = filtered.updatePriority(\n ChildrenNode.EMPTY_NODE\n ) as ChildrenNode;\n let startPost;\n let endPost;\n let cmp;\n let iterator;\n if (this.reverse_) {\n iterator = filtered.getReverseIterator(this.index_);\n startPost = this.rangedFilter_.getEndPost();\n endPost = this.rangedFilter_.getStartPost();\n const indexCompare = this.index_.getCompare();\n cmp = (a: NamedNode, b: NamedNode) => indexCompare(b, a);\n } else {\n iterator = filtered.getIterator(this.index_);\n startPost = this.rangedFilter_.getStartPost();\n endPost = this.rangedFilter_.getEndPost();\n cmp = this.index_.getCompare();\n }\n\n let count = 0;\n let foundStartPost = false;\n while (iterator.hasNext()) {\n const next = iterator.getNext();\n if (!foundStartPost && cmp(startPost, next) <= 0) {\n // start adding\n foundStartPost = true;\n }\n const inRange =\n foundStartPost && count < this.limit_ && cmp(next, endPost) <= 0;\n if (inRange) {\n count++;\n } else {\n filtered = filtered.updateImmediateChild(\n next.name,\n ChildrenNode.EMPTY_NODE\n );\n }\n }\n }\n }\n return this.rangedFilter_\n .getIndexedFilter()\n .updateFullNode(oldSnap, filtered, optChangeAccumulator);\n }\n\n /**\n * @inheritDoc\n */\n updatePriority(oldSnap: Node, newPriority: Node): Node {\n // Don't support priorities on queries\n return oldSnap;\n }\n\n /**\n * @inheritDoc\n */\n filtersNodes(): boolean {\n return true;\n }\n\n /**\n * @inheritDoc\n */\n getIndexedFilter(): IndexedFilter {\n return this.rangedFilter_.getIndexedFilter();\n }\n\n /**\n * @inheritDoc\n */\n getIndex(): Index {\n return this.index_;\n }\n\n /**\n * @param {!Node} snap\n * @param {string} childKey\n * @param {!Node} childSnap\n * @param {!CompleteChildSource} source\n * @param {?ChildChangeAccumulator} changeAccumulator\n * @return {!Node}\n * @private\n */\n private fullLimitUpdateChild_(\n snap: Node,\n childKey: string,\n childSnap: Node,\n source: CompleteChildSource,\n changeAccumulator: ChildChangeAccumulator | null\n ): Node {\n // TODO: rename all cache stuff etc to general snap terminology\n let cmp;\n if (this.reverse_) {\n const indexCmp = this.index_.getCompare();\n cmp = (a: NamedNode, b: NamedNode) => indexCmp(b, a);\n } else {\n cmp = this.index_.getCompare();\n }\n const oldEventCache = snap as ChildrenNode;\n assert(oldEventCache.numChildren() === this.limit_, '');\n const newChildNamedNode = new NamedNode(childKey, childSnap);\n const windowBoundary = this.reverse_\n ? oldEventCache.getFirstChild(this.index_)\n : (oldEventCache.getLastChild(this.index_) as NamedNode);\n const inRange = this.rangedFilter_.matches(newChildNamedNode);\n if (oldEventCache.hasChild(childKey)) {\n const oldChildSnap = oldEventCache.getImmediateChild(childKey);\n let nextChild = source.getChildAfterChild(\n this.index_,\n windowBoundary,\n this.reverse_\n );\n while (\n nextChild != null &&\n (nextChild.name === childKey || oldEventCache.hasChild(nextChild.name))\n ) {\n // There is a weird edge case where a node is updated as part of a merge in the write tree, but hasn't\n // been applied to the limited filter yet. Ignore this next child which will be updated later in\n // the limited filter...\n nextChild = source.getChildAfterChild(\n this.index_,\n nextChild,\n this.reverse_\n );\n }\n const compareNext =\n nextChild == null ? 1 : cmp(nextChild, newChildNamedNode);\n const remainsInWindow =\n inRange && !childSnap.isEmpty() && compareNext >= 0;\n if (remainsInWindow) {\n if (changeAccumulator != null) {\n changeAccumulator.trackChildChange(\n Change.childChangedChange(childKey, childSnap, oldChildSnap)\n );\n }\n return oldEventCache.updateImmediateChild(childKey, childSnap);\n } else {\n if (changeAccumulator != null) {\n changeAccumulator.trackChildChange(\n Change.childRemovedChange(childKey, oldChildSnap)\n );\n }\n const newEventCache = oldEventCache.updateImmediateChild(\n childKey,\n ChildrenNode.EMPTY_NODE\n );\n const nextChildInRange =\n nextChild != null && this.rangedFilter_.matches(nextChild);\n if (nextChildInRange) {\n if (changeAccumulator != null) {\n changeAccumulator.trackChildChange(\n Change.childAddedChange(nextChild.name, nextChild.node)\n );\n }\n return newEventCache.updateImmediateChild(\n nextChild.name,\n nextChild.node\n );\n } else {\n return newEventCache;\n }\n }\n } else if (childSnap.isEmpty()) {\n // we're deleting a node, but it was not in the window, so ignore it\n return snap;\n } else if (inRange) {\n if (cmp(windowBoundary, newChildNamedNode) >= 0) {\n if (changeAccumulator != null) {\n changeAccumulator.trackChildChange(\n Change.childRemovedChange(windowBoundary.name, windowBoundary.node)\n );\n changeAccumulator.trackChildChange(\n Change.childAddedChange(childKey, childSnap)\n );\n }\n return oldEventCache\n .updateImmediateChild(childKey, childSnap)\n .updateImmediateChild(windowBoundary.name, ChildrenNode.EMPTY_NODE);\n } else {\n return snap;\n }\n } else {\n return snap;\n }\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { assert, stringify } from '@firebase/util';\nimport { MIN_NAME, MAX_NAME } from '../util/util';\nimport { KEY_INDEX } from '../snap/indexes/KeyIndex';\nimport { PRIORITY_INDEX } from '../snap/indexes/PriorityIndex';\nimport { VALUE_INDEX } from '../snap/indexes/ValueIndex';\nimport { PathIndex } from '../snap/indexes/PathIndex';\nimport { IndexedFilter } from './filter/IndexedFilter';\nimport { LimitedFilter } from './filter/LimitedFilter';\nimport { RangedFilter } from './filter/RangedFilter';\nimport { NodeFilter } from './filter/NodeFilter';\nimport { Index } from '../snap/indexes/Index';\n\n/**\n * This class is an immutable-from-the-public-api struct containing a set of query parameters defining a\n * range to be returned for a particular location. It is assumed that validation of parameters is done at the\n * user-facing API level, so it is not done here.\n * @constructor\n */\nexport class QueryParams {\n private limitSet_ = false;\n private startSet_ = false;\n private startNameSet_ = false;\n private endSet_ = false;\n private endNameSet_ = false;\n\n private limit_ = 0;\n private viewFrom_ = '';\n private indexStartValue_: unknown | null = null;\n private indexStartName_ = '';\n private indexEndValue_: unknown | null = null;\n private indexEndName_ = '';\n\n private index_ = PRIORITY_INDEX;\n\n /**\n * Wire Protocol Constants\n * @const\n * @enum {string}\n * @private\n */\n private static readonly WIRE_PROTOCOL_CONSTANTS_ = {\n INDEX_START_VALUE: 'sp',\n INDEX_START_NAME: 'sn',\n INDEX_END_VALUE: 'ep',\n INDEX_END_NAME: 'en',\n LIMIT: 'l',\n VIEW_FROM: 'vf',\n VIEW_FROM_LEFT: 'l',\n VIEW_FROM_RIGHT: 'r',\n INDEX: 'i'\n };\n\n /**\n * REST Query Constants\n * @const\n * @enum {string}\n * @private\n */\n private static readonly REST_QUERY_CONSTANTS_ = {\n ORDER_BY: 'orderBy',\n PRIORITY_INDEX: '$priority',\n VALUE_INDEX: '$value',\n KEY_INDEX: '$key',\n START_AT: 'startAt',\n END_AT: 'endAt',\n LIMIT_TO_FIRST: 'limitToFirst',\n LIMIT_TO_LAST: 'limitToLast'\n };\n\n /**\n * Default, empty query parameters\n * @type {!QueryParams}\n * @const\n */\n static readonly DEFAULT = new QueryParams();\n\n /**\n * @return {boolean}\n */\n hasStart(): boolean {\n return this.startSet_;\n }\n\n /**\n * @return {boolean} True if it would return from left.\n */\n isViewFromLeft(): boolean {\n if (this.viewFrom_ === '') {\n // limit(), rather than limitToFirst or limitToLast was called.\n // This means that only one of startSet_ and endSet_ is true. Use them\n // to calculate which side of the view to anchor to. If neither is set,\n // anchor to the end.\n return this.startSet_;\n } else {\n return (\n this.viewFrom_ === QueryParams.WIRE_PROTOCOL_CONSTANTS_.VIEW_FROM_LEFT\n );\n }\n }\n\n /**\n * Only valid to call if hasStart() returns true\n * @return {*}\n */\n getIndexStartValue(): unknown {\n assert(this.startSet_, 'Only valid if start has been set');\n return this.indexStartValue_;\n }\n\n /**\n * Only valid to call if hasStart() returns true.\n * Returns the starting key name for the range defined by these query parameters\n * @return {!string}\n */\n getIndexStartName(): string {\n assert(this.startSet_, 'Only valid if start has been set');\n if (this.startNameSet_) {\n return this.indexStartName_;\n } else {\n return MIN_NAME;\n }\n }\n\n /**\n * @return {boolean}\n */\n hasEnd(): boolean {\n return this.endSet_;\n }\n\n /**\n * Only valid to call if hasEnd() returns true.\n * @return {*}\n */\n getIndexEndValue(): unknown {\n assert(this.endSet_, 'Only valid if end has been set');\n return this.indexEndValue_;\n }\n\n /**\n * Only valid to call if hasEnd() returns true.\n * Returns the end key name for the range defined by these query parameters\n * @return {!string}\n */\n getIndexEndName(): string {\n assert(this.endSet_, 'Only valid if end has been set');\n if (this.endNameSet_) {\n return this.indexEndName_;\n } else {\n return MAX_NAME;\n }\n }\n\n /**\n * @return {boolean}\n */\n hasLimit(): boolean {\n return this.limitSet_;\n }\n\n /**\n * @return {boolean} True if a limit has been set and it has been explicitly anchored\n */\n hasAnchoredLimit(): boolean {\n return this.limitSet_ && this.viewFrom_ !== '';\n }\n\n /**\n * Only valid to call if hasLimit() returns true\n * @return {!number}\n */\n getLimit(): number {\n assert(this.limitSet_, 'Only valid if limit has been set');\n return this.limit_;\n }\n\n /**\n * @return {!Index}\n */\n getIndex(): Index {\n return this.index_;\n }\n\n /**\n * @return {!QueryParams}\n * @private\n */\n private copy_(): QueryParams {\n const copy = new QueryParams();\n copy.limitSet_ = this.limitSet_;\n copy.limit_ = this.limit_;\n copy.startSet_ = this.startSet_;\n copy.indexStartValue_ = this.indexStartValue_;\n copy.startNameSet_ = this.startNameSet_;\n copy.indexStartName_ = this.indexStartName_;\n copy.endSet_ = this.endSet_;\n copy.indexEndValue_ = this.indexEndValue_;\n copy.endNameSet_ = this.endNameSet_;\n copy.indexEndName_ = this.indexEndName_;\n copy.index_ = this.index_;\n copy.viewFrom_ = this.viewFrom_;\n return copy;\n }\n\n /**\n * @param {!number} newLimit\n * @return {!QueryParams}\n */\n limit(newLimit: number): QueryParams {\n const newParams = this.copy_();\n newParams.limitSet_ = true;\n newParams.limit_ = newLimit;\n newParams.viewFrom_ = '';\n return newParams;\n }\n\n /**\n * @param {!number} newLimit\n * @return {!QueryParams}\n */\n limitToFirst(newLimit: number): QueryParams {\n const newParams = this.copy_();\n newParams.limitSet_ = true;\n newParams.limit_ = newLimit;\n newParams.viewFrom_ = QueryParams.WIRE_PROTOCOL_CONSTANTS_.VIEW_FROM_LEFT;\n return newParams;\n }\n\n /**\n * @param {!number} newLimit\n * @return {!QueryParams}\n */\n limitToLast(newLimit: number): QueryParams {\n const newParams = this.copy_();\n newParams.limitSet_ = true;\n newParams.limit_ = newLimit;\n newParams.viewFrom_ = QueryParams.WIRE_PROTOCOL_CONSTANTS_.VIEW_FROM_RIGHT;\n return newParams;\n }\n\n /**\n * @param {*} indexValue\n * @param {?string=} key\n * @return {!QueryParams}\n */\n startAt(indexValue: unknown, key?: string | null): QueryParams {\n const newParams = this.copy_();\n newParams.startSet_ = true;\n if (indexValue === undefined) {\n indexValue = null;\n }\n newParams.indexStartValue_ = indexValue;\n if (key != null) {\n newParams.startNameSet_ = true;\n newParams.indexStartName_ = key;\n } else {\n newParams.startNameSet_ = false;\n newParams.indexStartName_ = '';\n }\n return newParams;\n }\n\n /**\n * @param {*} indexValue\n * @param {?string=} key\n * @return {!QueryParams}\n */\n endAt(indexValue: unknown, key?: string | null): QueryParams {\n const newParams = this.copy_();\n newParams.endSet_ = true;\n if (indexValue === undefined) {\n indexValue = null;\n }\n newParams.indexEndValue_ = indexValue;\n if (key !== undefined) {\n newParams.endNameSet_ = true;\n newParams.indexEndName_ = key;\n } else {\n newParams.endNameSet_ = false;\n newParams.indexEndName_ = '';\n }\n return newParams;\n }\n\n /**\n * @param {!Index} index\n * @return {!QueryParams}\n */\n orderBy(index: Index): QueryParams {\n const newParams = this.copy_();\n newParams.index_ = index;\n return newParams;\n }\n\n /**\n * @return {!Object}\n */\n getQueryObject(): {} {\n const WIRE_PROTOCOL_CONSTANTS = QueryParams.WIRE_PROTOCOL_CONSTANTS_;\n const obj: { [k: string]: unknown } = {};\n if (this.startSet_) {\n obj[WIRE_PROTOCOL_CONSTANTS.INDEX_START_VALUE] = this.indexStartValue_;\n if (this.startNameSet_) {\n obj[WIRE_PROTOCOL_CONSTANTS.INDEX_START_NAME] = this.indexStartName_;\n }\n }\n if (this.endSet_) {\n obj[WIRE_PROTOCOL_CONSTANTS.INDEX_END_VALUE] = this.indexEndValue_;\n if (this.endNameSet_) {\n obj[WIRE_PROTOCOL_CONSTANTS.INDEX_END_NAME] = this.indexEndName_;\n }\n }\n if (this.limitSet_) {\n obj[WIRE_PROTOCOL_CONSTANTS.LIMIT] = this.limit_;\n let viewFrom = this.viewFrom_;\n if (viewFrom === '') {\n if (this.isViewFromLeft()) {\n viewFrom = WIRE_PROTOCOL_CONSTANTS.VIEW_FROM_LEFT;\n } else {\n viewFrom = WIRE_PROTOCOL_CONSTANTS.VIEW_FROM_RIGHT;\n }\n }\n obj[WIRE_PROTOCOL_CONSTANTS.VIEW_FROM] = viewFrom;\n }\n // For now, priority index is the default, so we only specify if it's some other index\n if (this.index_ !== PRIORITY_INDEX) {\n obj[WIRE_PROTOCOL_CONSTANTS.INDEX] = this.index_.toString();\n }\n return obj;\n }\n\n /**\n * @return {boolean}\n */\n loadsAllData(): boolean {\n return !(this.startSet_ || this.endSet_ || this.limitSet_);\n }\n\n /**\n * @return {boolean}\n */\n isDefault(): boolean {\n return this.loadsAllData() && this.index_ === PRIORITY_INDEX;\n }\n\n /**\n * @return {!NodeFilter}\n */\n getNodeFilter(): NodeFilter {\n if (this.loadsAllData()) {\n return new IndexedFilter(this.getIndex());\n } else if (this.hasLimit()) {\n return new LimitedFilter(this);\n } else {\n return new RangedFilter(this);\n }\n }\n\n /**\n * Returns a set of REST query string parameters representing this query.\n *\n * @return {!Object.} query string parameters\n */\n toRestQueryStringParameters(): { [k: string]: string | number } {\n const REST_CONSTANTS = QueryParams.REST_QUERY_CONSTANTS_;\n const qs: { [k: string]: string | number } = {};\n\n if (this.isDefault()) {\n return qs;\n }\n\n let orderBy;\n if (this.index_ === PRIORITY_INDEX) {\n orderBy = REST_CONSTANTS.PRIORITY_INDEX;\n } else if (this.index_ === VALUE_INDEX) {\n orderBy = REST_CONSTANTS.VALUE_INDEX;\n } else if (this.index_ === KEY_INDEX) {\n orderBy = REST_CONSTANTS.KEY_INDEX;\n } else {\n assert(this.index_ instanceof PathIndex, 'Unrecognized index type!');\n orderBy = this.index_.toString();\n }\n qs[REST_CONSTANTS.ORDER_BY] = stringify(orderBy);\n\n if (this.startSet_) {\n qs[REST_CONSTANTS.START_AT] = stringify(this.indexStartValue_);\n if (this.startNameSet_) {\n qs[REST_CONSTANTS.START_AT] += ',' + stringify(this.indexStartName_);\n }\n }\n\n if (this.endSet_) {\n qs[REST_CONSTANTS.END_AT] = stringify(this.indexEndValue_);\n if (this.endNameSet_) {\n qs[REST_CONSTANTS.END_AT] += ',' + stringify(this.indexEndName_);\n }\n }\n\n if (this.limitSet_) {\n if (this.isViewFromLeft()) {\n qs[REST_CONSTANTS.LIMIT_TO_FIRST] = this.limit_;\n } else {\n qs[REST_CONSTANTS.LIMIT_TO_LAST] = this.limit_;\n }\n }\n\n return qs;\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { OnDisconnect } from './onDisconnect';\nimport { TransactionResult } from './TransactionResult';\nimport { warn } from '../core/util/util';\nimport { nextPushId } from '../core/util/NextPushId';\nimport { Query } from './Query';\nimport { Repo } from '../core/Repo';\nimport { Path } from '../core/util/Path';\nimport { QueryParams } from '../core/view/QueryParams';\nimport {\n validateRootPathString,\n validatePathString,\n validateFirebaseMergeDataArg,\n validateBoolean,\n validatePriority,\n validateFirebaseDataArg,\n validateWritablePath\n} from '../core/util/validation';\nimport { validateArgCount, validateCallback, Deferred } from '@firebase/util';\n\nimport { SyncPoint } from '../core/SyncPoint';\nimport { Database } from './Database';\nimport { DataSnapshot } from './DataSnapshot';\nimport * as types from '@firebase/database-types';\n\nexport interface ReferenceConstructor {\n new (repo: Repo, path: Path): Reference;\n}\n\nexport class Reference extends Query {\n then: Promise['then'];\n catch: Promise['catch'];\n\n /**\n * Call options:\n * new Reference(Repo, Path) or\n * new Reference(url: string, string|RepoManager)\n *\n * Externally - this is the firebase.database.Reference type.\n *\n * @param {!Repo} repo\n * @param {(!Path)} path\n * @extends {Query}\n */\n constructor(repo: Repo, path: Path) {\n if (!(repo instanceof Repo)) {\n throw new Error(\n 'new Reference() no longer supported - use app.database().'\n );\n }\n\n // call Query's constructor, passing in the repo and path.\n super(repo, path, QueryParams.DEFAULT, false);\n }\n\n /** @return {?string} */\n getKey(): string | null {\n validateArgCount('Reference.key', 0, 0, arguments.length);\n\n if (this.path.isEmpty()) {\n return null;\n } else {\n return this.path.getBack();\n }\n }\n\n /**\n * @param {!(string|Path)} pathString\n * @return {!Reference}\n */\n child(pathString: string | Path): Reference {\n validateArgCount('Reference.child', 1, 1, arguments.length);\n if (typeof pathString === 'number') {\n pathString = String(pathString);\n } else if (!(pathString instanceof Path)) {\n if (this.path.getFront() === null) {\n validateRootPathString('Reference.child', 1, pathString, false);\n } else {\n validatePathString('Reference.child', 1, pathString, false);\n }\n }\n\n return new Reference(this.repo, this.path.child(pathString));\n }\n\n /** @return {?Reference} */\n getParent(): Reference | null {\n validateArgCount('Reference.parent', 0, 0, arguments.length);\n\n const parentPath = this.path.parent();\n return parentPath === null ? null : new Reference(this.repo, parentPath);\n }\n\n /** @return {!Reference} */\n getRoot(): Reference {\n validateArgCount('Reference.root', 0, 0, arguments.length);\n\n let ref: Reference = this;\n while (ref.getParent() !== null) {\n ref = ref.getParent();\n }\n return ref;\n }\n\n /** @return {!Database} */\n databaseProp(): Database {\n return this.repo.database;\n }\n\n /**\n * @param {*} newVal\n * @param {function(?Error)=} onComplete\n * @return {!Promise}\n */\n set(\n newVal: unknown,\n onComplete?: (a: Error | null) => void\n ): Promise {\n validateArgCount('Reference.set', 1, 2, arguments.length);\n validateWritablePath('Reference.set', this.path);\n validateFirebaseDataArg('Reference.set', 1, newVal, this.path, false);\n validateCallback('Reference.set', 2, onComplete, true);\n\n const deferred = new Deferred();\n this.repo.setWithPriority(\n this.path,\n newVal,\n /*priority=*/ null,\n deferred.wrapCallback(onComplete)\n );\n return deferred.promise;\n }\n\n /**\n * @param {!Object} objectToMerge\n * @param {function(?Error)=} onComplete\n * @return {!Promise}\n */\n update(\n objectToMerge: object,\n onComplete?: (a: Error | null) => void\n ): Promise {\n validateArgCount('Reference.update', 1, 2, arguments.length);\n validateWritablePath('Reference.update', this.path);\n\n if (Array.isArray(objectToMerge)) {\n const newObjectToMerge: { [k: string]: unknown } = {};\n for (let i = 0; i < objectToMerge.length; ++i) {\n newObjectToMerge['' + i] = objectToMerge[i];\n }\n objectToMerge = newObjectToMerge;\n warn(\n 'Passing an Array to Firebase.update() is deprecated. ' +\n 'Use set() if you want to overwrite the existing data, or ' +\n 'an Object with integer keys if you really do want to ' +\n 'only update some of the children.'\n );\n }\n validateFirebaseMergeDataArg(\n 'Reference.update',\n 1,\n objectToMerge,\n this.path,\n false\n );\n validateCallback('Reference.update', 2, onComplete, true);\n const deferred = new Deferred();\n this.repo.update(\n this.path,\n objectToMerge as { [k: string]: unknown },\n deferred.wrapCallback(onComplete)\n );\n return deferred.promise;\n }\n\n /**\n * @param {*} newVal\n * @param {string|number|null} newPriority\n * @param {function(?Error)=} onComplete\n * @return {!Promise}\n */\n setWithPriority(\n newVal: unknown,\n newPriority: string | number | null,\n onComplete?: (a: Error | null) => void\n ): Promise {\n validateArgCount('Reference.setWithPriority', 2, 3, arguments.length);\n validateWritablePath('Reference.setWithPriority', this.path);\n validateFirebaseDataArg(\n 'Reference.setWithPriority',\n 1,\n newVal,\n this.path,\n false\n );\n validatePriority('Reference.setWithPriority', 2, newPriority, false);\n validateCallback('Reference.setWithPriority', 3, onComplete, true);\n\n if (this.getKey() === '.length' || this.getKey() === '.keys') {\n throw 'Reference.setWithPriority failed: ' +\n this.getKey() +\n ' is a read-only object.';\n }\n\n const deferred = new Deferred();\n this.repo.setWithPriority(\n this.path,\n newVal,\n newPriority,\n deferred.wrapCallback(onComplete)\n );\n return deferred.promise;\n }\n\n /**\n * @param {function(?Error)=} onComplete\n * @return {!Promise}\n */\n remove(onComplete?: (a: Error | null) => void): Promise {\n validateArgCount('Reference.remove', 0, 1, arguments.length);\n validateWritablePath('Reference.remove', this.path);\n validateCallback('Reference.remove', 1, onComplete, true);\n\n return this.set(null, onComplete);\n }\n\n /**\n * @param {function(*):*} transactionUpdate\n * @param {(function(?Error, boolean, ?DataSnapshot))=} onComplete\n * @param {boolean=} applyLocally\n * @return {!Promise}\n */\n transaction(\n transactionUpdate: (a: unknown) => unknown,\n onComplete?: (a: Error | null, b: boolean, c: DataSnapshot | null) => void,\n applyLocally?: boolean\n ): Promise {\n validateArgCount('Reference.transaction', 1, 3, arguments.length);\n validateWritablePath('Reference.transaction', this.path);\n validateCallback('Reference.transaction', 1, transactionUpdate, false);\n validateCallback('Reference.transaction', 2, onComplete, true);\n // NOTE: applyLocally is an internal-only option for now. We need to decide if we want to keep it and how\n // to expose it.\n validateBoolean('Reference.transaction', 3, applyLocally, true);\n\n if (this.getKey() === '.length' || this.getKey() === '.keys') {\n throw 'Reference.transaction failed: ' +\n this.getKey() +\n ' is a read-only object.';\n }\n\n if (applyLocally === undefined) {\n applyLocally = true;\n }\n\n const deferred = new Deferred();\n if (typeof onComplete === 'function') {\n deferred.promise.catch(() => {});\n }\n\n const promiseComplete = function(\n error: Error,\n committed: boolean,\n snapshot: DataSnapshot\n ) {\n if (error) {\n deferred.reject(error);\n } else {\n deferred.resolve(new TransactionResult(committed, snapshot));\n }\n if (typeof onComplete === 'function') {\n onComplete(error, committed, snapshot);\n }\n };\n this.repo.startTransaction(\n this.path,\n transactionUpdate,\n promiseComplete,\n applyLocally\n );\n\n return deferred.promise;\n }\n\n /**\n * @param {string|number|null} priority\n * @param {function(?Error)=} onComplete\n * @return {!Promise}\n */\n setPriority(\n priority: string | number | null,\n onComplete?: (a: Error | null) => void\n ): Promise {\n validateArgCount('Reference.setPriority', 1, 2, arguments.length);\n validateWritablePath('Reference.setPriority', this.path);\n validatePriority('Reference.setPriority', 1, priority, false);\n validateCallback('Reference.setPriority', 2, onComplete, true);\n\n const deferred = new Deferred();\n this.repo.setWithPriority(\n this.path.child('.priority'),\n priority,\n null,\n deferred.wrapCallback(onComplete)\n );\n return deferred.promise;\n }\n\n /**\n * @param {*=} value\n * @param {function(?Error)=} onComplete\n * @return {!Reference}\n */\n push(value?: unknown, onComplete?: (a: Error | null) => void): Reference {\n validateArgCount('Reference.push', 0, 2, arguments.length);\n validateWritablePath('Reference.push', this.path);\n validateFirebaseDataArg('Reference.push', 1, value, this.path, true);\n validateCallback('Reference.push', 2, onComplete, true);\n\n const now = this.repo.serverTime();\n const name = nextPushId(now);\n\n // push() returns a ThennableReference whose promise is fulfilled with a regular Reference.\n // We use child() to create handles to two different references. The first is turned into a\n // ThennableReference below by adding then() and catch() methods and is used as the\n // return value of push(). The second remains a regular Reference and is used as the fulfilled\n // value of the first ThennableReference.\n const thennablePushRef = this.child(name);\n const pushRef = this.child(name);\n\n let promise;\n if (value != null) {\n promise = thennablePushRef.set(value, onComplete).then(() => pushRef);\n } else {\n promise = Promise.resolve(pushRef);\n }\n\n thennablePushRef.then = promise.then.bind(promise);\n thennablePushRef.catch = promise.then.bind(promise, undefined);\n\n if (typeof onComplete === 'function') {\n promise.catch(() => {});\n }\n\n return thennablePushRef;\n }\n\n /**\n * @return {!OnDisconnect}\n */\n onDisconnect(): OnDisconnect {\n validateWritablePath('Reference.onDisconnect', this.path);\n return new OnDisconnect(this.repo, this.path);\n }\n\n get database(): Database {\n return this.databaseProp();\n }\n\n get key(): string | null {\n return this.getKey();\n }\n\n get parent(): Reference | null {\n return this.getParent();\n }\n\n get root(): Reference {\n return this.getRoot();\n }\n}\n\n/**\n * Define reference constructor in various modules\n *\n * We are doing this here to avoid several circular\n * dependency issues\n */\nQuery.__referenceConstructor = Reference;\nSyncPoint.__referenceConstructor = Reference;\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { assert, contains, safeGet } from '@firebase/util';\nimport { Path } from './Path';\n\nimport { each } from './util';\n\n/**\n * Node in a Tree.\n */\nexport class TreeNode {\n // TODO: Consider making accessors that create children and value lazily or\n // separate Internal / Leaf 'types'.\n children: { [name: string]: TreeNode } = {};\n childCount = 0;\n value: T | null = null;\n}\n\n/**\n * A light-weight tree, traversable by path. Nodes can have both values and children.\n * Nodes are not enumerated (by forEachChild) unless they have a value or non-empty\n * children.\n */\nexport class Tree {\n /**\n * @template T\n * @param {string=} name_ Optional name of the node.\n * @param {Tree=} parent_ Optional parent node.\n * @param {TreeNode=} node_ Optional node to wrap.\n */\n constructor(\n private name_: string = '',\n private parent_: Tree | null = null,\n private node_: TreeNode = new TreeNode()\n ) {}\n\n /**\n * Returns a sub-Tree for the given path.\n *\n * @param {!(string|Path)} pathObj Path to look up.\n * @return {!Tree.} Tree for path.\n */\n subTree(pathObj: string | Path): Tree {\n // TODO: Require pathObj to be Path?\n let path = pathObj instanceof Path ? pathObj : new Path(pathObj);\n let child = this as Tree,\n next = path.getFront();\n while (next !== null) {\n const childNode = safeGet(child.node_.children, next) || new TreeNode();\n child = new Tree(next, child, childNode);\n path = path.popFront();\n next = path.getFront();\n }\n\n return child;\n }\n\n /**\n * Returns the data associated with this tree node.\n *\n * @return {?T} The data or null if no data exists.\n */\n getValue(): T | null {\n return this.node_.value;\n }\n\n /**\n * Sets data to this tree node.\n *\n * @param {!T} value Value to set.\n */\n setValue(value: T) {\n assert(typeof value !== 'undefined', 'Cannot set value to undefined');\n this.node_.value = value;\n this.updateParents_();\n }\n\n /**\n * Clears the contents of the tree node (its value and all children).\n */\n clear() {\n this.node_.value = null;\n this.node_.children = {};\n this.node_.childCount = 0;\n this.updateParents_();\n }\n\n /**\n * @return {boolean} Whether the tree has any children.\n */\n hasChildren(): boolean {\n return this.node_.childCount > 0;\n }\n\n /**\n * @return {boolean} Whether the tree is empty (no value or children).\n */\n isEmpty(): boolean {\n return this.getValue() === null && !this.hasChildren();\n }\n\n /**\n * Calls action for each child of this tree node.\n *\n * @param {function(!Tree.)} action Action to be called for each child.\n */\n forEachChild(action: (tree: Tree) => void) {\n each(this.node_.children, (child: string, childTree: TreeNode) => {\n action(new Tree(child, this, childTree));\n });\n }\n\n /**\n * Does a depth-first traversal of this node's descendants, calling action for each one.\n *\n * @param {function(!Tree.)} action Action to be called for each child.\n * @param {boolean=} includeSelf Whether to call action on this node as well. Defaults to\n * false.\n * @param {boolean=} childrenFirst Whether to call action on children before calling it on\n * parent.\n */\n forEachDescendant(\n action: (tree: Tree) => void,\n includeSelf?: boolean,\n childrenFirst?: boolean\n ) {\n if (includeSelf && !childrenFirst) {\n action(this);\n }\n\n this.forEachChild(child => {\n child.forEachDescendant(action, /*includeSelf=*/ true, childrenFirst);\n });\n\n if (includeSelf && childrenFirst) {\n action(this);\n }\n }\n\n /**\n * Calls action on each ancestor node.\n *\n * @param {function(!Tree.)} action Action to be called on each parent; return\n * true to abort.\n * @param {boolean=} includeSelf Whether to call action on this node as well.\n * @return {boolean} true if the action callback returned true.\n */\n forEachAncestor(\n action: (tree: Tree) => unknown,\n includeSelf?: boolean\n ): boolean {\n let node = includeSelf ? this : this.parent();\n while (node !== null) {\n if (action(node)) {\n return true;\n }\n node = node.parent();\n }\n return false;\n }\n\n /**\n * Does a depth-first traversal of this node's descendants. When a descendant with a value\n * is found, action is called on it and traversal does not continue inside the node.\n * Action is *not* called on this node.\n *\n * @param {function(!Tree.)} action Action to be called for each child.\n */\n forEachImmediateDescendantWithValue(action: (tree: Tree) => void) {\n this.forEachChild(child => {\n if (child.getValue() !== null) {\n action(child);\n } else {\n child.forEachImmediateDescendantWithValue(action);\n }\n });\n }\n\n /**\n * @return {!Path} The path of this tree node, as a Path.\n */\n path(): Path {\n return new Path(\n this.parent_ === null\n ? this.name_\n : this.parent_.path() + '/' + this.name_\n );\n }\n\n /**\n * @return {string} The name of the tree node.\n */\n name(): string {\n return this.name_;\n }\n\n /**\n * @return {?Tree} The parent tree node, or null if this is the root of the tree.\n */\n parent(): Tree | null {\n return this.parent_;\n }\n\n /**\n * Adds or removes this child from its parent based on whether it's empty or not.\n *\n * @private\n */\n private updateParents_() {\n if (this.parent_ !== null) {\n this.parent_.updateChild_(this.name_, this);\n }\n }\n\n /**\n * Adds or removes the passed child to this tree node, depending on whether it's empty.\n *\n * @param {string} childName The name of the child to update.\n * @param {!Tree.} child The child to update.\n * @private\n */\n private updateChild_(childName: string, child: Tree) {\n const childEmpty = child.isEmpty();\n const childExists = contains(this.node_.children, childName);\n if (childEmpty && childExists) {\n delete this.node_.children[childName];\n this.node_.childCount--;\n this.updateParents_();\n } else if (!childEmpty && !childExists) {\n this.node_.children[childName] = child.node_;\n this.node_.childCount++;\n this.updateParents_();\n }\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { assert, contains, safeGet } from '@firebase/util';\nimport { Reference } from '../api/Reference';\nimport { DataSnapshot } from '../api/DataSnapshot';\nimport { Path } from './util/Path';\nimport { Tree } from './util/Tree';\nimport { PRIORITY_INDEX } from './snap/indexes/PriorityIndex';\nimport { Node } from './snap/Node';\nimport { LUIDGenerator, warn, exceptionGuard } from './util/util';\nimport { resolveDeferredValueSnapshot } from './util/ServerValues';\nimport { isValidPriority, validateFirebaseData } from './util/validation';\n\nimport { nodeFromJSON } from './snap/nodeFromJSON';\nimport { ChildrenNode } from './snap/ChildrenNode';\nimport { Repo } from './Repo';\nimport { Event } from './view/Event';\n\n// TODO: This is pretty messy. Ideally, a lot of this would move into FirebaseData, or a transaction-specific\n// component used by FirebaseData, but it has ties to user callbacks (transaction update and onComplete) as well\n// as the realtime connection (to send transactions to the server). So that all needs to be decoupled first.\n// For now it's part of Repo, but in its own file.\n\n/**\n * @enum {number}\n */\nexport enum TransactionStatus {\n // We've run the transaction and updated transactionResultData_ with the result, but it isn't currently sent to the\n // server. A transaction will go from RUN -> SENT -> RUN if it comes back from the server as rejected due to\n // mismatched hash.\n RUN,\n\n // We've run the transaction and sent it to the server and it's currently outstanding (hasn't come back as accepted\n // or rejected yet).\n SENT,\n\n // Temporary state used to mark completed transactions (whether successful or aborted). The transaction will be\n // removed when we get a chance to prune completed ones.\n COMPLETED,\n\n // Used when an already-sent transaction needs to be aborted (e.g. due to a conflicting set() call that was made).\n // If it comes back as unsuccessful, we'll abort it.\n SENT_NEEDS_ABORT,\n\n // Temporary state used to mark transactions that need to be aborted.\n NEEDS_ABORT\n}\n\n/**\n * If a transaction does not succeed after 25 retries, we abort it. Among other things this ensure that if there's\n * ever a bug causing a mismatch between client / server hashes for some data, we won't retry indefinitely.\n * @type {number}\n * @const\n * @private\n */\n// eslint-disable-next-line @typescript-eslint/no-explicit-any\n(Repo as any).MAX_TRANSACTION_RETRIES_ = 25;\n\n/**\n * @typedef {{\n * path: !Path,\n * update: function(*):*,\n * onComplete: ?function(?Error, boolean, ?DataSnapshot),\n * status: ?TransactionStatus,\n * order: !number,\n * applyLocally: boolean,\n * retryCount: !number,\n * unwatcher: function(),\n * abortReason: ?string,\n * currentWriteId: !number,\n * currentInputSnapshot: ?Node,\n * currentOutputSnapshotRaw: ?Node,\n * currentOutputSnapshotResolved: ?Node\n * }}\n */\ninterface Transaction {\n path: Path;\n update: (a: unknown) => unknown;\n onComplete: (a: Error | null, b: boolean, c: DataSnapshot | null) => void;\n status: TransactionStatus;\n order: number;\n applyLocally: boolean;\n retryCount: number;\n unwatcher: () => void;\n abortReason: string | null;\n currentWriteId: number;\n currentInputSnapshot: Node | null;\n currentOutputSnapshotRaw: Node | null;\n currentOutputSnapshotResolved: Node | null;\n}\n\n/**\n * Setup the transaction data structures\n * @private\n */\n// eslint-disable-next-line @typescript-eslint/no-explicit-any\n(Repo.prototype as any).transactionsInit_ = function() {\n /**\n * Stores queues of outstanding transactions for Firebase locations.\n *\n * @type {!Tree.>}\n * @private\n */\n this.transactionQueueTree_ = new Tree();\n};\n\ndeclare module './Repo' {\n interface Repo {\n startTransaction(\n path: Path,\n transactionUpdate: (a: unknown) => void,\n onComplete: ((a: Error, b: boolean, c: DataSnapshot) => void) | null,\n applyLocally: boolean\n ): void;\n }\n}\n\n/**\n * Creates a new transaction, adds it to the transactions we're tracking, and sends it to the server if possible.\n *\n * @param {!Path} path Path at which to do transaction.\n * @param {function(*):*} transactionUpdate Update callback.\n * @param {?function(?Error, boolean, ?DataSnapshot)} onComplete Completion callback.\n * @param {boolean} applyLocally Whether or not to make intermediate results visible\n */\nRepo.prototype.startTransaction = function(\n path: Path,\n transactionUpdate: (a: unknown) => unknown,\n onComplete: ((a: Error, b: boolean, c: DataSnapshot) => void) | null,\n applyLocally: boolean\n) {\n this.log_('transaction on ' + path);\n\n // Add a watch to make sure we get server updates.\n const valueCallback = function() {};\n const watchRef = new Reference(this, path);\n watchRef.on('value', valueCallback);\n const unwatcher = function() {\n watchRef.off('value', valueCallback);\n };\n\n // Initialize transaction.\n const transaction: Transaction = {\n path,\n update: transactionUpdate,\n onComplete,\n\n // One of TransactionStatus enums.\n status: null,\n\n // Used when combining transactions at different locations to figure out which one goes first.\n order: LUIDGenerator(),\n\n // Whether to raise local events for this transaction.\n applyLocally,\n\n // Count of how many times we've retried the transaction.\n retryCount: 0,\n\n // Function to call to clean up our .on() listener.\n unwatcher,\n\n // Stores why a transaction was aborted.\n abortReason: null,\n\n currentWriteId: null,\n\n currentInputSnapshot: null,\n\n currentOutputSnapshotRaw: null,\n\n currentOutputSnapshotResolved: null\n };\n\n // Run transaction initially.\n const currentState = this.getLatestState_(path);\n transaction.currentInputSnapshot = currentState;\n const newVal = transaction.update(currentState.val());\n if (newVal === undefined) {\n // Abort transaction.\n transaction.unwatcher();\n transaction.currentOutputSnapshotRaw = null;\n transaction.currentOutputSnapshotResolved = null;\n if (transaction.onComplete) {\n // We just set the input snapshot, so this cast should be safe\n const snapshot = new DataSnapshot(\n transaction.currentInputSnapshot,\n new Reference(this, transaction.path),\n PRIORITY_INDEX\n );\n transaction.onComplete(null, false, snapshot);\n }\n } else {\n validateFirebaseData(\n 'transaction failed: Data returned ',\n newVal,\n transaction.path\n );\n\n // Mark as run and add to our queue.\n transaction.status = TransactionStatus.RUN;\n const queueNode = this.transactionQueueTree_.subTree(path);\n const nodeQueue = queueNode.getValue() || [];\n nodeQueue.push(transaction);\n\n queueNode.setValue(nodeQueue);\n\n // Update visibleData and raise events\n // Note: We intentionally raise events after updating all of our transaction state, since the user could\n // start new transactions from the event callbacks.\n let priorityForNode;\n if (\n typeof newVal === 'object' &&\n newVal !== null &&\n contains(newVal, '.priority')\n ) {\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n priorityForNode = safeGet(newVal as any, '.priority');\n assert(\n isValidPriority(priorityForNode),\n 'Invalid priority returned by transaction. ' +\n 'Priority must be a valid string, finite number, server value, or null.'\n );\n } else {\n const currentNode =\n this.serverSyncTree_.calcCompleteEventCache(path) ||\n ChildrenNode.EMPTY_NODE;\n priorityForNode = currentNode.getPriority().val();\n }\n priorityForNode /** @type {null|number|string} */ = priorityForNode;\n\n const serverValues = this.generateServerValues();\n const newNodeUnresolved = nodeFromJSON(newVal, priorityForNode);\n const newNode = resolveDeferredValueSnapshot(\n newNodeUnresolved,\n currentState,\n serverValues\n );\n transaction.currentOutputSnapshotRaw = newNodeUnresolved;\n transaction.currentOutputSnapshotResolved = newNode;\n transaction.currentWriteId = this.getNextWriteId_();\n\n const events = this.serverSyncTree_.applyUserOverwrite(\n path,\n newNode,\n transaction.currentWriteId,\n transaction.applyLocally\n );\n this.eventQueue_.raiseEventsForChangedPath(path, events);\n\n this.sendReadyTransactions_();\n }\n};\n\n/**\n * @param {!Path} path\n * @param {Array.=} excludeSets A specific set to exclude\n * @return {Node}\n * @private\n */\n// eslint-disable-next-line @typescript-eslint/no-explicit-any\n(Repo.prototype as any).getLatestState_ = function(\n path: Path,\n excludeSets?: number[]\n): Node {\n return (\n this.serverSyncTree_.calcCompleteEventCache(path, excludeSets) ||\n ChildrenNode.EMPTY_NODE\n );\n};\n\n/**\n * Sends any already-run transactions that aren't waiting for outstanding transactions to\n * complete.\n *\n * Externally it's called with no arguments, but it calls itself recursively with a particular\n * transactionQueueTree node to recurse through the tree.\n *\n * @param {Tree.>=} node transactionQueueTree node to start at.\n * @private\n */\n// eslint-disable-next-line @typescript-eslint/no-explicit-any\n(Repo.prototype as any).sendReadyTransactions_ = function(\n node: Tree = this.transactionQueueTree_\n) {\n // Before recursing, make sure any completed transactions are removed.\n if (!node) {\n this.pruneCompletedTransactionsBelowNode_(node);\n }\n\n if (node.getValue() !== null) {\n const queue = this.buildTransactionQueue_(node);\n assert(queue.length > 0, 'Sending zero length transaction queue');\n\n const allRun = queue.every(\n (transaction: Transaction) => transaction.status === TransactionStatus.RUN\n );\n\n // If they're all run (and not sent), we can send them. Else, we must wait.\n if (allRun) {\n this.sendTransactionQueue_(node.path(), queue);\n }\n } else if (node.hasChildren()) {\n node.forEachChild(childNode => {\n this.sendReadyTransactions_(childNode);\n });\n }\n};\n\n/**\n * Given a list of run transactions, send them to the server and then handle the result (success or failure).\n *\n * @param {!Path} path The location of the queue.\n * @param {!Array.} queue Queue of transactions under the specified location.\n * @private\n */\n// eslint-disable-next-line @typescript-eslint/no-explicit-any\n(Repo.prototype as any).sendTransactionQueue_ = function(\n path: Path,\n queue: Transaction[]\n) {\n // Mark transactions as sent and increment retry count!\n const setsToIgnore = queue.map(txn => {\n return txn.currentWriteId;\n });\n const latestState = this.getLatestState_(path, setsToIgnore);\n let snapToSend = latestState;\n const latestHash = latestState.hash();\n for (let i = 0; i < queue.length; i++) {\n const txn = queue[i];\n assert(\n txn.status === TransactionStatus.RUN,\n 'tryToSendTransactionQueue_: items in queue should all be run.'\n );\n txn.status = TransactionStatus.SENT;\n txn.retryCount++;\n const relativePath = Path.relativePath(path, txn.path);\n // If we've gotten to this point, the output snapshot must be defined.\n snapToSend = snapToSend.updateChild(\n relativePath /** @type {!Node} */,\n txn.currentOutputSnapshotRaw\n );\n }\n\n const dataToSend = snapToSend.val(true);\n const pathToSend = path;\n\n // Send the put.\n this.server_.put(\n pathToSend.toString(),\n dataToSend,\n (status: string) => {\n this.log_('transaction put response', {\n path: pathToSend.toString(),\n status\n });\n\n let events: Event[] = [];\n if (status === 'ok') {\n // Queue up the callbacks and fire them after cleaning up all of our transaction state, since\n // the callback could trigger more transactions or sets.\n const callbacks = [];\n for (let i = 0; i < queue.length; i++) {\n queue[i].status = TransactionStatus.COMPLETED;\n events = events.concat(\n this.serverSyncTree_.ackUserWrite(queue[i].currentWriteId)\n );\n if (queue[i].onComplete) {\n // We never unset the output snapshot, and given that this transaction is complete, it should be set\n const node = queue[i].currentOutputSnapshotResolved as Node;\n const ref = new Reference(this, queue[i].path);\n const snapshot = new DataSnapshot(node, ref, PRIORITY_INDEX);\n callbacks.push(\n queue[i].onComplete.bind(null, null, true, snapshot)\n );\n }\n queue[i].unwatcher();\n }\n\n // Now remove the completed transactions.\n this.pruneCompletedTransactionsBelowNode_(\n this.transactionQueueTree_.subTree(path)\n );\n // There may be pending transactions that we can now send.\n this.sendReadyTransactions_();\n\n this.eventQueue_.raiseEventsForChangedPath(path, events);\n\n // Finally, trigger onComplete callbacks.\n for (let i = 0; i < callbacks.length; i++) {\n exceptionGuard(callbacks[i]);\n }\n } else {\n // transactions are no longer sent. Update their status appropriately.\n if (status === 'datastale') {\n for (let i = 0; i < queue.length; i++) {\n if (queue[i].status === TransactionStatus.SENT_NEEDS_ABORT) {\n queue[i].status = TransactionStatus.NEEDS_ABORT;\n } else {\n queue[i].status = TransactionStatus.RUN;\n }\n }\n } else {\n warn(\n 'transaction at ' + pathToSend.toString() + ' failed: ' + status\n );\n for (let i = 0; i < queue.length; i++) {\n queue[i].status = TransactionStatus.NEEDS_ABORT;\n queue[i].abortReason = status;\n }\n }\n\n this.rerunTransactions_(path);\n }\n },\n latestHash\n );\n};\n\n/**\n * Finds all transactions dependent on the data at changedPath and reruns them.\n *\n * Should be called any time cached data changes.\n *\n * Return the highest path that was affected by rerunning transactions. This is the path at which events need to\n * be raised for.\n *\n * @param {!Path} changedPath The path in mergedData that changed.\n * @return {!Path} The rootmost path that was affected by rerunning transactions.\n * @private\n */\n// eslint-disable-next-line @typescript-eslint/no-explicit-any\n(Repo.prototype as any).rerunTransactions_ = function(changedPath: Path): Path {\n const rootMostTransactionNode = this.getAncestorTransactionNode_(changedPath);\n const path = rootMostTransactionNode.path();\n\n const queue = this.buildTransactionQueue_(rootMostTransactionNode);\n this.rerunTransactionQueue_(queue, path);\n\n return path;\n};\n\n/**\n * Does all the work of rerunning transactions (as well as cleans up aborted transactions and whatnot).\n *\n * @param {Array.} queue The queue of transactions to run.\n * @param {!Path} path The path the queue is for.\n * @private\n */\n// eslint-disable-next-line @typescript-eslint/no-explicit-any\n(Repo.prototype as any).rerunTransactionQueue_ = function(\n queue: Transaction[],\n path: Path\n) {\n if (queue.length === 0) {\n return; // Nothing to do!\n }\n\n // Queue up the callbacks and fire them after cleaning up all of our transaction state, since\n // the callback could trigger more transactions or sets.\n const callbacks = [];\n let events: Event[] = [];\n // Ignore all of the sets we're going to re-run.\n const txnsToRerun = queue.filter(q => {\n return q.status === TransactionStatus.RUN;\n });\n const setsToIgnore = txnsToRerun.map(q => {\n return q.currentWriteId;\n });\n for (let i = 0; i < queue.length; i++) {\n const transaction = queue[i];\n const relativePath = Path.relativePath(path, transaction.path);\n let abortTransaction = false,\n abortReason;\n assert(\n relativePath !== null,\n 'rerunTransactionsUnderNode_: relativePath should not be null.'\n );\n\n if (transaction.status === TransactionStatus.NEEDS_ABORT) {\n abortTransaction = true;\n abortReason = transaction.abortReason;\n events = events.concat(\n this.serverSyncTree_.ackUserWrite(transaction.currentWriteId, true)\n );\n } else if (transaction.status === TransactionStatus.RUN) {\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n if (transaction.retryCount >= (Repo as any).MAX_TRANSACTION_RETRIES_) {\n abortTransaction = true;\n abortReason = 'maxretry';\n events = events.concat(\n this.serverSyncTree_.ackUserWrite(transaction.currentWriteId, true)\n );\n } else {\n // This code reruns a transaction\n const currentNode = this.getLatestState_(\n transaction.path,\n setsToIgnore\n );\n transaction.currentInputSnapshot = currentNode;\n const newData = queue[i].update(currentNode.val());\n if (newData !== undefined) {\n validateFirebaseData(\n 'transaction failed: Data returned ',\n newData,\n transaction.path\n );\n let newDataNode = nodeFromJSON(newData);\n const hasExplicitPriority =\n typeof newData === 'object' &&\n newData != null &&\n contains(newData, '.priority');\n if (!hasExplicitPriority) {\n // Keep the old priority if there wasn't a priority explicitly specified.\n newDataNode = newDataNode.updatePriority(currentNode.getPriority());\n }\n\n const oldWriteId = transaction.currentWriteId;\n const serverValues = this.generateServerValues();\n const newNodeResolved = resolveDeferredValueSnapshot(\n newDataNode,\n currentNode,\n serverValues\n );\n\n transaction.currentOutputSnapshotRaw = newDataNode;\n transaction.currentOutputSnapshotResolved = newNodeResolved;\n transaction.currentWriteId = this.getNextWriteId_();\n // Mutates setsToIgnore in place\n setsToIgnore.splice(setsToIgnore.indexOf(oldWriteId), 1);\n events = events.concat(\n this.serverSyncTree_.applyUserOverwrite(\n transaction.path,\n newNodeResolved,\n transaction.currentWriteId,\n transaction.applyLocally\n )\n );\n events = events.concat(\n this.serverSyncTree_.ackUserWrite(oldWriteId, true)\n );\n } else {\n abortTransaction = true;\n abortReason = 'nodata';\n events = events.concat(\n this.serverSyncTree_.ackUserWrite(transaction.currentWriteId, true)\n );\n }\n }\n }\n this.eventQueue_.raiseEventsForChangedPath(path, events);\n events = [];\n if (abortTransaction) {\n // Abort.\n queue[i].status = TransactionStatus.COMPLETED;\n\n // Removing a listener can trigger pruning which can muck with mergedData/visibleData (as it prunes data).\n // So defer the unwatcher until we're done.\n (function(unwatcher) {\n setTimeout(unwatcher, Math.floor(0));\n })(queue[i].unwatcher);\n\n if (queue[i].onComplete) {\n if (abortReason === 'nodata') {\n const ref = new Reference(this, queue[i].path);\n // We set this field immediately, so it's safe to cast to an actual snapshot\n const lastInput /** @type {!Node} */ = queue[i].currentInputSnapshot;\n const snapshot = new DataSnapshot(lastInput, ref, PRIORITY_INDEX);\n callbacks.push(queue[i].onComplete.bind(null, null, false, snapshot));\n } else {\n callbacks.push(\n queue[i].onComplete.bind(null, new Error(abortReason), false, null)\n );\n }\n }\n }\n }\n\n // Clean up completed transactions.\n this.pruneCompletedTransactionsBelowNode_(this.transactionQueueTree_);\n\n // Now fire callbacks, now that we're in a good, known state.\n for (let i = 0; i < callbacks.length; i++) {\n exceptionGuard(callbacks[i]);\n }\n\n // Try to send the transaction result to the server.\n this.sendReadyTransactions_();\n};\n\n/**\n * Returns the rootmost ancestor node of the specified path that has a pending transaction on it, or just returns\n * the node for the given path if there are no pending transactions on any ancestor.\n *\n * @param {!Path} path The location to start at.\n * @return {!Tree.>} The rootmost node with a transaction.\n * @private\n */\n// eslint-disable-next-line @typescript-eslint/no-explicit-any\n(Repo.prototype as any).getAncestorTransactionNode_ = function(\n path: Path\n): Tree {\n let front;\n\n // Start at the root and walk deeper into the tree towards path until we find a node with pending transactions.\n let transactionNode = this.transactionQueueTree_;\n front = path.getFront();\n while (front !== null && transactionNode.getValue() === null) {\n transactionNode = transactionNode.subTree(front);\n path = path.popFront();\n front = path.getFront();\n }\n\n return transactionNode;\n};\n\n/**\n * Builds the queue of all transactions at or below the specified transactionNode.\n *\n * @param {!Tree.>} transactionNode\n * @return {Array.} The generated queue.\n * @private\n */\n// eslint-disable-next-line @typescript-eslint/no-explicit-any\n(Repo.prototype as any).buildTransactionQueue_ = function(\n transactionNode: Tree\n): Transaction[] {\n // Walk any child transaction queues and aggregate them into a single queue.\n const transactionQueue: Transaction[] = [];\n this.aggregateTransactionQueuesForNode_(transactionNode, transactionQueue);\n\n // Sort them by the order the transactions were created.\n transactionQueue.sort((a, b) => {\n return a.order - b.order;\n });\n\n return transactionQueue;\n};\n\n/**\n * @param {!Tree.>} node\n * @param {Array.} queue\n * @private\n */\n// eslint-disable-next-line @typescript-eslint/no-explicit-any\n(Repo.prototype as any).aggregateTransactionQueuesForNode_ = function(\n node: Tree,\n queue: Transaction[]\n) {\n const nodeQueue = node.getValue();\n if (nodeQueue !== null) {\n for (let i = 0; i < nodeQueue.length; i++) {\n queue.push(nodeQueue[i]);\n }\n }\n\n node.forEachChild(child => {\n this.aggregateTransactionQueuesForNode_(child, queue);\n });\n};\n\n/**\n * Remove COMPLETED transactions at or below this node in the transactionQueueTree_.\n *\n * @param {!Tree.>} node\n * @private\n */\n// eslint-disable-next-line @typescript-eslint/no-explicit-any\n(Repo.prototype as any).pruneCompletedTransactionsBelowNode_ = function(\n node: Tree\n) {\n const queue = node.getValue();\n if (queue) {\n let to = 0;\n for (let from = 0; from < queue.length; from++) {\n if (queue[from].status !== TransactionStatus.COMPLETED) {\n queue[to] = queue[from];\n to++;\n }\n }\n queue.length = to;\n node.setValue(queue.length > 0 ? queue : null);\n }\n\n node.forEachChild(childNode => {\n this.pruneCompletedTransactionsBelowNode_(childNode);\n });\n};\n\n/**\n * Aborts all transactions on ancestors or descendants of the specified path. Called when doing a set() or update()\n * since we consider them incompatible with transactions.\n *\n * @param {!Path} path Path for which we want to abort related transactions.\n * @return {!Path}\n * @private\n */\n// eslint-disable-next-line @typescript-eslint/no-explicit-any\n(Repo.prototype as any).abortTransactions_ = function(path: Path): Path {\n const affectedPath = this.getAncestorTransactionNode_(path).path();\n\n const transactionNode = this.transactionQueueTree_.subTree(path);\n\n transactionNode.forEachAncestor((node: Tree) => {\n this.abortTransactionsOnNode_(node);\n });\n\n this.abortTransactionsOnNode_(transactionNode);\n\n transactionNode.forEachDescendant((node: Tree) => {\n this.abortTransactionsOnNode_(node);\n });\n\n return affectedPath;\n};\n\n/**\n * Abort transactions stored in this transaction queue node.\n *\n * @param {!Tree.>} node Node to abort transactions for.\n * @private\n */\n// eslint-disable-next-line @typescript-eslint/no-explicit-any\n(Repo.prototype as any).abortTransactionsOnNode_ = function(\n node: Tree\n) {\n const queue = node.getValue();\n if (queue !== null) {\n // Queue up the callbacks and fire them after cleaning up all of our transaction state, since\n // the callback could trigger more transactions or sets.\n const callbacks = [];\n\n // Go through queue. Any already-sent transactions must be marked for abort, while the unsent ones\n // can be immediately aborted and removed.\n let events: Event[] = [];\n let lastSent = -1;\n for (let i = 0; i < queue.length; i++) {\n if (queue[i].status === TransactionStatus.SENT_NEEDS_ABORT) {\n // Already marked. No action needed.\n } else if (queue[i].status === TransactionStatus.SENT) {\n assert(\n lastSent === i - 1,\n 'All SENT items should be at beginning of queue.'\n );\n lastSent = i;\n // Mark transaction for abort when it comes back.\n queue[i].status = TransactionStatus.SENT_NEEDS_ABORT;\n queue[i].abortReason = 'set';\n } else {\n assert(\n queue[i].status === TransactionStatus.RUN,\n 'Unexpected transaction status in abort'\n );\n // We can abort it immediately.\n queue[i].unwatcher();\n events = events.concat(\n this.serverSyncTree_.ackUserWrite(queue[i].currentWriteId, true)\n );\n if (queue[i].onComplete) {\n const snapshot: DataSnapshot | null = null;\n callbacks.push(\n queue[i].onComplete.bind(null, new Error('set'), false, snapshot)\n );\n }\n }\n }\n if (lastSent === -1) {\n // We're not waiting for any sent transactions. We can clear the queue.\n node.setValue(null);\n } else {\n // Remove the transactions we aborted.\n queue.length = lastSent + 1;\n }\n\n // Now fire the callbacks.\n this.eventQueue_.raiseEventsForChangedPath(node.path(), events);\n for (let i = 0; i < callbacks.length; i++) {\n exceptionGuard(callbacks[i]);\n }\n }\n};\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { FirebaseApp } from '@firebase/app-types';\nimport { safeGet } from '@firebase/util';\nimport { Repo } from './Repo';\nimport { fatal } from './util/util';\nimport { parseRepoInfo } from './util/libs/parser';\nimport { validateUrl } from './util/validation';\nimport './Repo_transaction';\nimport { Database } from '../api/Database';\nimport { RepoInfo } from './RepoInfo';\nimport { FirebaseAuthInternalName } from '@firebase/auth-interop-types';\nimport { Provider } from '@firebase/component';\n\n/** @const {string} */\nconst DATABASE_URL_OPTION = 'databaseURL';\n\n/**\n * This variable is also defined in the firebase node.js admin SDK. Before\n * modifying this definition, consult the definition in:\n *\n * https://github.com/firebase/firebase-admin-node\n *\n * and make sure the two are consistent.\n */\nconst FIREBASE_DATABASE_EMULATOR_HOST_VAR = 'FIREBASE_DATABASE_EMULATOR_HOST';\n\nlet _staticInstance: RepoManager;\n\n/**\n * Creates and caches Repo instances.\n */\nexport class RepoManager {\n /**\n * @private {!Object.>}\n */\n private repos_: {\n [appName: string]: {\n [dbUrl: string]: Repo;\n };\n } = {};\n\n /**\n * If true, new Repos will be created to use ReadonlyRestClient (for testing purposes).\n * @private {boolean}\n */\n private useRestClient_: boolean = false;\n\n static getInstance(): RepoManager {\n if (!_staticInstance) {\n _staticInstance = new RepoManager();\n }\n return _staticInstance;\n }\n\n // TODO(koss): Remove these functions unless used in tests?\n interrupt() {\n for (const appName of Object.keys(this.repos_)) {\n for (const dbUrl of Object.keys(this.repos_[appName])) {\n this.repos_[appName][dbUrl].interrupt();\n }\n }\n }\n\n resume() {\n for (const appName of Object.keys(this.repos_)) {\n for (const dbUrl of Object.keys(this.repos_[appName])) {\n this.repos_[appName][dbUrl].resume();\n }\n }\n }\n\n /**\n * This function should only ever be called to CREATE a new database instance.\n *\n * @param {!FirebaseApp} app\n * @return {!Database}\n */\n databaseFromApp(\n app: FirebaseApp,\n authProvider: Provider,\n url?: string\n ): Database {\n let dbUrl: string | undefined = url || app.options[DATABASE_URL_OPTION];\n if (dbUrl === undefined) {\n fatal(\n \"Can't determine Firebase Database URL. Be sure to include \" +\n DATABASE_URL_OPTION +\n ' option when calling firebase.initializeApp().'\n );\n }\n\n let parsedUrl = parseRepoInfo(dbUrl);\n let repoInfo = parsedUrl.repoInfo;\n\n let dbEmulatorHost: string | undefined = undefined;\n if (typeof process !== 'undefined') {\n dbEmulatorHost = process.env[FIREBASE_DATABASE_EMULATOR_HOST_VAR];\n }\n if (dbEmulatorHost) {\n dbUrl = `http://${dbEmulatorHost}?ns=${repoInfo.namespace}`;\n parsedUrl = parseRepoInfo(dbUrl);\n repoInfo = parsedUrl.repoInfo;\n }\n\n validateUrl('Invalid Firebase Database URL', 1, parsedUrl);\n if (!parsedUrl.path.isEmpty()) {\n fatal(\n 'Database URL must point to the root of a Firebase Database ' +\n '(not including a child path).'\n );\n }\n\n const repo = this.createRepo(repoInfo, app, authProvider);\n\n return repo.database;\n }\n\n /**\n * Remove the repo and make sure it is disconnected.\n *\n * @param {!Repo} repo\n */\n deleteRepo(repo: Repo) {\n const appRepos = safeGet(this.repos_, repo.app.name);\n // This should never happen...\n if (!appRepos || safeGet(appRepos, repo.repoInfo_.toURLString()) !== repo) {\n fatal(\n `Database ${repo.app.name}(${repo.repoInfo_}) has already been deleted.`\n );\n }\n repo.interrupt();\n delete appRepos[repo.repoInfo_.toURLString()];\n }\n\n /**\n * Ensures a repo doesn't already exist and then creates one using the\n * provided app.\n *\n * @param {!RepoInfo} repoInfo The metadata about the Repo\n * @param {!FirebaseApp} app\n * @return {!Repo} The Repo object for the specified server / repoName.\n */\n createRepo(\n repoInfo: RepoInfo,\n app: FirebaseApp,\n authProvider: Provider\n ): Repo {\n let appRepos = safeGet(this.repos_, app.name);\n\n if (!appRepos) {\n appRepos = {};\n this.repos_[app.name] = appRepos;\n }\n\n let repo = safeGet(appRepos, repoInfo.toURLString());\n if (repo) {\n fatal(\n 'Database initialized multiple times. Please make sure the format of the database URL matches with each database() call.'\n );\n }\n repo = new Repo(repoInfo, this.useRestClient_, app, authProvider);\n appRepos[repoInfo.toURLString()] = repo;\n\n return repo;\n }\n\n /**\n * Forces us to use ReadonlyRestClient instead of PersistentConnection for new Repos.\n * @param {boolean} forceRestClient\n */\n forceRestClient(forceRestClient: boolean) {\n this.useRestClient_ = forceRestClient;\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { fatal } from '../core/util/util';\nimport { parseRepoInfo } from '../core/util/libs/parser';\nimport { Path } from '../core/util/Path';\nimport { Reference } from './Reference';\nimport { Repo } from '../core/Repo';\nimport { RepoManager } from '../core/RepoManager';\nimport { validateArgCount } from '@firebase/util';\nimport { validateUrl } from '../core/util/validation';\nimport { FirebaseApp } from '@firebase/app-types';\nimport { FirebaseService } from '@firebase/app-types/private';\nimport { RepoInfo } from '../core/RepoInfo';\nimport { FirebaseDatabase } from '@firebase/database-types';\n\n/**\n * Class representing a firebase database.\n * @implements {FirebaseService}\n */\nexport class Database implements FirebaseService {\n INTERNAL: DatabaseInternals;\n private root_: Reference;\n\n static readonly ServerValue = {\n TIMESTAMP: {\n '.sv': 'timestamp'\n },\n increment: (delta: number) => {\n return {\n '.sv': {\n 'increment': delta\n }\n };\n }\n };\n\n /**\n * The constructor should not be called by users of our public API.\n * @param {!Repo} repo_\n */\n constructor(private repo_: Repo) {\n if (!(repo_ instanceof Repo)) {\n fatal(\n \"Don't call new Database() directly - please use firebase.database().\"\n );\n }\n\n /** @type {Reference} */\n this.root_ = new Reference(repo_, Path.Empty);\n\n this.INTERNAL = new DatabaseInternals(this);\n }\n\n get app(): FirebaseApp {\n return this.repo_.app;\n }\n\n /**\n * Returns a reference to the root or to the path specified in the provided\n * argument.\n *\n * @param {string|Reference=} path The relative string path or an existing\n * Reference to a database location.\n * @throws If a Reference is provided, throws if it does not belong to the\n * same project.\n * @return {!Reference} Firebase reference.\n */\n ref(path?: string): Reference;\n ref(path?: Reference): Reference;\n ref(path?: string | Reference): Reference {\n this.checkDeleted_('ref');\n validateArgCount('database.ref', 0, 1, arguments.length);\n\n if (path instanceof Reference) {\n return this.refFromURL(path.toString());\n }\n\n return path !== undefined ? this.root_.child(path) : this.root_;\n }\n\n /**\n * Returns a reference to the root or the path specified in url.\n * We throw a exception if the url is not in the same domain as the\n * current repo.\n * @param {string} url\n * @return {!Reference} Firebase reference.\n */\n refFromURL(url: string): Reference {\n /** @const {string} */\n const apiName = 'database.refFromURL';\n this.checkDeleted_(apiName);\n validateArgCount(apiName, 1, 1, arguments.length);\n const parsedURL = parseRepoInfo(url);\n validateUrl(apiName, 1, parsedURL);\n\n const repoInfo = parsedURL.repoInfo;\n if (repoInfo.host !== (this.repo_.repoInfo_ as RepoInfo).host) {\n fatal(\n apiName +\n ': Host name does not match the current database: ' +\n '(found ' +\n repoInfo.host +\n ' but expected ' +\n (this.repo_.repoInfo_ as RepoInfo).host +\n ')'\n );\n }\n\n return this.ref(parsedURL.path.toString());\n }\n\n /**\n * @param {string} apiName\n */\n private checkDeleted_(apiName: string) {\n if (this.repo_ === null) {\n fatal('Cannot call ' + apiName + ' on a deleted database.');\n }\n }\n\n // Make individual repo go offline.\n goOffline() {\n validateArgCount('database.goOffline', 0, 0, arguments.length);\n this.checkDeleted_('goOffline');\n this.repo_.interrupt();\n }\n\n goOnline() {\n validateArgCount('database.goOnline', 0, 0, arguments.length);\n this.checkDeleted_('goOnline');\n this.repo_.resume();\n }\n}\n\nexport class DatabaseInternals {\n /** @param {!Database} database */\n constructor(public database: Database) {}\n\n /** @return {Promise} */\n async delete(): Promise {\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n (this.database as any).checkDeleted_('delete');\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n RepoManager.getInstance().deleteRepo((this.database as any).repo_ as Repo);\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n (this.database as any).repo_ = null;\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n (this.database as any).root_ = null;\n this.database.INTERNAL = null;\n this.database = null;\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { WebSocketConnection } from '../realtime/WebSocketConnection';\nimport { BrowserPollConnection } from '../realtime/BrowserPollConnection';\nimport { Reference } from './Reference';\n\n/**\n * INTERNAL methods for internal-use only (tests, etc.).\n *\n * Customers shouldn't use these or else should be aware that they could break at any time.\n *\n * @const\n */\n\nexport const forceLongPolling = function() {\n WebSocketConnection.forceDisallow();\n BrowserPollConnection.forceAllow();\n};\n\nexport const forceWebSockets = function() {\n BrowserPollConnection.forceDisallow();\n};\n\n/* Used by App Manager */\nexport const isWebSocketsAvailable = function(): boolean {\n return WebSocketConnection['isAvailable']();\n};\n\nexport const setSecurityDebugCallback = function(\n ref: Reference,\n callback: (a: object) => void\n) {\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n (ref.repo.persistentConnection_ as any).securityDebugCallback_ = callback;\n};\n\nexport const stats = function(ref: Reference, showDelta?: boolean) {\n ref.repo.stats(showDelta);\n};\n\nexport const statsIncrementCounter = function(ref: Reference, metric: string) {\n ref.repo.statsIncrementCounter(metric);\n};\n\nexport const dataUpdateCount = function(ref: Reference): number {\n return ref.repo.dataUpdateCount;\n};\n\nexport const interceptServerData = function(\n ref: Reference,\n callback: ((a: string, b: unknown) => void) | null\n) {\n return ref.repo.interceptServerData_(callback);\n};\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { RepoInfo } from '../core/RepoInfo';\nimport { PersistentConnection } from '../core/PersistentConnection';\nimport { RepoManager } from '../core/RepoManager';\nimport { Connection } from '../realtime/Connection';\nimport { Query } from './Query';\n\nexport const DataConnection = PersistentConnection;\n\n/**\n * @param {!string} pathString\n * @param {function(*)} onComplete\n */\n// eslint-disable-next-line @typescript-eslint/no-explicit-any\n(PersistentConnection.prototype as any).simpleListen = function(\n pathString: string,\n onComplete: (a: unknown) => void\n) {\n this.sendRequest('q', { p: pathString }, onComplete);\n};\n\n/**\n * @param {*} data\n * @param {function(*)} onEcho\n */\n// eslint-disable-next-line @typescript-eslint/no-explicit-any\n(PersistentConnection.prototype as any).echo = function(\n data: unknown,\n onEcho: (a: unknown) => void\n) {\n this.sendRequest('echo', { d: data }, onEcho);\n};\n\n// RealTimeConnection properties that we use in tests.\nexport const RealTimeConnection = Connection;\n\n/**\n * @param {function(): string} newHash\n * @return {function()}\n */\nexport const hijackHash = function(newHash: () => string) {\n const oldPut = PersistentConnection.prototype.put;\n PersistentConnection.prototype.put = function(\n pathString,\n data,\n onComplete,\n hash\n ) {\n if (hash !== undefined) {\n hash = newHash();\n }\n oldPut.call(this, pathString, data, onComplete, hash);\n };\n return function() {\n PersistentConnection.prototype.put = oldPut;\n };\n};\n\n/**\n * @type {function(new:RepoInfo, !string, boolean, !string, boolean): undefined}\n */\nexport const ConnectionTarget = RepoInfo;\n\n/**\n * @param {!Query} query\n * @return {!string}\n */\nexport const queryIdentifier = function(query: Query) {\n return query.queryIdentifier();\n};\n\n/**\n * Forces the RepoManager to create Repos that use ReadonlyRestClient instead of PersistentConnection.\n *\n * @param {boolean} forceRestClient\n */\nexport const forceRestClient = function(forceRestClient: boolean) {\n RepoManager.getInstance().forceRestClient(forceRestClient);\n};\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\n/**\n * Simple wrapper around a nullable UID. Mostly exists to make code more\n * readable.\n */\nexport class User {\n /** A user with a null UID. */\n static readonly UNAUTHENTICATED = new User(null);\n\n // TODO(mikelehen): Look into getting a proper uid-equivalent for\n // non-FirebaseAuth providers.\n static readonly GOOGLE_CREDENTIALS = new User('google-credentials-uid');\n static readonly FIRST_PARTY = new User('first-party-uid');\n\n constructor(readonly uid: string | null) {}\n\n isAuthenticated(): boolean {\n return this.uid != null;\n }\n\n /**\n * Returns a key representing this user, suitable for inclusion in a\n * dictionary.\n */\n toKey(): string {\n if (this.isAuthenticated()) {\n return 'uid:' + this.uid;\n } else {\n return 'anonymous-user';\n }\n }\n\n isEqual(otherUser: User): boolean {\n return otherUser.uid === this.uid;\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport * as firestore from '@firebase/firestore-types';\n\n/**\n * Error Codes describing the different ways Firestore can fail. These come\n * directly from GRPC.\n */\nexport type Code = firestore.FirestoreErrorCode;\n\nexport const Code = {\n // Causes are copied from:\n // https://github.com/grpc/grpc/blob/bceec94ea4fc5f0085d81235d8e1c06798dc341a/include/grpc%2B%2B/impl/codegen/status_code_enum.h\n /** Not an error; returned on success. */\n OK: 'ok' as Code,\n\n /** The operation was cancelled (typically by the caller). */\n CANCELLED: 'cancelled' as Code,\n\n /** Unknown error or an error from a different error domain. */\n UNKNOWN: 'unknown' as Code,\n\n /**\n * Client specified an invalid argument. Note that this differs from\n * FAILED_PRECONDITION. INVALID_ARGUMENT indicates arguments that are\n * problematic regardless of the state of the system (e.g., a malformed file\n * name).\n */\n INVALID_ARGUMENT: 'invalid-argument' as Code,\n\n /**\n * Deadline expired before operation could complete. For operations that\n * change the state of the system, this error may be returned even if the\n * operation has completed successfully. For example, a successful response\n * from a server could have been delayed long enough for the deadline to\n * expire.\n */\n DEADLINE_EXCEEDED: 'deadline-exceeded' as Code,\n\n /** Some requested entity (e.g., file or directory) was not found. */\n NOT_FOUND: 'not-found' as Code,\n\n /**\n * Some entity that we attempted to create (e.g., file or directory) already\n * exists.\n */\n ALREADY_EXISTS: 'already-exists' as Code,\n\n /**\n * The caller does not have permission to execute the specified operation.\n * PERMISSION_DENIED must not be used for rejections caused by exhausting\n * some resource (use RESOURCE_EXHAUSTED instead for those errors).\n * PERMISSION_DENIED must not be used if the caller can not be identified\n * (use UNAUTHENTICATED instead for those errors).\n */\n PERMISSION_DENIED: 'permission-denied' as Code,\n\n /**\n * The request does not have valid authentication credentials for the\n * operation.\n */\n UNAUTHENTICATED: 'unauthenticated' as Code,\n\n /**\n * Some resource has been exhausted, perhaps a per-user quota, or perhaps the\n * entire file system is out of space.\n */\n RESOURCE_EXHAUSTED: 'resource-exhausted' as Code,\n\n /**\n * Operation was rejected because the system is not in a state required for\n * the operation's execution. For example, directory to be deleted may be\n * non-empty, an rmdir operation is applied to a non-directory, etc.\n *\n * A litmus test that may help a service implementor in deciding\n * between FAILED_PRECONDITION, ABORTED, and UNAVAILABLE:\n * (a) Use UNAVAILABLE if the client can retry just the failing call.\n * (b) Use ABORTED if the client should retry at a higher-level\n * (e.g., restarting a read-modify-write sequence).\n * (c) Use FAILED_PRECONDITION if the client should not retry until\n * the system state has been explicitly fixed. E.g., if an \"rmdir\"\n * fails because the directory is non-empty, FAILED_PRECONDITION\n * should be returned since the client should not retry unless\n * they have first fixed up the directory by deleting files from it.\n * (d) Use FAILED_PRECONDITION if the client performs conditional\n * REST Get/Update/Delete on a resource and the resource on the\n * server does not match the condition. E.g., conflicting\n * read-modify-write on the same resource.\n */\n FAILED_PRECONDITION: 'failed-precondition' as Code,\n\n /**\n * The operation was aborted, typically due to a concurrency issue like\n * sequencer check failures, transaction aborts, etc.\n *\n * See litmus test above for deciding between FAILED_PRECONDITION, ABORTED,\n * and UNAVAILABLE.\n */\n ABORTED: 'aborted' as Code,\n\n /**\n * Operation was attempted past the valid range. E.g., seeking or reading\n * past end of file.\n *\n * Unlike INVALID_ARGUMENT, this error indicates a problem that may be fixed\n * if the system state changes. For example, a 32-bit file system will\n * generate INVALID_ARGUMENT if asked to read at an offset that is not in the\n * range [0,2^32-1], but it will generate OUT_OF_RANGE if asked to read from\n * an offset past the current file size.\n *\n * There is a fair bit of overlap between FAILED_PRECONDITION and\n * OUT_OF_RANGE. We recommend using OUT_OF_RANGE (the more specific error)\n * when it applies so that callers who are iterating through a space can\n * easily look for an OUT_OF_RANGE error to detect when they are done.\n */\n OUT_OF_RANGE: 'out-of-range' as Code,\n\n /** Operation is not implemented or not supported/enabled in this service. */\n UNIMPLEMENTED: 'unimplemented' as Code,\n\n /**\n * Internal errors. Means some invariants expected by underlying System has\n * been broken. If you see one of these errors, Something is very broken.\n */\n INTERNAL: 'internal' as Code,\n\n /**\n * The service is currently unavailable. This is a most likely a transient\n * condition and may be corrected by retrying with a backoff.\n *\n * See litmus test above for deciding between FAILED_PRECONDITION, ABORTED,\n * and UNAVAILABLE.\n */\n UNAVAILABLE: 'unavailable' as Code,\n\n /** Unrecoverable data loss or corruption. */\n DATA_LOSS: 'data-loss' as Code\n};\n\n/**\n * An error class used for Firestore-generated errors. Ideally we should be\n * using FirebaseError, but integrating with it is overly arduous at the moment,\n * so we define our own compatible error class (with a `name` of 'FirebaseError'\n * and compatible `code` and `message` fields.)\n */\nexport class FirestoreError extends Error implements firestore.FirestoreError {\n name = 'FirebaseError';\n stack?: string;\n\n constructor(readonly code: Code, readonly message: string) {\n super(message);\n\n // HACK: We write a toString property directly because Error is not a real\n // class and so inheritance does not work correctly. We could alternatively\n // do the same \"back-door inheritance\" trick that FirebaseError does.\n this.toString = () => `${this.name}: [code=${this.code}]: ${this.message}`;\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { User } from '../auth/user';\nimport { hardAssert, debugAssert } from '../util/assert';\nimport { Code, FirestoreError } from '../util/error';\nimport {\n FirebaseAuthInternal,\n FirebaseAuthInternalName\n} from '@firebase/auth-interop-types';\nimport { Provider } from '@firebase/component';\nimport { logDebug } from '../util/log';\n\n// TODO(mikelehen): This should be split into multiple files and probably\n// moved to an auth/ folder to match other platforms.\n\nexport interface FirstPartyCredentialsSettings {\n type: 'gapi';\n client: unknown;\n sessionIndex: string;\n}\n\nexport interface ProviderCredentialsSettings {\n type: 'provider';\n client: CredentialsProvider;\n}\n\n/** Settings for private credentials */\nexport type CredentialsSettings =\n | FirstPartyCredentialsSettings\n | ProviderCredentialsSettings;\n\nexport type TokenType = 'OAuth' | 'FirstParty';\nexport interface Token {\n /** Type of token. */\n type: TokenType;\n\n /**\n * The user with which the token is associated (used for persisting user\n * state on disk, etc.).\n */\n user: User;\n\n /** Extra header values to be passed along with a request */\n authHeaders: { [header: string]: string };\n}\n\nexport class OAuthToken implements Token {\n type = 'OAuth' as TokenType;\n authHeaders: { [header: string]: string };\n constructor(value: string, public user: User) {\n this.authHeaders = {};\n // Set the headers using Object Literal notation to avoid minification\n this.authHeaders['Authorization'] = `Bearer ${value}`;\n }\n}\n\n/**\n * A Listener for credential change events. The listener should fetch a new\n * token and may need to invalidate other state if the current user has also\n * changed.\n */\nexport type CredentialChangeListener = (user: User) => void;\n\n/**\n * Provides methods for getting the uid and token for the current user and\n * listening for changes.\n */\nexport interface CredentialsProvider {\n /** Requests a token for the current user. */\n getToken(): Promise;\n\n /**\n * Marks the last retrieved token as invalid, making the next GetToken request\n * force-refresh the token.\n */\n invalidateToken(): void;\n\n /**\n * Specifies a listener to be notified of credential changes\n * (sign-in / sign-out, token changes). It is immediately called once with the\n * initial user.\n */\n setChangeListener(changeListener: CredentialChangeListener): void;\n\n /** Removes the previously-set change listener. */\n removeChangeListener(): void;\n}\n\n/** A CredentialsProvider that always yields an empty token. */\nexport class EmptyCredentialsProvider implements CredentialsProvider {\n /**\n * Stores the listener registered with setChangeListener()\n * This isn't actually necessary since the UID never changes, but we use this\n * to verify the listen contract is adhered to in tests.\n */\n private changeListener: CredentialChangeListener | null = null;\n\n getToken(): Promise {\n return Promise.resolve(null);\n }\n\n invalidateToken(): void {}\n\n setChangeListener(changeListener: CredentialChangeListener): void {\n debugAssert(\n !this.changeListener,\n 'Can only call setChangeListener() once.'\n );\n this.changeListener = changeListener;\n // Fire with initial user.\n changeListener(User.UNAUTHENTICATED);\n }\n\n removeChangeListener(): void {\n debugAssert(\n this.changeListener !== null,\n 'removeChangeListener() when no listener registered'\n );\n this.changeListener = null;\n }\n}\n\nexport class FirebaseCredentialsProvider implements CredentialsProvider {\n /**\n * The auth token listener registered with FirebaseApp, retained here so we\n * can unregister it.\n */\n private tokenListener: ((token: string | null) => void) | null = null;\n\n /** Tracks the current User. */\n private currentUser: User = User.UNAUTHENTICATED;\n private receivedInitialUser: boolean = false;\n\n /**\n * Counter used to detect if the token changed while a getToken request was\n * outstanding.\n */\n private tokenCounter = 0;\n\n /** The listener registered with setChangeListener(). */\n private changeListener: CredentialChangeListener | null = null;\n\n private forceRefresh = false;\n\n private auth: FirebaseAuthInternal | null;\n\n constructor(authProvider: Provider) {\n this.tokenListener = () => {\n this.tokenCounter++;\n this.currentUser = this.getUser();\n this.receivedInitialUser = true;\n if (this.changeListener) {\n this.changeListener(this.currentUser);\n }\n };\n\n this.tokenCounter = 0;\n\n this.auth = authProvider.getImmediate({ optional: true });\n\n if (this.auth) {\n this.auth.addAuthTokenListener(this.tokenListener!);\n } else {\n // if auth is not available, invoke tokenListener once with null token\n this.tokenListener(null);\n authProvider.get().then(\n auth => {\n this.auth = auth;\n if (this.tokenListener) {\n // tokenListener can be removed by removeChangeListener()\n this.auth.addAuthTokenListener(this.tokenListener);\n }\n },\n () => {\n /* this.authProvider.get() never rejects */\n }\n );\n }\n }\n\n getToken(): Promise {\n debugAssert(\n this.tokenListener != null,\n 'getToken cannot be called after listener removed.'\n );\n\n // Take note of the current value of the tokenCounter so that this method\n // can fail (with an ABORTED error) if there is a token change while the\n // request is outstanding.\n const initialTokenCounter = this.tokenCounter;\n const forceRefresh = this.forceRefresh;\n this.forceRefresh = false;\n\n if (!this.auth) {\n return Promise.resolve(null);\n }\n\n return this.auth.getToken(forceRefresh).then(tokenData => {\n // Cancel the request since the token changed while the request was\n // outstanding so the response is potentially for a previous user (which\n // user, we can't be sure).\n if (this.tokenCounter !== initialTokenCounter) {\n logDebug(\n 'FirebaseCredentialsProvider',\n 'getToken aborted due to token change.'\n );\n return this.getToken();\n } else {\n if (tokenData) {\n hardAssert(\n typeof tokenData.accessToken === 'string',\n 'Invalid tokenData returned from getToken():' + tokenData\n );\n return new OAuthToken(tokenData.accessToken, this.currentUser);\n } else {\n return null;\n }\n }\n });\n }\n\n invalidateToken(): void {\n this.forceRefresh = true;\n }\n\n setChangeListener(changeListener: CredentialChangeListener): void {\n debugAssert(\n !this.changeListener,\n 'Can only call setChangeListener() once.'\n );\n this.changeListener = changeListener;\n\n // Fire the initial event\n if (this.receivedInitialUser) {\n changeListener(this.currentUser);\n }\n }\n\n removeChangeListener(): void {\n debugAssert(\n this.tokenListener != null,\n 'removeChangeListener() called twice'\n );\n debugAssert(\n this.changeListener !== null,\n 'removeChangeListener() called when no listener registered'\n );\n\n if (this.auth) {\n this.auth.removeAuthTokenListener(this.tokenListener!);\n }\n this.tokenListener = null;\n this.changeListener = null;\n }\n\n // Auth.getUid() can return null even with a user logged in. It is because\n // getUid() is synchronous, but the auth code populating Uid is asynchronous.\n // This method should only be called in the AuthTokenListener callback\n // to guarantee to get the actual user.\n private getUser(): User {\n const currentUid = this.auth && this.auth.getUid();\n hardAssert(\n currentUid === null || typeof currentUid === 'string',\n 'Received invalid UID: ' + currentUid\n );\n return new User(currentUid);\n }\n}\n\n// Manual type definition for the subset of Gapi we use.\ninterface Gapi {\n auth: {\n getAuthHeaderValueForFirstParty: (\n userIdentifiers: Array<{ [key: string]: string }>\n ) => string | null;\n };\n}\n\n/*\n * FirstPartyToken provides a fresh token each time its value\n * is requested, because if the token is too old, requests will be rejected.\n * Technically this may no longer be necessary since the SDK should gracefully\n * recover from unauthenticated errors (see b/33147818 for context), but it's\n * safer to keep the implementation as-is.\n */\nexport class FirstPartyToken implements Token {\n type = 'FirstParty' as TokenType;\n user = User.FIRST_PARTY;\n\n constructor(private gapi: Gapi, private sessionIndex: string) {}\n\n get authHeaders(): { [header: string]: string } {\n const headers: { [header: string]: string } = {\n 'X-Goog-AuthUser': this.sessionIndex\n };\n const authHeader = this.gapi.auth.getAuthHeaderValueForFirstParty([]);\n if (authHeader) {\n headers['Authorization'] = authHeader;\n }\n return headers;\n }\n}\n\n/*\n * Provides user credentials required for the Firestore JavaScript SDK\n * to authenticate the user, using technique that is only available\n * to applications hosted by Google.\n */\nexport class FirstPartyCredentialsProvider implements CredentialsProvider {\n constructor(private gapi: Gapi, private sessionIndex: string) {}\n\n getToken(): Promise {\n return Promise.resolve(new FirstPartyToken(this.gapi, this.sessionIndex));\n }\n\n setChangeListener(changeListener: CredentialChangeListener): void {\n // Fire with initial uid.\n changeListener(User.FIRST_PARTY);\n }\n\n removeChangeListener(): void {}\n\n invalidateToken(): void {}\n}\n\n/**\n * Builds a CredentialsProvider depending on the type of\n * the credentials passed in.\n */\nexport function makeCredentialsProvider(\n credentials?: CredentialsSettings\n): CredentialsProvider {\n if (!credentials) {\n return new EmptyCredentialsProvider();\n }\n\n switch (credentials.type) {\n case 'gapi':\n const client = credentials.client as Gapi;\n // Make sure this really is a Gapi client.\n hardAssert(\n !!(\n typeof client === 'object' &&\n client !== null &&\n client['auth'] &&\n client['auth']['getAuthHeaderValueForFirstParty']\n ),\n 'unexpected gapi interface'\n );\n return new FirstPartyCredentialsProvider(\n client,\n credentials.sessionIndex || '0'\n );\n\n case 'provider':\n return credentials.client;\n\n default:\n throw new FirestoreError(\n Code.INVALID_ARGUMENT,\n 'makeCredentialsProvider failed due to invalid credential type'\n );\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { Code, FirestoreError } from '../util/error';\nimport { primitiveComparator } from '../util/misc';\n\n// The earlist date supported by Firestore timestamps (0001-01-01T00:00:00Z).\nconst MIN_SECONDS = -62135596800;\n\nexport class Timestamp {\n static now(): Timestamp {\n return Timestamp.fromMillis(Date.now());\n }\n\n static fromDate(date: Date): Timestamp {\n return Timestamp.fromMillis(date.getTime());\n }\n\n static fromMillis(milliseconds: number): Timestamp {\n const seconds = Math.floor(milliseconds / 1000);\n const nanos = (milliseconds - seconds * 1000) * 1e6;\n return new Timestamp(seconds, nanos);\n }\n\n constructor(readonly seconds: number, readonly nanoseconds: number) {\n if (nanoseconds < 0) {\n throw new FirestoreError(\n Code.INVALID_ARGUMENT,\n 'Timestamp nanoseconds out of range: ' + nanoseconds\n );\n }\n if (nanoseconds >= 1e9) {\n throw new FirestoreError(\n Code.INVALID_ARGUMENT,\n 'Timestamp nanoseconds out of range: ' + nanoseconds\n );\n }\n if (seconds < MIN_SECONDS) {\n throw new FirestoreError(\n Code.INVALID_ARGUMENT,\n 'Timestamp seconds out of range: ' + seconds\n );\n }\n // This will break in the year 10,000.\n if (seconds >= 253402300800) {\n throw new FirestoreError(\n Code.INVALID_ARGUMENT,\n 'Timestamp seconds out of range: ' + seconds\n );\n }\n }\n\n toDate(): Date {\n return new Date(this.toMillis());\n }\n\n toMillis(): number {\n return this.seconds * 1000 + this.nanoseconds / 1e6;\n }\n\n _compareTo(other: Timestamp): number {\n if (this.seconds === other.seconds) {\n return primitiveComparator(this.nanoseconds, other.nanoseconds);\n }\n return primitiveComparator(this.seconds, other.seconds);\n }\n\n isEqual(other: Timestamp): boolean {\n return (\n other.seconds === this.seconds && other.nanoseconds === this.nanoseconds\n );\n }\n\n toString(): string {\n return (\n 'Timestamp(seconds=' +\n this.seconds +\n ', nanoseconds=' +\n this.nanoseconds +\n ')'\n );\n }\n\n valueOf(): string {\n // This method returns a string of the form . where is\n // translated to have a non-negative value and both and are left-padded\n // with zeroes to be a consistent length. Strings with this format then have a lexiographical\n // ordering that matches the expected ordering. The translation is done to avoid\n // having a leading negative sign (i.e. a leading '-' character) in its string representation,\n // which would affect its lexiographical ordering.\n const adjustedSeconds = this.seconds - MIN_SECONDS;\n // Note: Up to 12 decimal digits are required to represent all valid 'seconds' values.\n const formattedSeconds = String(adjustedSeconds).padStart(12, '0');\n const formattedNanoseconds = String(this.nanoseconds).padStart(9, '0');\n return formattedSeconds + '.' + formattedNanoseconds;\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { Timestamp } from '../api/timestamp';\n\n/**\n * A version of a document in Firestore. This corresponds to the version\n * timestamp, such as update_time or read_time.\n */\nexport class SnapshotVersion {\n static fromTimestamp(value: Timestamp): SnapshotVersion {\n return new SnapshotVersion(value);\n }\n\n static min(): SnapshotVersion {\n return new SnapshotVersion(new Timestamp(0, 0));\n }\n\n private constructor(private timestamp: Timestamp) {}\n\n compareTo(other: SnapshotVersion): number {\n return this.timestamp._compareTo(other.timestamp);\n }\n\n isEqual(other: SnapshotVersion): boolean {\n return this.timestamp.isEqual(other.timestamp);\n }\n\n /** Returns a number representation of the version for use in spec tests. */\n toMicroseconds(): number {\n // Convert to microseconds.\n return this.timestamp.seconds * 1e6 + this.timestamp.nanoseconds / 1000;\n }\n\n toString(): string {\n return 'SnapshotVersion(' + this.timestamp.toString() + ')';\n }\n\n toTimestamp(): Timestamp {\n return this.timestamp;\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { debugAssert, fail } from '../util/assert';\nimport { Code, FirestoreError } from '../util/error';\n\nexport const DOCUMENT_KEY_NAME = '__name__';\n\n/**\n * Path represents an ordered sequence of string segments.\n */\nabstract class BasePath> {\n private segments: string[];\n private offset: number;\n private len: number;\n\n constructor(segments: string[], offset?: number, length?: number) {\n if (offset === undefined) {\n offset = 0;\n } else if (offset > segments.length) {\n fail('offset ' + offset + ' out of range ' + segments.length);\n }\n\n if (length === undefined) {\n length = segments.length - offset;\n } else if (length > segments.length - offset) {\n fail('length ' + length + ' out of range ' + (segments.length - offset));\n }\n this.segments = segments;\n this.offset = offset;\n this.len = length;\n }\n\n /**\n * Abstract constructor method to construct an instance of B with the given\n * parameters.\n */\n protected abstract construct(\n segments: string[],\n offset?: number,\n length?: number\n ): B;\n\n /**\n * Returns a String representation.\n *\n * Implementing classes are required to provide deterministic implementations as\n * the String representation is used to obtain canonical Query IDs.\n */\n abstract toString(): string;\n\n get length(): number {\n return this.len;\n }\n\n isEqual(other: B): boolean {\n return BasePath.comparator(this, other) === 0;\n }\n\n child(nameOrPath: string | B): B {\n const segments = this.segments.slice(this.offset, this.limit());\n if (nameOrPath instanceof BasePath) {\n nameOrPath.forEach(segment => {\n segments.push(segment);\n });\n } else {\n segments.push(nameOrPath);\n }\n return this.construct(segments);\n }\n\n /** The index of one past the last segment of the path. */\n private limit(): number {\n return this.offset + this.length;\n }\n\n popFirst(size?: number): B {\n size = size === undefined ? 1 : size;\n debugAssert(\n this.length >= size,\n \"Can't call popFirst() with less segments\"\n );\n return this.construct(\n this.segments,\n this.offset + size,\n this.length - size\n );\n }\n\n popLast(): B {\n debugAssert(!this.isEmpty(), \"Can't call popLast() on empty path\");\n return this.construct(this.segments, this.offset, this.length - 1);\n }\n\n firstSegment(): string {\n debugAssert(!this.isEmpty(), \"Can't call firstSegment() on empty path\");\n return this.segments[this.offset];\n }\n\n lastSegment(): string {\n return this.get(this.length - 1);\n }\n\n get(index: number): string {\n debugAssert(index < this.length, 'Index out of range');\n return this.segments[this.offset + index];\n }\n\n isEmpty(): boolean {\n return this.length === 0;\n }\n\n isPrefixOf(other: this): boolean {\n if (other.length < this.length) {\n return false;\n }\n\n for (let i = 0; i < this.length; i++) {\n if (this.get(i) !== other.get(i)) {\n return false;\n }\n }\n\n return true;\n }\n\n isImmediateParentOf(potentialChild: this): boolean {\n if (this.length + 1 !== potentialChild.length) {\n return false;\n }\n\n for (let i = 0; i < this.length; i++) {\n if (this.get(i) !== potentialChild.get(i)) {\n return false;\n }\n }\n\n return true;\n }\n\n forEach(fn: (segment: string) => void): void {\n for (let i = this.offset, end = this.limit(); i < end; i++) {\n fn(this.segments[i]);\n }\n }\n\n toArray(): string[] {\n return this.segments.slice(this.offset, this.limit());\n }\n\n static comparator>(\n p1: BasePath,\n p2: BasePath\n ): number {\n const len = Math.min(p1.length, p2.length);\n for (let i = 0; i < len; i++) {\n const left = p1.get(i);\n const right = p2.get(i);\n if (left < right) {\n return -1;\n }\n if (left > right) {\n return 1;\n }\n }\n if (p1.length < p2.length) {\n return -1;\n }\n if (p1.length > p2.length) {\n return 1;\n }\n return 0;\n }\n}\n\n/**\n * A slash-separated path for navigating resources (documents and collections)\n * within Firestore.\n */\nexport class ResourcePath extends BasePath {\n protected construct(\n segments: string[],\n offset?: number,\n length?: number\n ): ResourcePath {\n return new ResourcePath(segments, offset, length);\n }\n\n canonicalString(): string {\n // NOTE: The client is ignorant of any path segments containing escape\n // sequences (e.g. __id123__) and just passes them through raw (they exist\n // for legacy reasons and should not be used frequently).\n\n return this.toArray().join('/');\n }\n\n toString(): string {\n return this.canonicalString();\n }\n\n /**\n * Creates a resource path from the given slash-delimited string.\n */\n static fromString(path: string): ResourcePath {\n // NOTE: The client is ignorant of any path segments containing escape\n // sequences (e.g. __id123__) and just passes them through raw (they exist\n // for legacy reasons and should not be used frequently).\n\n if (path.indexOf('//') >= 0) {\n throw new FirestoreError(\n Code.INVALID_ARGUMENT,\n `Invalid path (${path}). Paths must not contain // in them.`\n );\n }\n\n // We may still have an empty segment at the beginning or end if they had a\n // leading or trailing slash (which we allow).\n const segments = path.split('/').filter(segment => segment.length > 0);\n\n return new ResourcePath(segments);\n }\n\n static EMPTY_PATH = new ResourcePath([]);\n}\n\nconst identifierRegExp = /^[_a-zA-Z][_a-zA-Z0-9]*$/;\n\n/** A dot-separated path for navigating sub-objects within a document. */\nexport class FieldPath extends BasePath {\n protected construct(\n segments: string[],\n offset?: number,\n length?: number\n ): FieldPath {\n return new FieldPath(segments, offset, length);\n }\n\n /**\n * Returns true if the string could be used as a segment in a field path\n * without escaping.\n */\n private static isValidIdentifier(segment: string): boolean {\n return identifierRegExp.test(segment);\n }\n\n canonicalString(): string {\n return this.toArray()\n .map(str => {\n str = str.replace('\\\\', '\\\\\\\\').replace('`', '\\\\`');\n if (!FieldPath.isValidIdentifier(str)) {\n str = '`' + str + '`';\n }\n return str;\n })\n .join('.');\n }\n\n toString(): string {\n return this.canonicalString();\n }\n\n /**\n * Returns true if this field references the key of a document.\n */\n isKeyField(): boolean {\n return this.length === 1 && this.get(0) === DOCUMENT_KEY_NAME;\n }\n\n /**\n * The field designating the key of a document.\n */\n static keyField(): FieldPath {\n return new FieldPath([DOCUMENT_KEY_NAME]);\n }\n\n /**\n * Parses a field string from the given server-formatted string.\n *\n * - Splitting the empty string is not allowed (for now at least).\n * - Empty segments within the string (e.g. if there are two consecutive\n * separators) are not allowed.\n *\n * TODO(b/37244157): we should make this more strict. Right now, it allows\n * non-identifier path components, even if they aren't escaped.\n */\n static fromServerFormat(path: string): FieldPath {\n const segments: string[] = [];\n let current = '';\n let i = 0;\n\n const addCurrentSegment = (): void => {\n if (current.length === 0) {\n throw new FirestoreError(\n Code.INVALID_ARGUMENT,\n `Invalid field path (${path}). Paths must not be empty, begin ` +\n `with '.', end with '.', or contain '..'`\n );\n }\n segments.push(current);\n current = '';\n };\n\n let inBackticks = false;\n\n while (i < path.length) {\n const c = path[i];\n if (c === '\\\\') {\n if (i + 1 === path.length) {\n throw new FirestoreError(\n Code.INVALID_ARGUMENT,\n 'Path has trailing escape character: ' + path\n );\n }\n const next = path[i + 1];\n if (!(next === '\\\\' || next === '.' || next === '`')) {\n throw new FirestoreError(\n Code.INVALID_ARGUMENT,\n 'Path has invalid escape sequence: ' + path\n );\n }\n current += next;\n i += 2;\n } else if (c === '`') {\n inBackticks = !inBackticks;\n i++;\n } else if (c === '.' && !inBackticks) {\n addCurrentSegment();\n i++;\n } else {\n current += c;\n i++;\n }\n }\n addCurrentSegment();\n\n if (inBackticks) {\n throw new FirestoreError(\n Code.INVALID_ARGUMENT,\n 'Unterminated ` in path: ' + path\n );\n }\n\n return new FieldPath(segments);\n }\n\n static EMPTY_PATH = new FieldPath([]);\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { debugAssert } from '../util/assert';\n\nimport { ResourcePath } from './path';\n\nexport class DocumentKey {\n constructor(readonly path: ResourcePath) {\n debugAssert(\n DocumentKey.isDocumentKey(path),\n 'Invalid DocumentKey with an odd number of segments: ' +\n path.toArray().join('/')\n );\n }\n\n static fromName(name: string): DocumentKey {\n return new DocumentKey(ResourcePath.fromString(name).popFirst(5));\n }\n\n /** Returns true if the document is in the specified collectionId. */\n hasCollectionId(collectionId: string): boolean {\n return (\n this.path.length >= 2 &&\n this.path.get(this.path.length - 2) === collectionId\n );\n }\n\n isEqual(other: DocumentKey | null): boolean {\n return (\n other !== null && ResourcePath.comparator(this.path, other.path) === 0\n );\n }\n\n toString(): string {\n return this.path.toString();\n }\n\n static EMPTY = new DocumentKey(new ResourcePath([]));\n\n static comparator(k1: DocumentKey, k2: DocumentKey): number {\n return ResourcePath.comparator(k1.path, k2.path);\n }\n\n static isDocumentKey(path: ResourcePath): boolean {\n return path.length % 2 === 0;\n }\n\n /**\n * Creates and returns a new document key with the given segments.\n *\n * @param segments The segments of the path to the document\n * @return A new instance of DocumentKey\n */\n static fromSegments(segments: string[]): DocumentKey {\n return new DocumentKey(new ResourcePath(segments.slice()));\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { debugAssert } from './assert';\n\nexport interface Dict {\n [stringKey: string]: V;\n}\n\nexport function objectSize(obj: object): number {\n let count = 0;\n for (const key in obj) {\n if (Object.prototype.hasOwnProperty.call(obj, key)) {\n count++;\n }\n }\n return count;\n}\n\nexport function forEach(\n obj: Dict,\n fn: (key: string, val: V) => void\n): void {\n for (const key in obj) {\n if (Object.prototype.hasOwnProperty.call(obj, key)) {\n fn(key, obj[key]);\n }\n }\n}\n\nexport function isEmpty(obj: Dict): boolean {\n debugAssert(\n obj != null && typeof obj === 'object',\n 'isEmpty() expects object parameter.'\n );\n for (const key in obj) {\n if (Object.prototype.hasOwnProperty.call(obj, key)) {\n return false;\n }\n }\n return true;\n}\n","/**\n * @license\n * Copyright 2020 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { PlatformSupport } from '../platform/platform';\nimport { primitiveComparator } from './misc';\n\n/**\n * Immutable class that represents a \"proto\" byte string.\n *\n * Proto byte strings can either be Base64-encoded strings or Uint8Arrays when\n * sent on the wire. This class abstracts away this differentiation by holding\n * the proto byte string in a common class that must be converted into a string\n * before being sent as a proto.\n */\nexport class ByteString {\n static readonly EMPTY_BYTE_STRING = new ByteString('');\n\n private constructor(private readonly binaryString: string) {}\n\n static fromBase64String(base64: string): ByteString {\n const binaryString = PlatformSupport.getPlatform().atob(base64);\n return new ByteString(binaryString);\n }\n\n static fromUint8Array(array: Uint8Array): ByteString {\n const binaryString = binaryStringFromUint8Array(array);\n return new ByteString(binaryString);\n }\n\n toBase64(): string {\n return PlatformSupport.getPlatform().btoa(this.binaryString);\n }\n\n toUint8Array(): Uint8Array {\n return uint8ArrayFromBinaryString(this.binaryString);\n }\n\n approximateByteSize(): number {\n return this.binaryString.length * 2;\n }\n\n compareTo(other: ByteString): number {\n return primitiveComparator(this.binaryString, other.binaryString);\n }\n\n isEqual(other: ByteString): boolean {\n return this.binaryString === other.binaryString;\n }\n}\n\n/**\n * Helper function to convert an Uint8array to a binary string.\n */\nexport function binaryStringFromUint8Array(array: Uint8Array): string {\n let binaryString = '';\n for (let i = 0; i < array.length; ++i) {\n binaryString += String.fromCharCode(array[i]);\n }\n return binaryString;\n}\n\n/**\n * Helper function to convert a binary string to an Uint8Array.\n */\nexport function uint8ArrayFromBinaryString(binaryString: string): Uint8Array {\n const buffer = new Uint8Array(binaryString.length);\n for (let i = 0; i < binaryString.length; i++) {\n buffer[i] = binaryString.charCodeAt(i);\n }\n return buffer;\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\n// An Object whose keys and values are strings.\nexport interface StringMap {\n [key: string]: string;\n}\n\n/**\n * Returns whether a variable is either undefined or null.\n */\nexport function isNullOrUndefined(value: unknown): value is null | undefined {\n return value === null || value === undefined;\n}\n\n/** Returns whether the value represents -0. */\nexport function isNegativeZero(value: number): boolean {\n // Detect if the value is -0.0. Based on polyfill from\n // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/is\n return value === -0 && 1 / value === 1 / -0;\n}\n\n/**\n * Returns whether a value is an integer and in the safe integer range\n * @param value The value to test for being an integer and in the safe range\n */\nexport function isSafeInteger(value: unknown): boolean {\n return (\n typeof value === 'number' &&\n Number.isInteger(value) &&\n !isNegativeZero(value) &&\n value <= Number.MAX_SAFE_INTEGER &&\n value >= Number.MIN_SAFE_INTEGER\n );\n}\n","/**\n * @license\n * Copyright 2020 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport * as api from '../protos/firestore_proto_api';\nimport { Timestamp } from '../api/timestamp';\nimport { normalizeTimestamp } from './values';\n\n/**\n * Represents a locally-applied ServerTimestamp.\n *\n * Server Timestamps are backed by MapValues that contain an internal field\n * `__type__` with a value of `server_timestamp`. The previous value and local\n * write time are stored in its `__previous_value__` and `__local_write_time__`\n * fields respectively.\n *\n * Notes:\n * - ServerTimestampValue instances are created as the result of applying a\n * TransformMutation (see TransformMutation.applyTo()). They can only exist in\n * the local view of a document. Therefore they do not need to be parsed or\n * serialized.\n * - When evaluated locally (e.g. for snapshot.data()), they by default\n * evaluate to `null`. This behavior can be configured by passing custom\n * FieldValueOptions to value().\n * - With respect to other ServerTimestampValues, they sort by their\n * localWriteTime.\n */\n\nconst SERVER_TIMESTAMP_SENTINEL = 'server_timestamp';\nconst TYPE_KEY = '__type__';\nconst PREVIOUS_VALUE_KEY = '__previous_value__';\nconst LOCAL_WRITE_TIME_KEY = '__local_write_time__';\n\nexport function isServerTimestamp(value: api.Value | null): boolean {\n const type = (value?.mapValue?.fields || {})[TYPE_KEY]?.stringValue;\n return type === SERVER_TIMESTAMP_SENTINEL;\n}\n\n/**\n * Creates a new ServerTimestamp proto value (using the internal format).\n */\nexport function serverTimestamp(\n localWriteTime: Timestamp,\n previousValue: api.Value | null\n): api.Value {\n const mapValue: api.MapValue = {\n fields: {\n [TYPE_KEY]: {\n stringValue: SERVER_TIMESTAMP_SENTINEL\n },\n [LOCAL_WRITE_TIME_KEY]: {\n timestampValue: {\n seconds: localWriteTime.seconds,\n nanos: localWriteTime.nanoseconds\n }\n }\n }\n };\n\n if (previousValue) {\n mapValue.fields![PREVIOUS_VALUE_KEY] = previousValue;\n }\n\n return { mapValue };\n}\n\n/**\n * Returns the value of the field before this ServerTimestamp was set.\n *\n * Preserving the previous values allows the user to display the last resoled\n * value until the backend responds with the timestamp.\n */\nexport function getPreviousValue(value: api.Value): api.Value | null {\n const previousValue = value.mapValue!.fields![PREVIOUS_VALUE_KEY];\n\n if (isServerTimestamp(previousValue)) {\n return getPreviousValue(previousValue);\n }\n return previousValue;\n}\n\n/**\n * Returns the local time at which this timestamp was first set.\n */\nexport function getLocalWriteTime(value: api.Value): Timestamp {\n const localWriteTime = normalizeTimestamp(\n value.mapValue!.fields![LOCAL_WRITE_TIME_KEY].timestampValue!\n );\n return new Timestamp(localWriteTime.seconds, localWriteTime.nanos);\n}\n","/**\n * @license\n * Copyright 2020 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport * as api from '../protos/firestore_proto_api';\n\nimport { TypeOrder } from './object_value';\nimport { fail, hardAssert } from '../util/assert';\nimport { forEach, objectSize } from '../util/obj';\nimport { ByteString } from '../util/byte_string';\nimport { isNegativeZero } from '../util/types';\nimport { DocumentKey } from './document_key';\nimport { arrayEquals, primitiveComparator } from '../util/misc';\nimport { DatabaseId } from '../core/database_info';\nimport {\n getLocalWriteTime,\n getPreviousValue,\n isServerTimestamp\n} from './server_timestamps';\n\n// A RegExp matching ISO 8601 UTC timestamps with optional fraction.\nconst ISO_TIMESTAMP_REG_EXP = new RegExp(\n /^\\d{4}-\\d\\d-\\d\\dT\\d\\d:\\d\\d:\\d\\d(?:\\.(\\d+))?Z$/\n);\n\n/** Extracts the backend's type order for the provided value. */\nexport function typeOrder(value: api.Value): TypeOrder {\n if ('nullValue' in value) {\n return TypeOrder.NullValue;\n } else if ('booleanValue' in value) {\n return TypeOrder.BooleanValue;\n } else if ('integerValue' in value || 'doubleValue' in value) {\n return TypeOrder.NumberValue;\n } else if ('timestampValue' in value) {\n return TypeOrder.TimestampValue;\n } else if ('stringValue' in value) {\n return TypeOrder.StringValue;\n } else if ('bytesValue' in value) {\n return TypeOrder.BlobValue;\n } else if ('referenceValue' in value) {\n return TypeOrder.RefValue;\n } else if ('geoPointValue' in value) {\n return TypeOrder.GeoPointValue;\n } else if ('arrayValue' in value) {\n return TypeOrder.ArrayValue;\n } else if ('mapValue' in value) {\n if (isServerTimestamp(value)) {\n return TypeOrder.ServerTimestampValue;\n }\n return TypeOrder.ObjectValue;\n } else {\n return fail('Invalid value type: ' + JSON.stringify(value));\n }\n}\n\n/** Tests `left` and `right` for equality based on the backend semantics. */\nexport function valueEquals(left: api.Value, right: api.Value): boolean {\n const leftType = typeOrder(left);\n const rightType = typeOrder(right);\n if (leftType !== rightType) {\n return false;\n }\n\n switch (leftType) {\n case TypeOrder.NullValue:\n return true;\n case TypeOrder.BooleanValue:\n return left.booleanValue === right.booleanValue;\n case TypeOrder.ServerTimestampValue:\n return getLocalWriteTime(left).isEqual(getLocalWriteTime(right));\n case TypeOrder.TimestampValue:\n return timestampEquals(left, right);\n case TypeOrder.StringValue:\n return left.stringValue === right.stringValue;\n case TypeOrder.BlobValue:\n return blobEquals(left, right);\n case TypeOrder.RefValue:\n return left.referenceValue === right.referenceValue;\n case TypeOrder.GeoPointValue:\n return geoPointEquals(left, right);\n case TypeOrder.NumberValue:\n return numberEquals(left, right);\n case TypeOrder.ArrayValue:\n return arrayEquals(\n left.arrayValue!.values || [],\n right.arrayValue!.values || [],\n valueEquals\n );\n case TypeOrder.ObjectValue:\n return objectEquals(left, right);\n default:\n return fail('Unexpected value type: ' + JSON.stringify(left));\n }\n}\n\nfunction timestampEquals(left: api.Value, right: api.Value): boolean {\n if (\n typeof left.timestampValue === 'string' &&\n typeof right.timestampValue === 'string' &&\n left.timestampValue.length === right.timestampValue.length\n ) {\n // Use string equality for ISO 8601 timestamps\n return left.timestampValue === right.timestampValue;\n }\n\n const leftTimestamp = normalizeTimestamp(left.timestampValue!);\n const rightTimestamp = normalizeTimestamp(right.timestampValue!);\n return (\n leftTimestamp.seconds === rightTimestamp.seconds &&\n leftTimestamp.nanos === rightTimestamp.nanos\n );\n}\n\nfunction geoPointEquals(left: api.Value, right: api.Value): boolean {\n return (\n normalizeNumber(left.geoPointValue!.latitude) ===\n normalizeNumber(right.geoPointValue!.latitude) &&\n normalizeNumber(left.geoPointValue!.longitude) ===\n normalizeNumber(right.geoPointValue!.longitude)\n );\n}\n\nfunction blobEquals(left: api.Value, right: api.Value): boolean {\n return normalizeByteString(left.bytesValue!).isEqual(\n normalizeByteString(right.bytesValue!)\n );\n}\n\nexport function numberEquals(left: api.Value, right: api.Value): boolean {\n if ('integerValue' in left && 'integerValue' in right) {\n return (\n normalizeNumber(left.integerValue) === normalizeNumber(right.integerValue)\n );\n } else if ('doubleValue' in left && 'doubleValue' in right) {\n const n1 = normalizeNumber(left.doubleValue!);\n const n2 = normalizeNumber(right.doubleValue!);\n\n if (n1 === n2) {\n return isNegativeZero(n1) === isNegativeZero(n2);\n } else {\n return isNaN(n1) && isNaN(n2);\n }\n }\n\n return false;\n}\n\nfunction objectEquals(left: api.Value, right: api.Value): boolean {\n const leftMap = left.mapValue!.fields || {};\n const rightMap = right.mapValue!.fields || {};\n\n if (objectSize(leftMap) !== objectSize(rightMap)) {\n return false;\n }\n\n for (const key in leftMap) {\n if (leftMap.hasOwnProperty(key)) {\n if (\n rightMap[key] === undefined ||\n !valueEquals(leftMap[key], rightMap[key])\n ) {\n return false;\n }\n }\n }\n return true;\n}\n\n/** Returns true if the ArrayValue contains the specified element. */\nexport function arrayValueContains(\n haystack: api.ArrayValue,\n needle: api.Value\n): boolean {\n return (\n (haystack.values || []).find(v => valueEquals(v, needle)) !== undefined\n );\n}\n\nexport function valueCompare(left: api.Value, right: api.Value): number {\n const leftType = typeOrder(left);\n const rightType = typeOrder(right);\n\n if (leftType !== rightType) {\n return primitiveComparator(leftType, rightType);\n }\n\n switch (leftType) {\n case TypeOrder.NullValue:\n return 0;\n case TypeOrder.BooleanValue:\n return primitiveComparator(left.booleanValue!, right.booleanValue!);\n case TypeOrder.NumberValue:\n return compareNumbers(left, right);\n case TypeOrder.TimestampValue:\n return compareTimestamps(left.timestampValue!, right.timestampValue!);\n case TypeOrder.ServerTimestampValue:\n return compareTimestamps(\n getLocalWriteTime(left),\n getLocalWriteTime(right)\n );\n case TypeOrder.StringValue:\n return primitiveComparator(left.stringValue!, right.stringValue!);\n case TypeOrder.BlobValue:\n return compareBlobs(left.bytesValue!, right.bytesValue!);\n case TypeOrder.RefValue:\n return compareReferences(left.referenceValue!, right.referenceValue!);\n case TypeOrder.GeoPointValue:\n return compareGeoPoints(left.geoPointValue!, right.geoPointValue!);\n case TypeOrder.ArrayValue:\n return compareArrays(left.arrayValue!, right.arrayValue!);\n case TypeOrder.ObjectValue:\n return compareMaps(left.mapValue!, right.mapValue!);\n default:\n throw fail('Invalid value type: ' + leftType);\n }\n}\n\nfunction compareNumbers(left: api.Value, right: api.Value): number {\n const leftNumber = normalizeNumber(left.integerValue || left.doubleValue);\n const rightNumber = normalizeNumber(right.integerValue || right.doubleValue);\n\n if (leftNumber < rightNumber) {\n return -1;\n } else if (leftNumber > rightNumber) {\n return 1;\n } else if (leftNumber === rightNumber) {\n return 0;\n } else {\n // one or both are NaN.\n if (isNaN(leftNumber)) {\n return isNaN(rightNumber) ? 0 : -1;\n } else {\n return 1;\n }\n }\n}\n\nfunction compareTimestamps(left: api.Timestamp, right: api.Timestamp): number {\n if (\n typeof left === 'string' &&\n typeof right === 'string' &&\n left.length === right.length\n ) {\n return primitiveComparator(left, right);\n }\n\n const leftTimestamp = normalizeTimestamp(left);\n const rightTimestamp = normalizeTimestamp(right);\n\n const comparison = primitiveComparator(\n leftTimestamp.seconds,\n rightTimestamp.seconds\n );\n if (comparison !== 0) {\n return comparison;\n }\n return primitiveComparator(leftTimestamp.nanos, rightTimestamp.nanos);\n}\n\nfunction compareReferences(leftPath: string, rightPath: string): number {\n const leftSegments = leftPath.split('/');\n const rightSegments = rightPath.split('/');\n for (let i = 0; i < leftSegments.length && i < rightSegments.length; i++) {\n const comparison = primitiveComparator(leftSegments[i], rightSegments[i]);\n if (comparison !== 0) {\n return comparison;\n }\n }\n return primitiveComparator(leftSegments.length, rightSegments.length);\n}\n\nfunction compareGeoPoints(left: api.LatLng, right: api.LatLng): number {\n const comparison = primitiveComparator(\n normalizeNumber(left.latitude),\n normalizeNumber(right.latitude)\n );\n if (comparison !== 0) {\n return comparison;\n }\n return primitiveComparator(\n normalizeNumber(left.longitude),\n normalizeNumber(right.longitude)\n );\n}\n\nfunction compareBlobs(\n left: string | Uint8Array,\n right: string | Uint8Array\n): number {\n const leftBytes = normalizeByteString(left);\n const rightBytes = normalizeByteString(right);\n return leftBytes.compareTo(rightBytes);\n}\n\nfunction compareArrays(left: api.ArrayValue, right: api.ArrayValue): number {\n const leftArray = left.values || [];\n const rightArray = right.values || [];\n\n for (let i = 0; i < leftArray.length && i < rightArray.length; ++i) {\n const compare = valueCompare(leftArray[i], rightArray[i]);\n if (compare) {\n return compare;\n }\n }\n return primitiveComparator(leftArray.length, rightArray.length);\n}\n\nfunction compareMaps(left: api.MapValue, right: api.MapValue): number {\n const leftMap = left.fields || {};\n const leftKeys = Object.keys(leftMap);\n const rightMap = right.fields || {};\n const rightKeys = Object.keys(rightMap);\n\n // Even though MapValues are likely sorted correctly based on their insertion\n // order (e.g. when received from the backend), local modifications can bring\n // elements out of order. We need to re-sort the elements to ensure that\n // canonical IDs are independent of insertion order.\n leftKeys.sort();\n rightKeys.sort();\n\n for (let i = 0; i < leftKeys.length && i < rightKeys.length; ++i) {\n const keyCompare = primitiveComparator(leftKeys[i], rightKeys[i]);\n if (keyCompare !== 0) {\n return keyCompare;\n }\n const compare = valueCompare(leftMap[leftKeys[i]], rightMap[rightKeys[i]]);\n if (compare !== 0) {\n return compare;\n }\n }\n\n return primitiveComparator(leftKeys.length, rightKeys.length);\n}\n\n/**\n * Generates the canonical ID for the provided field value (as used in Target\n * serialization).\n */\nexport function canonicalId(value: api.Value): string {\n return canonifyValue(value);\n}\n\nfunction canonifyValue(value: api.Value): string {\n if ('nullValue' in value) {\n return 'null';\n } else if ('booleanValue' in value) {\n return '' + value.booleanValue!;\n } else if ('integerValue' in value) {\n return '' + value.integerValue!;\n } else if ('doubleValue' in value) {\n return '' + value.doubleValue!;\n } else if ('timestampValue' in value) {\n return canonifyTimestamp(value.timestampValue!);\n } else if ('stringValue' in value) {\n return value.stringValue!;\n } else if ('bytesValue' in value) {\n return canonifyByteString(value.bytesValue!);\n } else if ('referenceValue' in value) {\n return canonifyReference(value.referenceValue!);\n } else if ('geoPointValue' in value) {\n return canonifyGeoPoint(value.geoPointValue!);\n } else if ('arrayValue' in value) {\n return canonifyArray(value.arrayValue!);\n } else if ('mapValue' in value) {\n return canonifyMap(value.mapValue!);\n } else {\n return fail('Invalid value type: ' + JSON.stringify(value));\n }\n}\n\nfunction canonifyByteString(byteString: string | Uint8Array): string {\n return normalizeByteString(byteString).toBase64();\n}\n\nfunction canonifyTimestamp(timestamp: api.Timestamp): string {\n const normalizedTimestamp = normalizeTimestamp(timestamp);\n return `time(${normalizedTimestamp.seconds},${normalizedTimestamp.nanos})`;\n}\n\nfunction canonifyGeoPoint(geoPoint: api.LatLng): string {\n return `geo(${geoPoint.latitude},${geoPoint.longitude})`;\n}\n\nfunction canonifyReference(referenceValue: string): string {\n return DocumentKey.fromName(referenceValue).toString();\n}\n\nfunction canonifyMap(mapValue: api.MapValue): string {\n // Iteration order in JavaScript is not guaranteed. To ensure that we generate\n // matching canonical IDs for identical maps, we need to sort the keys.\n const sortedKeys = Object.keys(mapValue.fields || {}).sort();\n\n let result = '{';\n let first = true;\n for (const key of sortedKeys) {\n if (!first) {\n result += ',';\n } else {\n first = false;\n }\n result += `${key}:${canonifyValue(mapValue.fields![key])}`;\n }\n return result + '}';\n}\n\nfunction canonifyArray(arrayValue: api.ArrayValue): string {\n let result = '[';\n let first = true;\n for (const value of arrayValue.values || []) {\n if (!first) {\n result += ',';\n } else {\n first = false;\n }\n result += canonifyValue(value);\n }\n return result + ']';\n}\n\n/**\n * Returns an approximate (and wildly inaccurate) in-memory size for the field\n * value.\n *\n * The memory size takes into account only the actual user data as it resides\n * in memory and ignores object overhead.\n */\nexport function estimateByteSize(value: api.Value): number {\n switch (typeOrder(value)) {\n case TypeOrder.NullValue:\n return 4;\n case TypeOrder.BooleanValue:\n return 4;\n case TypeOrder.NumberValue:\n return 8;\n case TypeOrder.TimestampValue:\n // Timestamps are made up of two distinct numbers (seconds + nanoseconds)\n return 16;\n case TypeOrder.ServerTimestampValue:\n const previousValue = getPreviousValue(value);\n return previousValue ? 16 + estimateByteSize(previousValue) : 16;\n case TypeOrder.StringValue:\n // See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures:\n // \"JavaScript's String type is [...] a set of elements of 16-bit unsigned\n // integer values\"\n return value.stringValue!.length * 2;\n case TypeOrder.BlobValue:\n return normalizeByteString(value.bytesValue!).approximateByteSize();\n case TypeOrder.RefValue:\n return value.referenceValue!.length;\n case TypeOrder.GeoPointValue:\n // GeoPoints are made up of two distinct numbers (latitude + longitude)\n return 16;\n case TypeOrder.ArrayValue:\n return estimateArrayByteSize(value.arrayValue!);\n case TypeOrder.ObjectValue:\n return estimateMapByteSize(value.mapValue!);\n default:\n throw fail('Invalid value type: ' + JSON.stringify(value));\n }\n}\n\nfunction estimateMapByteSize(mapValue: api.MapValue): number {\n let size = 0;\n forEach(mapValue.fields || {}, (key, val) => {\n size += key.length + estimateByteSize(val);\n });\n return size;\n}\n\nfunction estimateArrayByteSize(arrayValue: api.ArrayValue): number {\n return (arrayValue.values || []).reduce(\n (previousSize, value) => previousSize + estimateByteSize(value),\n 0\n );\n}\n\n/**\n * Converts the possible Proto values for a timestamp value into a \"seconds and\n * nanos\" representation.\n */\nexport function normalizeTimestamp(\n date: api.Timestamp\n): { seconds: number; nanos: number } {\n hardAssert(!!date, 'Cannot normalize null or undefined timestamp.');\n\n // The json interface (for the browser) will return an iso timestamp string,\n // while the proto js library (for node) will return a\n // google.protobuf.Timestamp instance.\n if (typeof date === 'string') {\n // The date string can have higher precision (nanos) than the Date class\n // (millis), so we do some custom parsing here.\n\n // Parse the nanos right out of the string.\n let nanos = 0;\n const fraction = ISO_TIMESTAMP_REG_EXP.exec(date);\n hardAssert(!!fraction, 'invalid timestamp: ' + date);\n if (fraction[1]) {\n // Pad the fraction out to 9 digits (nanos).\n let nanoStr = fraction[1];\n nanoStr = (nanoStr + '000000000').substr(0, 9);\n nanos = Number(nanoStr);\n }\n\n // Parse the date to get the seconds.\n const parsedDate = new Date(date);\n const seconds = Math.floor(parsedDate.getTime() / 1000);\n\n return { seconds, nanos };\n } else {\n // TODO(b/37282237): Use strings for Proto3 timestamps\n // assert(!this.options.useProto3Json,\n // 'The timestamp instance format requires Proto JS.');\n const seconds = normalizeNumber(date.seconds);\n const nanos = normalizeNumber(date.nanos);\n return { seconds, nanos };\n }\n}\n\n/**\n * Converts the possible Proto types for numbers into a JavaScript number.\n * Returns 0 if the value is not numeric.\n */\nexport function normalizeNumber(value: number | string | undefined): number {\n // TODO(bjornick): Handle int64 greater than 53 bits.\n if (typeof value === 'number') {\n return value;\n } else if (typeof value === 'string') {\n return Number(value);\n } else {\n return 0;\n }\n}\n\n/** Converts the possible Proto types for Blobs into a ByteString. */\nexport function normalizeByteString(blob: string | Uint8Array): ByteString {\n if (typeof blob === 'string') {\n return ByteString.fromBase64String(blob);\n } else {\n return ByteString.fromUint8Array(blob);\n }\n}\n\n/** Returns a reference value for the provided database and key. */\nexport function refValue(databaseId: DatabaseId, key: DocumentKey): api.Value {\n return {\n referenceValue: `projects/${databaseId.projectId}/databases/${\n databaseId.database\n }/documents/${key.path.canonicalString()}`\n };\n}\n\n/** Returns true if `value` is an IntegerValue . */\nexport function isInteger(\n value?: api.Value | null\n): value is { integerValue: string | number } {\n return !!value && 'integerValue' in value;\n}\n\n/** Returns true if `value` is a DoubleValue. */\nexport function isDouble(\n value?: api.Value | null\n): value is { doubleValue: string | number } {\n return !!value && 'doubleValue' in value;\n}\n\n/** Returns true if `value` is either an IntegerValue or a DoubleValue. */\nexport function isNumber(value?: api.Value | null): boolean {\n return isInteger(value) || isDouble(value);\n}\n\n/** Returns true if `value` is an ArrayValue. */\nexport function isArray(\n value?: api.Value | null\n): value is { arrayValue: api.ArrayValue } {\n return !!value && 'arrayValue' in value;\n}\n\n/** Returns true if `value` is a ReferenceValue. */\nexport function isReferenceValue(\n value?: api.Value | null\n): value is { referenceValue: string } {\n return !!value && 'referenceValue' in value;\n}\n\n/** Returns true if `value` is a NullValue. */\nexport function isNullValue(\n value?: api.Value | null\n): value is { nullValue: 'NULL_VALUE' } {\n return !!value && 'nullValue' in value;\n}\n\n/** Returns true if `value` is NaN. */\nexport function isNanValue(\n value?: api.Value | null\n): value is { doubleValue: 'NaN' | number } {\n return !!value && 'doubleValue' in value && isNaN(Number(value.doubleValue));\n}\n\n/** Returns true if `value` is a MapValue. */\nexport function isMapValue(\n value?: api.Value | null\n): value is { mapValue: api.MapValue } {\n return !!value && 'mapValue' in value;\n}\n","/**\n * @license\n * Copyright 2018 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport * as api from '../protos/firestore_proto_api';\n\nimport { Timestamp } from '../api/timestamp';\nimport { debugAssert } from '../util/assert';\nimport { JsonProtoSerializer } from '../remote/serializer';\nimport {\n valueEquals,\n isArray,\n isInteger,\n isNumber,\n normalizeNumber\n} from './values';\nimport { serverTimestamp } from './server_timestamps';\nimport { arrayEquals } from '../util/misc';\n\n/** Represents a transform within a TransformMutation. */\nexport interface TransformOperation {\n /**\n * Computes the local transform result against the provided `previousValue`,\n * optionally using the provided localWriteTime.\n */\n applyToLocalView(\n previousValue: api.Value | null,\n localWriteTime: Timestamp\n ): api.Value;\n\n /**\n * Computes a final transform result after the transform has been acknowledged\n * by the server, potentially using the server-provided transformResult.\n */\n applyToRemoteDocument(\n previousValue: api.Value | null,\n transformResult: api.Value | null\n ): api.Value;\n\n /**\n * If this transform operation is not idempotent, returns the base value to\n * persist for this transform. If a base value is returned, the transform\n * operation is always applied to this base value, even if document has\n * already been updated.\n *\n * Base values provide consistent behavior for non-idempotent transforms and\n * allow us to return the same latency-compensated value even if the backend\n * has already applied the transform operation. The base value is null for\n * idempotent transforms, as they can be re-played even if the backend has\n * already applied them.\n *\n * @return a base value to store along with the mutation, or null for\n * idempotent transforms.\n */\n computeBaseValue(previousValue: api.Value | null): api.Value | null;\n\n isEqual(other: TransformOperation): boolean;\n}\n\n/** Transforms a value into a server-generated timestamp. */\nexport class ServerTimestampTransform implements TransformOperation {\n private constructor() {}\n static instance = new ServerTimestampTransform();\n\n applyToLocalView(\n previousValue: api.Value | null,\n localWriteTime: Timestamp\n ): api.Value {\n return serverTimestamp(localWriteTime!, previousValue);\n }\n\n applyToRemoteDocument(\n previousValue: api.Value | null,\n transformResult: api.Value | null\n ): api.Value {\n return transformResult!;\n }\n\n computeBaseValue(previousValue: api.Value | null): api.Value | null {\n return null; // Server timestamps are idempotent and don't require a base value.\n }\n\n isEqual(other: TransformOperation): boolean {\n return other instanceof ServerTimestampTransform;\n }\n}\n\n/** Transforms an array value via a union operation. */\nexport class ArrayUnionTransformOperation implements TransformOperation {\n constructor(readonly elements: api.Value[]) {}\n\n applyToLocalView(\n previousValue: api.Value | null,\n localWriteTime: Timestamp\n ): api.Value {\n return this.apply(previousValue);\n }\n\n applyToRemoteDocument(\n previousValue: api.Value | null,\n transformResult: api.Value | null\n ): api.Value {\n // The server just sends null as the transform result for array operations,\n // so we have to calculate a result the same as we do for local\n // applications.\n return this.apply(previousValue);\n }\n\n private apply(previousValue: api.Value | null): api.Value {\n const values = coercedFieldValuesArray(previousValue);\n for (const toUnion of this.elements) {\n if (!values.some(element => valueEquals(element, toUnion))) {\n values.push(toUnion);\n }\n }\n return { arrayValue: { values } };\n }\n\n computeBaseValue(previousValue: api.Value | null): api.Value | null {\n return null; // Array transforms are idempotent and don't require a base value.\n }\n\n isEqual(other: TransformOperation): boolean {\n return (\n other instanceof ArrayUnionTransformOperation &&\n arrayEquals(this.elements, other.elements, valueEquals)\n );\n }\n}\n\n/** Transforms an array value via a remove operation. */\nexport class ArrayRemoveTransformOperation implements TransformOperation {\n constructor(readonly elements: api.Value[]) {}\n\n applyToLocalView(\n previousValue: api.Value | null,\n localWriteTime: Timestamp\n ): api.Value {\n return this.apply(previousValue);\n }\n\n applyToRemoteDocument(\n previousValue: api.Value | null,\n transformResult: api.Value | null\n ): api.Value {\n // The server just sends null as the transform result for array operations,\n // so we have to calculate a result the same as we do for local\n // applications.\n return this.apply(previousValue);\n }\n\n private apply(previousValue: api.Value | null): api.Value {\n let values = coercedFieldValuesArray(previousValue);\n for (const toRemove of this.elements) {\n values = values.filter(element => !valueEquals(element, toRemove));\n }\n return { arrayValue: { values } };\n }\n\n computeBaseValue(previousValue: api.Value | null): api.Value | null {\n return null; // Array transforms are idempotent and don't require a base value.\n }\n\n isEqual(other: TransformOperation): boolean {\n return (\n other instanceof ArrayRemoveTransformOperation &&\n arrayEquals(this.elements, other.elements, valueEquals)\n );\n }\n}\n\n/**\n * Implements the backend semantics for locally computed NUMERIC_ADD (increment)\n * transforms. Converts all field values to integers or doubles, but unlike the\n * backend does not cap integer values at 2^63. Instead, JavaScript number\n * arithmetic is used and precision loss can occur for values greater than 2^53.\n */\nexport class NumericIncrementTransformOperation implements TransformOperation {\n constructor(\n private readonly serializer: JsonProtoSerializer,\n readonly operand: api.Value\n ) {\n debugAssert(\n isNumber(operand),\n 'NumericIncrementTransform transform requires a NumberValue'\n );\n }\n\n applyToLocalView(\n previousValue: api.Value | null,\n localWriteTime: Timestamp\n ): api.Value {\n // PORTING NOTE: Since JavaScript's integer arithmetic is limited to 53 bit\n // precision and resolves overflows by reducing precision, we do not\n // manually cap overflows at 2^63.\n const baseValue = this.computeBaseValue(previousValue);\n const sum = this.asNumber(baseValue) + this.asNumber(this.operand);\n if (isInteger(baseValue) && isInteger(this.operand)) {\n return this.serializer.toInteger(sum);\n } else {\n return this.serializer.toDouble(sum);\n }\n }\n\n applyToRemoteDocument(\n previousValue: api.Value | null,\n transformResult: api.Value | null\n ): api.Value {\n debugAssert(\n transformResult !== null,\n \"Didn't receive transformResult for NUMERIC_ADD transform\"\n );\n return transformResult;\n }\n\n /**\n * Inspects the provided value, returning the provided value if it is already\n * a NumberValue, otherwise returning a coerced value of 0.\n */\n computeBaseValue(previousValue: api.Value | null): api.Value {\n return isNumber(previousValue) ? previousValue! : { integerValue: 0 };\n }\n\n isEqual(other: TransformOperation): boolean {\n return (\n other instanceof NumericIncrementTransformOperation &&\n valueEquals(this.operand, other.operand)\n );\n }\n\n private asNumber(value: api.Value): number {\n return normalizeNumber(value.integerValue || value.doubleValue);\n }\n}\n\nfunction coercedFieldValuesArray(value: api.Value | null): api.Value[] {\n return isArray(value) && value.arrayValue.values\n ? value.arrayValue.values.slice()\n : [];\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport * as api from '../protos/firestore_proto_api';\n\nimport { Timestamp } from '../api/timestamp';\nimport { SnapshotVersion } from '../core/snapshot_version';\nimport { debugAssert, fail, hardAssert } from '../util/assert';\n\nimport {\n Document,\n MaybeDocument,\n NoDocument,\n UnknownDocument\n} from './document';\nimport { DocumentKey } from './document_key';\nimport { ObjectValue, ObjectValueBuilder } from './object_value';\nimport { FieldPath } from './path';\nimport { TransformOperation } from './transform_operation';\nimport { arrayEquals } from '../util/misc';\n\n/**\n * Provides a set of fields that can be used to partially patch a document.\n * FieldMask is used in conjunction with ObjectValue.\n * Examples:\n * foo - Overwrites foo entirely with the provided value. If foo is not\n * present in the companion ObjectValue, the field is deleted.\n * foo.bar - Overwrites only the field bar of the object foo.\n * If foo is not an object, foo is replaced with an object\n * containing foo\n */\nexport class FieldMask {\n constructor(readonly fields: FieldPath[]) {\n // TODO(dimond): validation of FieldMask\n // Sort the field mask to support `FieldMask.isEqual()` and assert below.\n fields.sort(FieldPath.comparator);\n debugAssert(\n !fields.some((v, i) => i !== 0 && v.isEqual(fields[i - 1])),\n 'FieldMask contains field that is not unique: ' +\n fields.find((v, i) => i !== 0 && v.isEqual(fields[i - 1]))!\n );\n }\n\n /**\n * Verifies that `fieldPath` is included by at least one field in this field\n * mask.\n *\n * This is an O(n) operation, where `n` is the size of the field mask.\n */\n covers(fieldPath: FieldPath): boolean {\n for (const fieldMaskPath of this.fields) {\n if (fieldMaskPath.isPrefixOf(fieldPath)) {\n return true;\n }\n }\n return false;\n }\n\n isEqual(other: FieldMask): boolean {\n return arrayEquals(this.fields, other.fields, (l, r) => l.isEqual(r));\n }\n}\n\n/** A field path and the TransformOperation to perform upon it. */\nexport class FieldTransform {\n constructor(\n readonly field: FieldPath,\n readonly transform: TransformOperation\n ) {}\n\n isEqual(other: FieldTransform): boolean {\n return (\n this.field.isEqual(other.field) && this.transform.isEqual(other.transform)\n );\n }\n}\n\n/** The result of successfully applying a mutation to the backend. */\nexport class MutationResult {\n constructor(\n /**\n * The version at which the mutation was committed:\n *\n * - For most operations, this is the updateTime in the WriteResult.\n * - For deletes, the commitTime of the WriteResponse (because deletes are\n * not stored and have no updateTime).\n *\n * Note that these versions can be different: No-op writes will not change\n * the updateTime even though the commitTime advances.\n */\n readonly version: SnapshotVersion,\n /**\n * The resulting fields returned from the backend after a\n * TransformMutation has been committed. Contains one FieldValue for each\n * FieldTransform that was in the mutation.\n *\n * Will be null if the mutation was not a TransformMutation.\n */\n readonly transformResults: Array | null\n ) {}\n}\n\nexport const enum MutationType {\n Set,\n Patch,\n Transform,\n Delete,\n Verify\n}\n\n/**\n * Encodes a precondition for a mutation. This follows the model that the\n * backend accepts with the special case of an explicit \"empty\" precondition\n * (meaning no precondition).\n */\nexport class Precondition {\n private constructor(\n readonly updateTime?: SnapshotVersion,\n readonly exists?: boolean\n ) {\n debugAssert(\n updateTime === undefined || exists === undefined,\n 'Precondition can specify \"exists\" or \"updateTime\" but not both'\n );\n }\n\n /** Creates a new empty Precondition. */\n static none(): Precondition {\n return new Precondition();\n }\n\n /** Creates a new Precondition with an exists flag. */\n static exists(exists: boolean): Precondition {\n return new Precondition(undefined, exists);\n }\n\n /** Creates a new Precondition based on a version a document exists at. */\n static updateTime(version: SnapshotVersion): Precondition {\n return new Precondition(version);\n }\n\n /** Returns whether this Precondition is empty. */\n get isNone(): boolean {\n return this.updateTime === undefined && this.exists === undefined;\n }\n\n /**\n * Returns true if the preconditions is valid for the given document\n * (or null if no document is available).\n */\n isValidFor(maybeDoc: MaybeDocument | null): boolean {\n if (this.updateTime !== undefined) {\n return (\n maybeDoc instanceof Document &&\n maybeDoc.version.isEqual(this.updateTime)\n );\n } else if (this.exists !== undefined) {\n return this.exists === maybeDoc instanceof Document;\n } else {\n debugAssert(this.isNone, 'Precondition should be empty');\n return true;\n }\n }\n\n isEqual(other: Precondition): boolean {\n return (\n this.exists === other.exists &&\n (this.updateTime\n ? !!other.updateTime && this.updateTime.isEqual(other.updateTime)\n : !other.updateTime)\n );\n }\n}\n\n/**\n * A mutation describes a self-contained change to a document. Mutations can\n * create, replace, delete, and update subsets of documents.\n *\n * Mutations not only act on the value of the document but also its version.\n *\n * For local mutations (mutations that haven't been committed yet), we preserve\n * the existing version for Set, Patch, and Transform mutations. For Delete\n * mutations, we reset the version to 0.\n *\n * Here's the expected transition table.\n *\n * MUTATION APPLIED TO RESULTS IN\n *\n * SetMutation Document(v3) Document(v3)\n * SetMutation NoDocument(v3) Document(v0)\n * SetMutation null Document(v0)\n * PatchMutation Document(v3) Document(v3)\n * PatchMutation NoDocument(v3) NoDocument(v3)\n * PatchMutation null null\n * TransformMutation Document(v3) Document(v3)\n * TransformMutation NoDocument(v3) NoDocument(v3)\n * TransformMutation null null\n * DeleteMutation Document(v3) NoDocument(v0)\n * DeleteMutation NoDocument(v3) NoDocument(v0)\n * DeleteMutation null NoDocument(v0)\n *\n * For acknowledged mutations, we use the updateTime of the WriteResponse as\n * the resulting version for Set, Patch, and Transform mutations. As deletes\n * have no explicit update time, we use the commitTime of the WriteResponse for\n * Delete mutations.\n *\n * If a mutation is acknowledged by the backend but fails the precondition check\n * locally, we return an `UnknownDocument` and rely on Watch to send us the\n * updated version.\n *\n * Note that TransformMutations don't create Documents (in the case of being\n * applied to a NoDocument), even though they would on the backend. This is\n * because the client always combines the TransformMutation with a SetMutation\n * or PatchMutation and we only want to apply the transform if the prior\n * mutation resulted in a Document (always true for a SetMutation, but not\n * necessarily for a PatchMutation).\n *\n * ## Subclassing Notes\n *\n * Subclasses of Mutation need to implement applyToRemoteDocument() and\n * applyToLocalView() to implement the actual behavior of applying the mutation\n * to some source document.\n */\nexport abstract class Mutation {\n abstract readonly type: MutationType;\n abstract readonly key: DocumentKey;\n abstract readonly precondition: Precondition;\n\n /**\n * Applies this mutation to the given MaybeDocument or null for the purposes\n * of computing a new remote document. If the input document doesn't match the\n * expected state (e.g. it is null or outdated), an `UnknownDocument` can be\n * returned.\n *\n * @param maybeDoc The document to mutate. The input document can be null if\n * the client has no knowledge of the pre-mutation state of the document.\n * @param mutationResult The result of applying the mutation from the backend.\n * @return The mutated document. The returned document may be an\n * UnknownDocument if the mutation could not be applied to the locally\n * cached base document.\n */\n abstract applyToRemoteDocument(\n maybeDoc: MaybeDocument | null,\n mutationResult: MutationResult\n ): MaybeDocument;\n\n /**\n * Applies this mutation to the given MaybeDocument or null for the purposes\n * of computing the new local view of a document. Both the input and returned\n * documents can be null.\n *\n * @param maybeDoc The document to mutate. The input document can be null if\n * the client has no knowledge of the pre-mutation state of the document.\n * @param baseDoc The state of the document prior to this mutation batch. The\n * input document can be null if the client has no knowledge of the\n * pre-mutation state of the document.\n * @param localWriteTime A timestamp indicating the local write time of the\n * batch this mutation is a part of.\n * @return The mutated document. The returned document may be null, but only\n * if maybeDoc was null and the mutation would not create a new document.\n */\n abstract applyToLocalView(\n maybeDoc: MaybeDocument | null,\n baseDoc: MaybeDocument | null,\n localWriteTime: Timestamp\n ): MaybeDocument | null;\n\n /**\n * If this mutation is not idempotent, returns the base value to persist with\n * this mutation. If a base value is returned, the mutation is always applied\n * to this base value, even if document has already been updated.\n *\n * The base value is a sparse object that consists of only the document\n * fields for which this mutation contains a non-idempotent transformation\n * (e.g. a numeric increment). The provided value guarantees consistent\n * behavior for non-idempotent transforms and allow us to return the same\n * latency-compensated value even if the backend has already applied the\n * mutation. The base value is null for idempotent mutations, as they can be\n * re-played even if the backend has already applied them.\n *\n * @return a base value to store along with the mutation, or null for\n * idempotent mutations.\n */\n abstract extractBaseValue(maybeDoc: MaybeDocument | null): ObjectValue | null;\n\n abstract isEqual(other: Mutation): boolean;\n\n protected verifyKeyMatches(maybeDoc: MaybeDocument | null): void {\n if (maybeDoc != null) {\n debugAssert(\n maybeDoc.key.isEqual(this.key),\n 'Can only apply a mutation to a document with the same key'\n );\n }\n }\n\n /**\n * Returns the version from the given document for use as the result of a\n * mutation. Mutations are defined to return the version of the base document\n * only if it is an existing document. Deleted and unknown documents have a\n * post-mutation version of SnapshotVersion.min().\n */\n protected static getPostMutationVersion(\n maybeDoc: MaybeDocument | null\n ): SnapshotVersion {\n if (maybeDoc instanceof Document) {\n return maybeDoc.version;\n } else {\n return SnapshotVersion.min();\n }\n }\n}\n\n/**\n * A mutation that creates or replaces the document at the given key with the\n * object value contents.\n */\nexport class SetMutation extends Mutation {\n constructor(\n readonly key: DocumentKey,\n readonly value: ObjectValue,\n readonly precondition: Precondition\n ) {\n super();\n }\n\n readonly type: MutationType = MutationType.Set;\n\n applyToRemoteDocument(\n maybeDoc: MaybeDocument | null,\n mutationResult: MutationResult\n ): MaybeDocument {\n this.verifyKeyMatches(maybeDoc);\n\n debugAssert(\n mutationResult.transformResults == null,\n 'Transform results received by SetMutation.'\n );\n\n // Unlike applyToLocalView, if we're applying a mutation to a remote\n // document the server has accepted the mutation so the precondition must\n // have held.\n\n const version = mutationResult.version;\n return new Document(this.key, version, this.value, {\n hasCommittedMutations: true\n });\n }\n\n applyToLocalView(\n maybeDoc: MaybeDocument | null,\n baseDoc: MaybeDocument | null,\n localWriteTime: Timestamp\n ): MaybeDocument | null {\n this.verifyKeyMatches(maybeDoc);\n\n if (!this.precondition.isValidFor(maybeDoc)) {\n return maybeDoc;\n }\n\n const version = Mutation.getPostMutationVersion(maybeDoc);\n return new Document(this.key, version, this.value, {\n hasLocalMutations: true\n });\n }\n\n extractBaseValue(maybeDoc: MaybeDocument | null): null {\n return null;\n }\n\n isEqual(other: Mutation): boolean {\n return (\n other instanceof SetMutation &&\n this.key.isEqual(other.key) &&\n this.value.isEqual(other.value) &&\n this.precondition.isEqual(other.precondition)\n );\n }\n}\n\n/**\n * A mutation that modifies fields of the document at the given key with the\n * given values. The values are applied through a field mask:\n *\n * * When a field is in both the mask and the values, the corresponding field\n * is updated.\n * * When a field is in neither the mask nor the values, the corresponding\n * field is unmodified.\n * * When a field is in the mask but not in the values, the corresponding field\n * is deleted.\n * * When a field is not in the mask but is in the values, the values map is\n * ignored.\n */\nexport class PatchMutation extends Mutation {\n constructor(\n readonly key: DocumentKey,\n readonly data: ObjectValue,\n readonly fieldMask: FieldMask,\n readonly precondition: Precondition\n ) {\n super();\n }\n\n readonly type: MutationType = MutationType.Patch;\n\n applyToRemoteDocument(\n maybeDoc: MaybeDocument | null,\n mutationResult: MutationResult\n ): MaybeDocument {\n this.verifyKeyMatches(maybeDoc);\n\n debugAssert(\n mutationResult.transformResults == null,\n 'Transform results received by PatchMutation.'\n );\n\n if (!this.precondition.isValidFor(maybeDoc)) {\n // Since the mutation was not rejected, we know that the precondition\n // matched on the backend. We therefore must not have the expected version\n // of the document in our cache and return an UnknownDocument with the\n // known updateTime.\n return new UnknownDocument(this.key, mutationResult.version);\n }\n\n const newData = this.patchDocument(maybeDoc);\n return new Document(this.key, mutationResult.version, newData, {\n hasCommittedMutations: true\n });\n }\n\n applyToLocalView(\n maybeDoc: MaybeDocument | null,\n baseDoc: MaybeDocument | null,\n localWriteTime: Timestamp\n ): MaybeDocument | null {\n this.verifyKeyMatches(maybeDoc);\n\n if (!this.precondition.isValidFor(maybeDoc)) {\n return maybeDoc;\n }\n\n const version = Mutation.getPostMutationVersion(maybeDoc);\n const newData = this.patchDocument(maybeDoc);\n return new Document(this.key, version, newData, {\n hasLocalMutations: true\n });\n }\n\n extractBaseValue(maybeDoc: MaybeDocument | null): null {\n return null;\n }\n\n isEqual(other: Mutation): boolean {\n return (\n other instanceof PatchMutation &&\n this.key.isEqual(other.key) &&\n this.fieldMask.isEqual(other.fieldMask) &&\n this.precondition.isEqual(other.precondition)\n );\n }\n\n /**\n * Patches the data of document if available or creates a new document. Note\n * that this does not check whether or not the precondition of this patch\n * holds.\n */\n private patchDocument(maybeDoc: MaybeDocument | null): ObjectValue {\n let data: ObjectValue;\n if (maybeDoc instanceof Document) {\n data = maybeDoc.data();\n } else {\n data = ObjectValue.empty();\n }\n return this.patchObject(data);\n }\n\n private patchObject(data: ObjectValue): ObjectValue {\n const builder = new ObjectValueBuilder(data);\n this.fieldMask.fields.forEach(fieldPath => {\n if (!fieldPath.isEmpty()) {\n const newValue = this.data.field(fieldPath);\n if (newValue !== null) {\n builder.set(fieldPath, newValue);\n } else {\n builder.delete(fieldPath);\n }\n }\n });\n return builder.build();\n }\n}\n\n/**\n * A mutation that modifies specific fields of the document with transform\n * operations. Currently the only supported transform is a server timestamp, but\n * IP Address, increment(n), etc. could be supported in the future.\n *\n * It is somewhat similar to a PatchMutation in that it patches specific fields\n * and has no effect when applied to a null or NoDocument (see comment on\n * Mutation for rationale).\n */\nexport class TransformMutation extends Mutation {\n readonly type: MutationType = MutationType.Transform;\n\n // NOTE: We set a precondition of exists: true as a safety-check, since we\n // always combine TransformMutations with a SetMutation or PatchMutation which\n // (if successful) should end up with an existing document.\n readonly precondition = Precondition.exists(true);\n\n constructor(\n readonly key: DocumentKey,\n readonly fieldTransforms: FieldTransform[]\n ) {\n super();\n }\n\n applyToRemoteDocument(\n maybeDoc: MaybeDocument | null,\n mutationResult: MutationResult\n ): MaybeDocument {\n this.verifyKeyMatches(maybeDoc);\n\n hardAssert(\n mutationResult.transformResults != null,\n 'Transform results missing for TransformMutation.'\n );\n\n if (!this.precondition.isValidFor(maybeDoc)) {\n // Since the mutation was not rejected, we know that the precondition\n // matched on the backend. We therefore must not have the expected version\n // of the document in our cache and return an UnknownDocument with the\n // known updateTime.\n return new UnknownDocument(this.key, mutationResult.version);\n }\n\n const doc = this.requireDocument(maybeDoc);\n const transformResults = this.serverTransformResults(\n maybeDoc,\n mutationResult.transformResults!\n );\n\n const version = mutationResult.version;\n const newData = this.transformObject(doc.data(), transformResults);\n return new Document(this.key, version, newData, {\n hasCommittedMutations: true\n });\n }\n\n applyToLocalView(\n maybeDoc: MaybeDocument | null,\n baseDoc: MaybeDocument | null,\n localWriteTime: Timestamp\n ): MaybeDocument | null {\n this.verifyKeyMatches(maybeDoc);\n\n if (!this.precondition.isValidFor(maybeDoc)) {\n return maybeDoc;\n }\n\n const doc = this.requireDocument(maybeDoc);\n const transformResults = this.localTransformResults(\n localWriteTime,\n maybeDoc,\n baseDoc\n );\n const newData = this.transformObject(doc.data(), transformResults);\n return new Document(this.key, doc.version, newData, {\n hasLocalMutations: true\n });\n }\n\n extractBaseValue(maybeDoc: MaybeDocument | null): ObjectValue | null {\n let baseObject: ObjectValueBuilder | null = null;\n for (const fieldTransform of this.fieldTransforms) {\n const existingValue =\n maybeDoc instanceof Document\n ? maybeDoc.field(fieldTransform.field)\n : undefined;\n const coercedValue = fieldTransform.transform.computeBaseValue(\n existingValue || null\n );\n\n if (coercedValue != null) {\n if (baseObject == null) {\n baseObject = new ObjectValueBuilder().set(\n fieldTransform.field,\n coercedValue\n );\n } else {\n baseObject = baseObject.set(fieldTransform.field, coercedValue);\n }\n }\n }\n return baseObject ? baseObject.build() : null;\n }\n\n isEqual(other: Mutation): boolean {\n return (\n other instanceof TransformMutation &&\n this.key.isEqual(other.key) &&\n arrayEquals(this.fieldTransforms, other.fieldTransforms, (l, r) =>\n l.isEqual(r)\n ) &&\n this.precondition.isEqual(other.precondition)\n );\n }\n\n /**\n * Asserts that the given MaybeDocument is actually a Document and verifies\n * that it matches the key for this mutation. Since we only support\n * transformations with precondition exists this method is guaranteed to be\n * safe.\n */\n private requireDocument(maybeDoc: MaybeDocument | null): Document {\n debugAssert(\n maybeDoc instanceof Document,\n 'Unknown MaybeDocument type ' + maybeDoc\n );\n debugAssert(\n maybeDoc.key.isEqual(this.key),\n 'Can only transform a document with the same key'\n );\n return maybeDoc;\n }\n\n /**\n * Creates a list of \"transform results\" (a transform result is a field value\n * representing the result of applying a transform) for use after a\n * TransformMutation has been acknowledged by the server.\n *\n * @param baseDoc The document prior to applying this mutation batch.\n * @param serverTransformResults The transform results received by the server.\n * @return The transform results list.\n */\n private serverTransformResults(\n baseDoc: MaybeDocument | null,\n serverTransformResults: Array\n ): api.Value[] {\n const transformResults: api.Value[] = [];\n hardAssert(\n this.fieldTransforms.length === serverTransformResults.length,\n `server transform result count (${serverTransformResults.length}) ` +\n `should match field transform count (${this.fieldTransforms.length})`\n );\n\n for (let i = 0; i < serverTransformResults.length; i++) {\n const fieldTransform = this.fieldTransforms[i];\n const transform = fieldTransform.transform;\n let previousValue: api.Value | null = null;\n if (baseDoc instanceof Document) {\n previousValue = baseDoc.field(fieldTransform.field);\n }\n transformResults.push(\n transform.applyToRemoteDocument(\n previousValue,\n serverTransformResults[i]\n )\n );\n }\n return transformResults;\n }\n\n /**\n * Creates a list of \"transform results\" (a transform result is a field value\n * representing the result of applying a transform) for use when applying a\n * TransformMutation locally.\n *\n * @param localWriteTime The local time of the transform mutation (used to\n * generate ServerTimestampValues).\n * @param maybeDoc The current state of the document after applying all\n * previous mutations.\n * @param baseDoc The document prior to applying this mutation batch.\n * @return The transform results list.\n */\n private localTransformResults(\n localWriteTime: Timestamp,\n maybeDoc: MaybeDocument | null,\n baseDoc: MaybeDocument | null\n ): api.Value[] {\n const transformResults: api.Value[] = [];\n for (const fieldTransform of this.fieldTransforms) {\n const transform = fieldTransform.transform;\n\n let previousValue: api.Value | null = null;\n if (maybeDoc instanceof Document) {\n previousValue = maybeDoc.field(fieldTransform.field);\n }\n\n if (previousValue === null && baseDoc instanceof Document) {\n // If the current document does not contain a value for the mutated\n // field, use the value that existed before applying this mutation\n // batch. This solves an edge case where a PatchMutation clears the\n // values in a nested map before the TransformMutation is applied.\n previousValue = baseDoc.field(fieldTransform.field);\n }\n\n transformResults.push(\n transform.applyToLocalView(previousValue, localWriteTime)\n );\n }\n return transformResults;\n }\n\n private transformObject(\n data: ObjectValue,\n transformResults: api.Value[]\n ): ObjectValue {\n debugAssert(\n transformResults.length === this.fieldTransforms.length,\n 'TransformResults length mismatch.'\n );\n\n const builder = new ObjectValueBuilder(data);\n for (let i = 0; i < this.fieldTransforms.length; i++) {\n const fieldTransform = this.fieldTransforms[i];\n const fieldPath = fieldTransform.field;\n builder.set(fieldPath, transformResults[i]);\n }\n return builder.build();\n }\n}\n\n/** A mutation that deletes the document at the given key. */\nexport class DeleteMutation extends Mutation {\n constructor(readonly key: DocumentKey, readonly precondition: Precondition) {\n super();\n }\n\n readonly type: MutationType = MutationType.Delete;\n\n applyToRemoteDocument(\n maybeDoc: MaybeDocument | null,\n mutationResult: MutationResult\n ): MaybeDocument {\n this.verifyKeyMatches(maybeDoc);\n\n debugAssert(\n mutationResult.transformResults == null,\n 'Transform results received by DeleteMutation.'\n );\n\n // Unlike applyToLocalView, if we're applying a mutation to a remote\n // document the server has accepted the mutation so the precondition must\n // have held.\n\n return new NoDocument(this.key, mutationResult.version, {\n hasCommittedMutations: true\n });\n }\n\n applyToLocalView(\n maybeDoc: MaybeDocument | null,\n baseDoc: MaybeDocument | null,\n localWriteTime: Timestamp\n ): MaybeDocument | null {\n this.verifyKeyMatches(maybeDoc);\n\n if (!this.precondition.isValidFor(maybeDoc)) {\n return maybeDoc;\n }\n\n if (maybeDoc) {\n debugAssert(\n maybeDoc.key.isEqual(this.key),\n 'Can only apply mutation to document with same key'\n );\n }\n return new NoDocument(this.key, SnapshotVersion.min());\n }\n\n extractBaseValue(maybeDoc: MaybeDocument | null): null {\n return null;\n }\n\n isEqual(other: Mutation): boolean {\n return (\n other instanceof DeleteMutation &&\n this.key.isEqual(other.key) &&\n this.precondition.isEqual(other.precondition)\n );\n }\n}\n\n/**\n * A mutation that verifies the existence of the document at the given key with\n * the provided precondition.\n *\n * The `verify` operation is only used in Transactions, and this class serves\n * primarily to facilitate serialization into protos.\n */\nexport class VerifyMutation extends Mutation {\n constructor(readonly key: DocumentKey, readonly precondition: Precondition) {\n super();\n }\n\n readonly type: MutationType = MutationType.Verify;\n\n applyToRemoteDocument(\n maybeDoc: MaybeDocument | null,\n mutationResult: MutationResult\n ): MaybeDocument {\n fail('VerifyMutation should only be used in Transactions.');\n }\n\n applyToLocalView(\n maybeDoc: MaybeDocument | null,\n baseDoc: MaybeDocument | null,\n localWriteTime: Timestamp\n ): MaybeDocument | null {\n fail('VerifyMutation should only be used in Transactions.');\n }\n\n extractBaseValue(maybeDoc: MaybeDocument | null): null {\n fail('VerifyMutation should only be used in Transactions.');\n }\n\n isEqual(other: Mutation): boolean {\n return (\n other instanceof VerifyMutation &&\n this.key.isEqual(other.key) &&\n this.precondition.isEqual(other.precondition)\n );\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport * as api from '../protos/firestore_proto_api';\n\nimport { debugAssert } from '../util/assert';\nimport { FieldMask } from './mutation';\nimport { FieldPath } from './path';\nimport { isServerTimestamp } from './server_timestamps';\nimport { valueEquals, isMapValue, typeOrder } from './values';\nimport { forEach } from '../util/obj';\n\nexport interface JsonObject {\n [name: string]: T;\n}\n\nexport const enum TypeOrder {\n // This order is based on the backend's ordering, but modified to support\n // server timestamps.\n NullValue = 0,\n BooleanValue = 1,\n NumberValue = 2,\n TimestampValue = 3,\n ServerTimestampValue = 4,\n StringValue = 5,\n BlobValue = 6,\n RefValue = 7,\n GeoPointValue = 8,\n ArrayValue = 9,\n ObjectValue = 10\n}\n\n/**\n * An ObjectValue represents a MapValue in the Firestore Proto and offers the\n * ability to add and remove fields (via the ObjectValueBuilder).\n */\nexport class ObjectValue {\n constructor(readonly proto: { mapValue: api.MapValue }) {\n debugAssert(\n !isServerTimestamp(proto),\n 'ServerTimestamps should be converted to ServerTimestampValue'\n );\n }\n\n static empty(): ObjectValue {\n return new ObjectValue({ mapValue: {} });\n }\n\n /**\n * Returns the value at the given path or null.\n *\n * @param path the path to search\n * @return The value at the path or if there it doesn't exist.\n */\n field(path: FieldPath): api.Value | null {\n if (path.isEmpty()) {\n return this.proto;\n } else {\n let value: api.Value = this.proto;\n for (let i = 0; i < path.length - 1; ++i) {\n if (!value.mapValue!.fields) {\n return null;\n }\n value = value.mapValue!.fields[path.get(i)];\n if (!isMapValue(value)) {\n return null;\n }\n }\n\n value = (value.mapValue!.fields || {})[path.lastSegment()];\n return value || null;\n }\n }\n\n isEqual(other: ObjectValue): boolean {\n return valueEquals(this.proto, other.proto);\n }\n}\n\n/**\n * An Overlay, which contains an update to apply. Can either be Value proto, a\n * map of Overlay values (to represent additional nesting at the given key) or\n * `null` (to represent field deletes).\n */\ntype Overlay = Map | api.Value | null;\n\n/**\n * An ObjectValueBuilder provides APIs to set and delete fields from an\n * ObjectValue.\n */\nexport class ObjectValueBuilder {\n /** A map that contains the accumulated changes in this builder. */\n private overlayMap = new Map();\n\n /**\n * @param baseObject The object to mutate.\n */\n constructor(private readonly baseObject: ObjectValue = ObjectValue.empty()) {}\n\n /**\n * Sets the field to the provided value.\n *\n * @param path The field path to set.\n * @param value The value to set.\n * @return The current Builder instance.\n */\n set(path: FieldPath, value: api.Value): ObjectValueBuilder {\n debugAssert(\n !path.isEmpty(),\n 'Cannot set field for empty path on ObjectValue'\n );\n this.setOverlay(path, value);\n return this;\n }\n\n /**\n * Removes the field at the specified path. If there is no field at the\n * specified path, nothing is changed.\n *\n * @param path The field path to remove.\n * @return The current Builder instance.\n */\n delete(path: FieldPath): ObjectValueBuilder {\n debugAssert(\n !path.isEmpty(),\n 'Cannot delete field for empty path on ObjectValue'\n );\n this.setOverlay(path, null);\n return this;\n }\n\n /**\n * Adds `value` to the overlay map at `path`. Creates nested map entries if\n * needed.\n */\n private setOverlay(path: FieldPath, value: api.Value | null): void {\n let currentLevel = this.overlayMap;\n\n for (let i = 0; i < path.length - 1; ++i) {\n const currentSegment = path.get(i);\n let currentValue = currentLevel.get(currentSegment);\n\n if (currentValue instanceof Map) {\n // Re-use a previously created map\n currentLevel = currentValue;\n } else if (\n currentValue &&\n typeOrder(currentValue) === TypeOrder.ObjectValue\n ) {\n // Convert the existing Protobuf MapValue into a map\n currentValue = new Map(\n Object.entries(currentValue.mapValue!.fields || {})\n );\n currentLevel.set(currentSegment, currentValue);\n currentLevel = currentValue;\n } else {\n // Create an empty map to represent the current nesting level\n currentValue = new Map();\n currentLevel.set(currentSegment, currentValue);\n currentLevel = currentValue;\n }\n }\n\n currentLevel.set(path.lastSegment(), value);\n }\n\n /** Returns an ObjectValue with all mutations applied. */\n build(): ObjectValue {\n const mergedResult = this.applyOverlay(\n FieldPath.EMPTY_PATH,\n this.overlayMap\n );\n if (mergedResult != null) {\n return new ObjectValue(mergedResult);\n } else {\n return this.baseObject;\n }\n }\n\n /**\n * Applies any overlays from `currentOverlays` that exist at `currentPath`\n * and returns the merged data at `currentPath` (or null if there were no\n * changes).\n *\n * @param currentPath The path at the current nesting level. Can be set to\n * FieldValue.EMPTY_PATH to represent the root.\n * @param currentOverlays The overlays at the current nesting level in the\n * same format as `overlayMap`.\n * @return The merged data at `currentPath` or null if no modifications\n * were applied.\n */\n private applyOverlay(\n currentPath: FieldPath,\n currentOverlays: Map\n ): { mapValue: api.MapValue } | null {\n let modified = false;\n\n const existingValue = this.baseObject.field(currentPath);\n const resultAtPath = isMapValue(existingValue)\n ? // If there is already data at the current path, base our\n // modifications on top of the existing data.\n { ...existingValue.mapValue.fields }\n : {};\n\n currentOverlays.forEach((value, pathSegment) => {\n if (value instanceof Map) {\n const nested = this.applyOverlay(currentPath.child(pathSegment), value);\n if (nested != null) {\n resultAtPath[pathSegment] = nested;\n modified = true;\n }\n } else if (value !== null) {\n resultAtPath[pathSegment] = value;\n modified = true;\n } else if (resultAtPath.hasOwnProperty(pathSegment)) {\n delete resultAtPath[pathSegment];\n modified = true;\n }\n });\n\n return modified ? { mapValue: { fields: resultAtPath } } : null;\n }\n}\n\n/**\n * Returns a FieldMask built from all fields in a MapValue.\n */\nexport function extractFieldMask(value: api.MapValue): FieldMask {\n const fields: FieldPath[] = [];\n forEach(value!.fields || {}, (key, value) => {\n const currentPath = new FieldPath([key]);\n if (isMapValue(value)) {\n const nestedMask = extractFieldMask(value.mapValue!);\n const nestedFields = nestedMask.fields;\n if (nestedFields.length === 0) {\n // Preserve the empty map by adding it to the FieldMask.\n fields.push(currentPath);\n } else {\n // For nested and non-empty ObjectValues, add the FieldPath of the\n // leaf nodes.\n for (const nestedPath of nestedFields) {\n fields.push(currentPath.child(nestedPath));\n }\n }\n } else {\n // For nested and non-empty ObjectValues, add the FieldPath of the leaf\n // nodes.\n fields.push(currentPath);\n }\n });\n return new FieldMask(fields);\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { fail } from '../util/assert';\nimport { Code } from '../util/error';\nimport { logError } from '../util/log';\n\n/**\n * Error Codes describing the different ways GRPC can fail. These are copied\n * directly from GRPC's sources here:\n *\n * https://github.com/grpc/grpc/blob/bceec94ea4fc5f0085d81235d8e1c06798dc341a/include/grpc%2B%2B/impl/codegen/status_code_enum.h\n *\n * Important! The names of these identifiers matter because the string forms\n * are used for reverse lookups from the webchannel stream. Do NOT change the\n * names of these identifiers or change this into a const enum.\n */\nenum RpcCode {\n OK = 0,\n CANCELLED = 1,\n UNKNOWN = 2,\n INVALID_ARGUMENT = 3,\n DEADLINE_EXCEEDED = 4,\n NOT_FOUND = 5,\n ALREADY_EXISTS = 6,\n PERMISSION_DENIED = 7,\n UNAUTHENTICATED = 16,\n RESOURCE_EXHAUSTED = 8,\n FAILED_PRECONDITION = 9,\n ABORTED = 10,\n OUT_OF_RANGE = 11,\n UNIMPLEMENTED = 12,\n INTERNAL = 13,\n UNAVAILABLE = 14,\n DATA_LOSS = 15\n}\n\n/**\n * Determines whether an error code represents a permanent error when received\n * in response to a non-write operation.\n *\n * See isPermanentWriteError for classifying write errors.\n */\nexport function isPermanentError(code: Code): boolean {\n switch (code) {\n case Code.OK:\n return fail('Treated status OK as error');\n case Code.CANCELLED:\n case Code.UNKNOWN:\n case Code.DEADLINE_EXCEEDED:\n case Code.RESOURCE_EXHAUSTED:\n case Code.INTERNAL:\n case Code.UNAVAILABLE:\n // Unauthenticated means something went wrong with our token and we need\n // to retry with new credentials which will happen automatically.\n case Code.UNAUTHENTICATED:\n return false;\n case Code.INVALID_ARGUMENT:\n case Code.NOT_FOUND:\n case Code.ALREADY_EXISTS:\n case Code.PERMISSION_DENIED:\n case Code.FAILED_PRECONDITION:\n // Aborted might be retried in some scenarios, but that is dependant on\n // the context and should handled individually by the calling code.\n // See https://cloud.google.com/apis/design/errors.\n case Code.ABORTED:\n case Code.OUT_OF_RANGE:\n case Code.UNIMPLEMENTED:\n case Code.DATA_LOSS:\n return true;\n default:\n return fail('Unknown status code: ' + code);\n }\n}\n\n/**\n * Determines whether an error code represents a permanent error when received\n * in response to a write operation.\n *\n * Write operations must be handled specially because as of b/119437764, ABORTED\n * errors on the write stream should be retried too (even though ABORTED errors\n * are not generally retryable).\n *\n * Note that during the initial handshake on the write stream an ABORTED error\n * signals that we should discard our stream token (i.e. it is permanent). This\n * means a handshake error should be classified with isPermanentError, above.\n */\nexport function isPermanentWriteError(code: Code): boolean {\n return isPermanentError(code) && code !== Code.ABORTED;\n}\n\n/**\n * Maps an error Code from a GRPC status identifier like 'NOT_FOUND'.\n *\n * @returns The Code equivalent to the given status string or undefined if\n * there is no match.\n */\nexport function mapCodeFromRpcStatus(status: string): Code | undefined {\n // lookup by string\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n const code: RpcCode = RpcCode[status as any] as any;\n if (code === undefined) {\n return undefined;\n }\n\n return mapCodeFromRpcCode(code);\n}\n\n/**\n * Maps an error Code from GRPC status code number, like 0, 1, or 14. These\n * are not the same as HTTP status codes.\n *\n * @returns The Code equivalent to the given GRPC status code. Fails if there\n * is no match.\n */\nexport function mapCodeFromRpcCode(code: number | undefined): Code {\n if (code === undefined) {\n // This shouldn't normally happen, but in certain error cases (like trying\n // to send invalid proto messages) we may get an error with no GRPC code.\n logError('GRPC error has no .code');\n return Code.UNKNOWN;\n }\n\n switch (code) {\n case RpcCode.OK:\n return Code.OK;\n case RpcCode.CANCELLED:\n return Code.CANCELLED;\n case RpcCode.UNKNOWN:\n return Code.UNKNOWN;\n case RpcCode.DEADLINE_EXCEEDED:\n return Code.DEADLINE_EXCEEDED;\n case RpcCode.RESOURCE_EXHAUSTED:\n return Code.RESOURCE_EXHAUSTED;\n case RpcCode.INTERNAL:\n return Code.INTERNAL;\n case RpcCode.UNAVAILABLE:\n return Code.UNAVAILABLE;\n case RpcCode.UNAUTHENTICATED:\n return Code.UNAUTHENTICATED;\n case RpcCode.INVALID_ARGUMENT:\n return Code.INVALID_ARGUMENT;\n case RpcCode.NOT_FOUND:\n return Code.NOT_FOUND;\n case RpcCode.ALREADY_EXISTS:\n return Code.ALREADY_EXISTS;\n case RpcCode.PERMISSION_DENIED:\n return Code.PERMISSION_DENIED;\n case RpcCode.FAILED_PRECONDITION:\n return Code.FAILED_PRECONDITION;\n case RpcCode.ABORTED:\n return Code.ABORTED;\n case RpcCode.OUT_OF_RANGE:\n return Code.OUT_OF_RANGE;\n case RpcCode.UNIMPLEMENTED:\n return Code.UNIMPLEMENTED;\n case RpcCode.DATA_LOSS:\n return Code.DATA_LOSS;\n default:\n return fail('Unknown status code: ' + code);\n }\n}\n\n/**\n * Maps an RPC code from a Code. This is the reverse operation from\n * mapCodeFromRpcCode and should really only be used in tests.\n */\nexport function mapRpcCodeFromCode(code: Code | undefined): number {\n if (code === undefined) {\n return RpcCode.OK;\n }\n\n switch (code) {\n case Code.OK:\n return RpcCode.OK;\n case Code.CANCELLED:\n return RpcCode.CANCELLED;\n case Code.UNKNOWN:\n return RpcCode.UNKNOWN;\n case Code.DEADLINE_EXCEEDED:\n return RpcCode.DEADLINE_EXCEEDED;\n case Code.RESOURCE_EXHAUSTED:\n return RpcCode.RESOURCE_EXHAUSTED;\n case Code.INTERNAL:\n return RpcCode.INTERNAL;\n case Code.UNAVAILABLE:\n return RpcCode.UNAVAILABLE;\n case Code.UNAUTHENTICATED:\n return RpcCode.UNAUTHENTICATED;\n case Code.INVALID_ARGUMENT:\n return RpcCode.INVALID_ARGUMENT;\n case Code.NOT_FOUND:\n return RpcCode.NOT_FOUND;\n case Code.ALREADY_EXISTS:\n return RpcCode.ALREADY_EXISTS;\n case Code.PERMISSION_DENIED:\n return RpcCode.PERMISSION_DENIED;\n case Code.FAILED_PRECONDITION:\n return RpcCode.FAILED_PRECONDITION;\n case Code.ABORTED:\n return RpcCode.ABORTED;\n case Code.OUT_OF_RANGE:\n return RpcCode.OUT_OF_RANGE;\n case Code.UNIMPLEMENTED:\n return RpcCode.UNIMPLEMENTED;\n case Code.DATA_LOSS:\n return RpcCode.DATA_LOSS;\n default:\n return fail('Unknown status code: ' + code);\n }\n}\n\n/**\n * Converts an HTTP Status Code to the equivalent error code.\n *\n * @param status An HTTP Status Code, like 200, 404, 503, etc.\n * @returns The equivalent Code. Unknown status codes are mapped to\n * Code.UNKNOWN.\n */\nexport function mapCodeFromHttpStatus(status: number): Code {\n // The canonical error codes for Google APIs [1] specify mapping onto HTTP\n // status codes but the mapping is not bijective. In each case of ambiguity\n // this function chooses a primary error.\n //\n // [1]\n // https://github.com/googleapis/googleapis/blob/master/google/rpc/code.proto\n switch (status) {\n case 200: // OK\n return Code.OK;\n\n case 400: // Bad Request\n return Code.INVALID_ARGUMENT;\n // Other possibilities based on the forward mapping\n // return Code.FAILED_PRECONDITION;\n // return Code.OUT_OF_RANGE;\n\n case 401: // Unauthorized\n return Code.UNAUTHENTICATED;\n\n case 403: // Forbidden\n return Code.PERMISSION_DENIED;\n\n case 404: // Not Found\n return Code.NOT_FOUND;\n\n case 409: // Conflict\n return Code.ABORTED;\n // Other possibilities:\n // return Code.ALREADY_EXISTS;\n\n case 416: // Range Not Satisfiable\n return Code.OUT_OF_RANGE;\n\n case 429: // Too Many Requests\n return Code.RESOURCE_EXHAUSTED;\n\n case 499: // Client Closed Request\n return Code.CANCELLED;\n\n case 500: // Internal Server Error\n return Code.UNKNOWN;\n // Other possibilities:\n // return Code.INTERNAL;\n // return Code.DATA_LOSS;\n\n case 501: // Unimplemented\n return Code.UNIMPLEMENTED;\n\n case 503: // Service Unavailable\n return Code.UNAVAILABLE;\n\n case 504: // Gateway Timeout\n return Code.DEADLINE_EXCEEDED;\n\n default:\n if (status >= 200 && status < 300) {\n return Code.OK;\n }\n if (status >= 400 && status < 500) {\n return Code.FAILED_PRECONDITION;\n }\n if (status >= 500 && status < 600) {\n return Code.INTERNAL;\n }\n return Code.UNKNOWN;\n }\n}\n\n/**\n * Converts an HTTP response's error status to the equivalent error code.\n *\n * @param status An HTTP error response status (\"FAILED_PRECONDITION\",\n * \"UNKNOWN\", etc.)\n * @returns The equivalent Code. Non-matching responses are mapped to\n * Code.UNKNOWN.\n */\nexport function mapCodeFromHttpResponseErrorStatus(status: string): Code {\n const serverError = status.toLowerCase().replace('_', '-');\n return Object.values(Code).indexOf(serverError as Code) >= 0\n ? (serverError as Code)\n : Code.UNKNOWN;\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport * as api from '../protos/firestore_proto_api';\n\nimport { SnapshotVersion } from '../core/snapshot_version';\nimport { fail } from '../util/assert';\n\nimport { DocumentKey } from './document_key';\nimport { ObjectValue } from './object_value';\nimport { FieldPath } from './path';\nimport { valueCompare } from './values';\n\nexport interface DocumentOptions {\n hasLocalMutations?: boolean;\n hasCommittedMutations?: boolean;\n}\n\n/**\n * The result of a lookup for a given path may be an existing document or a\n * marker that this document does not exist at a given version.\n */\nexport abstract class MaybeDocument {\n constructor(readonly key: DocumentKey, readonly version: SnapshotVersion) {}\n\n /**\n * Whether this document had a local mutation applied that has not yet been\n * acknowledged by Watch.\n */\n abstract get hasPendingWrites(): boolean;\n\n abstract isEqual(other: MaybeDocument | null | undefined): boolean;\n\n abstract toString(): string;\n}\n\n/**\n * Represents a document in Firestore with a key, version, data and whether the\n * data has local mutations applied to it.\n */\nexport class Document extends MaybeDocument {\n readonly hasLocalMutations: boolean;\n readonly hasCommittedMutations: boolean;\n\n constructor(\n key: DocumentKey,\n version: SnapshotVersion,\n private readonly objectValue: ObjectValue,\n options: DocumentOptions\n ) {\n super(key, version);\n this.hasLocalMutations = !!options.hasLocalMutations;\n this.hasCommittedMutations = !!options.hasCommittedMutations;\n }\n\n field(path: FieldPath): api.Value | null {\n return this.objectValue.field(path);\n }\n\n data(): ObjectValue {\n return this.objectValue;\n }\n\n toProto(): { mapValue: api.MapValue } {\n return this.objectValue.proto;\n }\n\n isEqual(other: MaybeDocument | null | undefined): boolean {\n return (\n other instanceof Document &&\n this.key.isEqual(other.key) &&\n this.version.isEqual(other.version) &&\n this.hasLocalMutations === other.hasLocalMutations &&\n this.hasCommittedMutations === other.hasCommittedMutations &&\n this.objectValue.isEqual(other.objectValue)\n );\n }\n\n toString(): string {\n return (\n `Document(${this.key}, ${\n this.version\n }, ${this.objectValue.toString()}, ` +\n `{hasLocalMutations: ${this.hasLocalMutations}}), ` +\n `{hasCommittedMutations: ${this.hasCommittedMutations}})`\n );\n }\n\n get hasPendingWrites(): boolean {\n return this.hasLocalMutations || this.hasCommittedMutations;\n }\n}\n\n/**\n * Compares the value for field `field` in the provided documents. Throws if\n * the field does not exist in both documents.\n */\nexport function compareDocumentsByField(\n field: FieldPath,\n d1: Document,\n d2: Document\n): number {\n const v1 = d1.field(field);\n const v2 = d2.field(field);\n if (v1 !== null && v2 !== null) {\n return valueCompare(v1, v2);\n } else {\n return fail(\"Trying to compare documents on fields that don't exist\");\n }\n}\n\n/**\n * A class representing a deleted document.\n * Version is set to 0 if we don't point to any specific time, otherwise it\n * denotes time we know it didn't exist at.\n */\nexport class NoDocument extends MaybeDocument {\n readonly hasCommittedMutations: boolean;\n\n constructor(\n key: DocumentKey,\n version: SnapshotVersion,\n options?: DocumentOptions\n ) {\n super(key, version);\n this.hasCommittedMutations = !!(options && options.hasCommittedMutations);\n }\n\n toString(): string {\n return `NoDocument(${this.key}, ${this.version})`;\n }\n\n get hasPendingWrites(): boolean {\n return this.hasCommittedMutations;\n }\n\n isEqual(other: MaybeDocument | null | undefined): boolean {\n return (\n other instanceof NoDocument &&\n other.hasCommittedMutations === this.hasCommittedMutations &&\n other.version.isEqual(this.version) &&\n other.key.isEqual(this.key)\n );\n }\n}\n\n/**\n * A class representing an existing document whose data is unknown (e.g. a\n * document that was updated without a known base document).\n */\nexport class UnknownDocument extends MaybeDocument {\n toString(): string {\n return `UnknownDocument(${this.key}, ${this.version})`;\n }\n\n get hasPendingWrites(): boolean {\n return true;\n }\n\n isEqual(other: MaybeDocument | null | undefined): boolean {\n return (\n other instanceof UnknownDocument &&\n other.version.isEqual(this.version) &&\n other.key.isEqual(this.key)\n );\n }\n}\n","/**\n * @license\n * Copyright 2019 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { DocumentKey } from '../model/document_key';\nimport { ResourcePath } from '../model/path';\nimport { isNullOrUndefined } from '../util/types';\nimport { Bound, Filter, OrderBy } from './query';\n\n/**\n * A Target represents the WatchTarget representation of a Query, which is used\n * by the LocalStore and the RemoteStore to keep track of and to execute\n * backend queries. While a Query can represent multiple Targets, each Targets\n * maps to a single WatchTarget in RemoteStore and a single TargetData entry\n * in persistence.\n */\nexport class Target {\n private memoizedCanonicalId: string | null = null;\n\n /**\n * Initializes a Target with a path and optional additional query constraints.\n * Path must currently be empty if this is a collection group query.\n *\n * NOTE: you should always construct `Target` from `Query.toTarget` instead of\n * using this constructor, because `Query` provides an implicit `orderBy`\n * property.\n */\n constructor(\n readonly path: ResourcePath,\n readonly collectionGroup: string | null = null,\n readonly orderBy: OrderBy[] = [],\n readonly filters: Filter[] = [],\n readonly limit: number | null = null,\n readonly startAt: Bound | null = null,\n readonly endAt: Bound | null = null\n ) {}\n\n canonicalId(): string {\n if (this.memoizedCanonicalId === null) {\n let canonicalId = this.path.canonicalString();\n if (this.collectionGroup !== null) {\n canonicalId += '|cg:' + this.collectionGroup;\n }\n canonicalId += '|f:';\n canonicalId += this.filters.map(f => f.canonicalId()).join(',');\n canonicalId += '|ob:';\n canonicalId += this.orderBy.map(o => o.canonicalId()).join(',');\n\n if (!isNullOrUndefined(this.limit)) {\n canonicalId += '|l:';\n canonicalId += this.limit!;\n }\n if (this.startAt) {\n canonicalId += '|lb:';\n canonicalId += this.startAt.canonicalId();\n }\n if (this.endAt) {\n canonicalId += '|ub:';\n canonicalId += this.endAt.canonicalId();\n }\n this.memoizedCanonicalId = canonicalId;\n }\n return this.memoizedCanonicalId;\n }\n\n toString(): string {\n let str = this.path.canonicalString();\n if (this.collectionGroup !== null) {\n str += ' collectionGroup=' + this.collectionGroup;\n }\n if (this.filters.length > 0) {\n str += `, filters: [${this.filters.join(', ')}]`;\n }\n if (!isNullOrUndefined(this.limit)) {\n str += ', limit: ' + this.limit;\n }\n if (this.orderBy.length > 0) {\n str += `, orderBy: [${this.orderBy.join(', ')}]`;\n }\n if (this.startAt) {\n str += ', startAt: ' + this.startAt.canonicalId();\n }\n if (this.endAt) {\n str += ', endAt: ' + this.endAt.canonicalId();\n }\n return `Target(${str})`;\n }\n\n isEqual(other: Target): boolean {\n if (this.limit !== other.limit) {\n return false;\n }\n\n if (this.orderBy.length !== other.orderBy.length) {\n return false;\n }\n\n for (let i = 0; i < this.orderBy.length; i++) {\n if (!this.orderBy[i].isEqual(other.orderBy[i])) {\n return false;\n }\n }\n\n if (this.filters.length !== other.filters.length) {\n return false;\n }\n\n for (let i = 0; i < this.filters.length; i++) {\n if (!this.filters[i].isEqual(other.filters[i])) {\n return false;\n }\n }\n\n if (this.collectionGroup !== other.collectionGroup) {\n return false;\n }\n\n if (!this.path.isEqual(other.path)) {\n return false;\n }\n\n if (\n this.startAt !== null\n ? !this.startAt.isEqual(other.startAt)\n : other.startAt !== null\n ) {\n return false;\n }\n\n return this.endAt !== null\n ? this.endAt.isEqual(other.endAt)\n : other.endAt === null;\n }\n\n isDocumentQuery(): boolean {\n return (\n DocumentKey.isDocumentKey(this.path) &&\n this.collectionGroup === null &&\n this.filters.length === 0\n );\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport * as api from '../protos/firestore_proto_api';\n\nimport { compareDocumentsByField, Document } from '../model/document';\nimport { DocumentKey } from '../model/document_key';\nimport {\n canonicalId,\n valueCompare,\n arrayValueContains,\n valueEquals,\n isArray,\n isNanValue,\n isNullValue,\n isReferenceValue,\n typeOrder\n} from '../model/values';\nimport { FieldPath, ResourcePath } from '../model/path';\nimport { debugAssert, fail } from '../util/assert';\nimport { Code, FirestoreError } from '../util/error';\nimport { isNullOrUndefined } from '../util/types';\nimport { Target } from './target';\n\nexport const enum LimitType {\n First = 'F',\n Last = 'L'\n}\n\n/**\n * Query encapsulates all the query attributes we support in the SDK. It can\n * be run against the LocalStore, as well as be converted to a `Target` to\n * query the RemoteStore results.\n */\nexport class Query {\n // TODO(firestorelite): Refactor this class so that methods that are not used\n // in the Lite client become tree-shakeable.\n\n static atPath(path: ResourcePath): Query {\n return new Query(path);\n }\n\n private memoizedOrderBy: OrderBy[] | null = null;\n\n // The corresponding `Target` of this `Query` instance.\n private memoizedTarget: Target | null = null;\n\n /**\n * Initializes a Query with a path and optional additional query constraints.\n * Path must currently be empty if this is a collection group query.\n */\n constructor(\n readonly path: ResourcePath,\n readonly collectionGroup: string | null = null,\n readonly explicitOrderBy: OrderBy[] = [],\n readonly filters: Filter[] = [],\n readonly limit: number | null = null,\n readonly limitType: LimitType = LimitType.First,\n readonly startAt: Bound | null = null,\n readonly endAt: Bound | null = null\n ) {\n if (this.startAt) {\n this.assertValidBound(this.startAt);\n }\n if (this.endAt) {\n this.assertValidBound(this.endAt);\n }\n }\n\n get orderBy(): OrderBy[] {\n if (this.memoizedOrderBy === null) {\n this.memoizedOrderBy = [];\n\n const inequalityField = this.getInequalityFilterField();\n const firstOrderByField = this.getFirstOrderByField();\n if (inequalityField !== null && firstOrderByField === null) {\n // In order to implicitly add key ordering, we must also add the\n // inequality filter field for it to be a valid query.\n // Note that the default inequality field and key ordering is ascending.\n if (!inequalityField.isKeyField()) {\n this.memoizedOrderBy.push(new OrderBy(inequalityField));\n }\n this.memoizedOrderBy.push(\n new OrderBy(FieldPath.keyField(), Direction.ASCENDING)\n );\n } else {\n debugAssert(\n inequalityField === null ||\n (firstOrderByField !== null &&\n inequalityField.isEqual(firstOrderByField)),\n 'First orderBy should match inequality field.'\n );\n let foundKeyOrdering = false;\n for (const orderBy of this.explicitOrderBy) {\n this.memoizedOrderBy.push(orderBy);\n if (orderBy.field.isKeyField()) {\n foundKeyOrdering = true;\n }\n }\n if (!foundKeyOrdering) {\n // The order of the implicit key ordering always matches the last\n // explicit order by\n const lastDirection =\n this.explicitOrderBy.length > 0\n ? this.explicitOrderBy[this.explicitOrderBy.length - 1].dir\n : Direction.ASCENDING;\n this.memoizedOrderBy.push(\n new OrderBy(FieldPath.keyField(), lastDirection)\n );\n }\n }\n }\n return this.memoizedOrderBy;\n }\n\n addFilter(filter: Filter): Query {\n debugAssert(\n this.getInequalityFilterField() == null ||\n !(filter instanceof FieldFilter) ||\n !filter.isInequality() ||\n filter.field.isEqual(this.getInequalityFilterField()!),\n 'Query must only have one inequality field.'\n );\n\n debugAssert(\n !this.isDocumentQuery(),\n 'No filtering allowed for document query'\n );\n\n const newFilters = this.filters.concat([filter]);\n return new Query(\n this.path,\n this.collectionGroup,\n this.explicitOrderBy.slice(),\n newFilters,\n this.limit,\n this.limitType,\n this.startAt,\n this.endAt\n );\n }\n\n addOrderBy(orderBy: OrderBy): Query {\n debugAssert(\n !this.startAt && !this.endAt,\n 'Bounds must be set after orderBy'\n );\n // TODO(dimond): validate that orderBy does not list the same key twice.\n const newOrderBy = this.explicitOrderBy.concat([orderBy]);\n return new Query(\n this.path,\n this.collectionGroup,\n newOrderBy,\n this.filters.slice(),\n this.limit,\n this.limitType,\n this.startAt,\n this.endAt\n );\n }\n\n withLimitToFirst(limit: number | null): Query {\n return new Query(\n this.path,\n this.collectionGroup,\n this.explicitOrderBy.slice(),\n this.filters.slice(),\n limit,\n LimitType.First,\n this.startAt,\n this.endAt\n );\n }\n\n withLimitToLast(limit: number | null): Query {\n return new Query(\n this.path,\n this.collectionGroup,\n this.explicitOrderBy.slice(),\n this.filters.slice(),\n limit,\n LimitType.Last,\n this.startAt,\n this.endAt\n );\n }\n\n withStartAt(bound: Bound): Query {\n return new Query(\n this.path,\n this.collectionGroup,\n this.explicitOrderBy.slice(),\n this.filters.slice(),\n this.limit,\n this.limitType,\n bound,\n this.endAt\n );\n }\n\n withEndAt(bound: Bound): Query {\n return new Query(\n this.path,\n this.collectionGroup,\n this.explicitOrderBy.slice(),\n this.filters.slice(),\n this.limit,\n this.limitType,\n this.startAt,\n bound\n );\n }\n\n /**\n * Helper to convert a collection group query into a collection query at a\n * specific path. This is used when executing collection group queries, since\n * we have to split the query into a set of collection queries at multiple\n * paths.\n */\n asCollectionQueryAtPath(path: ResourcePath): Query {\n return new Query(\n path,\n /*collectionGroup=*/ null,\n this.explicitOrderBy.slice(),\n this.filters.slice(),\n this.limit,\n this.limitType,\n this.startAt,\n this.endAt\n );\n }\n\n /**\n * Returns true if this query does not specify any query constraints that\n * could remove results.\n */\n matchesAllDocuments(): boolean {\n return (\n this.filters.length === 0 &&\n this.limit === null &&\n this.startAt == null &&\n this.endAt == null &&\n (this.explicitOrderBy.length === 0 ||\n (this.explicitOrderBy.length === 1 &&\n this.explicitOrderBy[0].field.isKeyField()))\n );\n }\n\n // TODO(b/29183165): This is used to get a unique string from a query to, for\n // example, use as a dictionary key, but the implementation is subject to\n // collisions. Make it collision-free.\n canonicalId(): string {\n return `${this.toTarget().canonicalId()}|lt:${this.limitType}`;\n }\n\n toString(): string {\n return `Query(target=${this.toTarget().toString()}; limitType=${\n this.limitType\n })`;\n }\n\n isEqual(other: Query): boolean {\n return (\n this.toTarget().isEqual(other.toTarget()) &&\n this.limitType === other.limitType\n );\n }\n\n docComparator(d1: Document, d2: Document): number {\n let comparedOnKeyField = false;\n for (const orderBy of this.orderBy) {\n const comp = orderBy.compare(d1, d2);\n if (comp !== 0) {\n return comp;\n }\n comparedOnKeyField = comparedOnKeyField || orderBy.field.isKeyField();\n }\n // Assert that we actually compared by key\n debugAssert(\n comparedOnKeyField,\n \"orderBy used that doesn't compare on key field\"\n );\n return 0;\n }\n\n matches(doc: Document): boolean {\n return (\n this.matchesPathAndCollectionGroup(doc) &&\n this.matchesOrderBy(doc) &&\n this.matchesFilters(doc) &&\n this.matchesBounds(doc)\n );\n }\n\n hasLimitToFirst(): boolean {\n return !isNullOrUndefined(this.limit) && this.limitType === LimitType.First;\n }\n\n hasLimitToLast(): boolean {\n return !isNullOrUndefined(this.limit) && this.limitType === LimitType.Last;\n }\n\n getFirstOrderByField(): FieldPath | null {\n return this.explicitOrderBy.length > 0\n ? this.explicitOrderBy[0].field\n : null;\n }\n\n getInequalityFilterField(): FieldPath | null {\n for (const filter of this.filters) {\n if (filter instanceof FieldFilter && filter.isInequality()) {\n return filter.field;\n }\n }\n return null;\n }\n\n // Checks if any of the provided Operators are included in the query and\n // returns the first one that is, or null if none are.\n findFilterOperator(operators: Operator[]): Operator | null {\n for (const filter of this.filters) {\n if (filter instanceof FieldFilter) {\n if (operators.indexOf(filter.op) >= 0) {\n return filter.op;\n }\n }\n }\n return null;\n }\n\n isDocumentQuery(): boolean {\n return this.toTarget().isDocumentQuery();\n }\n\n isCollectionGroupQuery(): boolean {\n return this.collectionGroup !== null;\n }\n\n /**\n * Converts this `Query` instance to it's corresponding `Target`\n * representation.\n */\n toTarget(): Target {\n if (!this.memoizedTarget) {\n if (this.limitType === LimitType.First) {\n this.memoizedTarget = new Target(\n this.path,\n this.collectionGroup,\n this.orderBy,\n this.filters,\n this.limit,\n this.startAt,\n this.endAt\n );\n } else {\n // Flip the orderBy directions since we want the last results\n const orderBys = [] as OrderBy[];\n for (const orderBy of this.orderBy) {\n const dir =\n orderBy.dir === Direction.DESCENDING\n ? Direction.ASCENDING\n : Direction.DESCENDING;\n orderBys.push(new OrderBy(orderBy.field, dir));\n }\n\n // We need to swap the cursors to match the now-flipped query ordering.\n const startAt = this.endAt\n ? new Bound(this.endAt.position, !this.endAt.before)\n : null;\n const endAt = this.startAt\n ? new Bound(this.startAt.position, !this.startAt.before)\n : null;\n\n // Now return as a LimitType.First query.\n this.memoizedTarget = new Target(\n this.path,\n this.collectionGroup,\n orderBys,\n this.filters,\n this.limit,\n startAt,\n endAt\n );\n }\n }\n return this.memoizedTarget!;\n }\n\n private matchesPathAndCollectionGroup(doc: Document): boolean {\n const docPath = doc.key.path;\n if (this.collectionGroup !== null) {\n // NOTE: this.path is currently always empty since we don't expose Collection\n // Group queries rooted at a document path yet.\n return (\n doc.key.hasCollectionId(this.collectionGroup) &&\n this.path.isPrefixOf(docPath)\n );\n } else if (DocumentKey.isDocumentKey(this.path)) {\n // exact match for document queries\n return this.path.isEqual(docPath);\n } else {\n // shallow ancestor queries by default\n return this.path.isImmediateParentOf(docPath);\n }\n }\n\n /**\n * A document must have a value for every ordering clause in order to show up\n * in the results.\n */\n private matchesOrderBy(doc: Document): boolean {\n for (const orderBy of this.explicitOrderBy) {\n // order by key always matches\n if (!orderBy.field.isKeyField() && doc.field(orderBy.field) === null) {\n return false;\n }\n }\n return true;\n }\n\n private matchesFilters(doc: Document): boolean {\n for (const filter of this.filters) {\n if (!filter.matches(doc)) {\n return false;\n }\n }\n return true;\n }\n\n /**\n * Makes sure a document is within the bounds, if provided.\n */\n private matchesBounds(doc: Document): boolean {\n if (this.startAt && !this.startAt.sortsBeforeDocument(this.orderBy, doc)) {\n return false;\n }\n if (this.endAt && this.endAt.sortsBeforeDocument(this.orderBy, doc)) {\n return false;\n }\n return true;\n }\n\n private assertValidBound(bound: Bound): void {\n debugAssert(\n bound.position.length <= this.orderBy.length,\n 'Bound is longer than orderBy'\n );\n }\n}\n\nexport abstract class Filter {\n abstract matches(doc: Document): boolean;\n abstract canonicalId(): string;\n abstract isEqual(filter: Filter): boolean;\n}\n\nexport const enum Operator {\n LESS_THAN = '<',\n LESS_THAN_OR_EQUAL = '<=',\n EQUAL = '==',\n GREATER_THAN = '>',\n GREATER_THAN_OR_EQUAL = '>=',\n ARRAY_CONTAINS = 'array-contains',\n IN = 'in',\n ARRAY_CONTAINS_ANY = 'array-contains-any'\n}\n\nexport class FieldFilter extends Filter {\n protected constructor(\n public field: FieldPath,\n public op: Operator,\n public value: api.Value\n ) {\n super();\n }\n\n /**\n * Creates a filter based on the provided arguments.\n */\n static create(field: FieldPath, op: Operator, value: api.Value): FieldFilter {\n if (field.isKeyField()) {\n if (op === Operator.IN) {\n debugAssert(\n isArray(value),\n 'Comparing on key with IN, but filter value not an ArrayValue'\n );\n debugAssert(\n (value.arrayValue.values || []).every(elem => isReferenceValue(elem)),\n 'Comparing on key with IN, but an array value was not a RefValue'\n );\n return new KeyFieldInFilter(field, value);\n } else {\n debugAssert(\n isReferenceValue(value),\n 'Comparing on key, but filter value not a RefValue'\n );\n debugAssert(\n op !== Operator.ARRAY_CONTAINS && op !== Operator.ARRAY_CONTAINS_ANY,\n `'${op.toString()}' queries don't make sense on document keys.`\n );\n return new KeyFieldFilter(field, op, value);\n }\n } else if (isNullValue(value)) {\n if (op !== Operator.EQUAL) {\n throw new FirestoreError(\n Code.INVALID_ARGUMENT,\n 'Invalid query. Null supports only equality comparisons.'\n );\n }\n return new FieldFilter(field, op, value);\n } else if (isNanValue(value)) {\n if (op !== Operator.EQUAL) {\n throw new FirestoreError(\n Code.INVALID_ARGUMENT,\n 'Invalid query. NaN supports only equality comparisons.'\n );\n }\n return new FieldFilter(field, op, value);\n } else if (op === Operator.ARRAY_CONTAINS) {\n return new ArrayContainsFilter(field, value);\n } else if (op === Operator.IN) {\n debugAssert(\n isArray(value),\n 'IN filter has invalid value: ' + value.toString()\n );\n return new InFilter(field, value);\n } else if (op === Operator.ARRAY_CONTAINS_ANY) {\n debugAssert(\n isArray(value),\n 'ARRAY_CONTAINS_ANY filter has invalid value: ' + value.toString()\n );\n return new ArrayContainsAnyFilter(field, value);\n } else {\n return new FieldFilter(field, op, value);\n }\n }\n\n matches(doc: Document): boolean {\n const other = doc.field(this.field);\n\n // Only compare types with matching backend order (such as double and int).\n return (\n other !== null &&\n typeOrder(this.value) === typeOrder(other) &&\n this.matchesComparison(valueCompare(other, this.value))\n );\n }\n\n protected matchesComparison(comparison: number): boolean {\n switch (this.op) {\n case Operator.LESS_THAN:\n return comparison < 0;\n case Operator.LESS_THAN_OR_EQUAL:\n return comparison <= 0;\n case Operator.EQUAL:\n return comparison === 0;\n case Operator.GREATER_THAN:\n return comparison > 0;\n case Operator.GREATER_THAN_OR_EQUAL:\n return comparison >= 0;\n default:\n return fail('Unknown FieldFilter operator: ' + this.op);\n }\n }\n\n isInequality(): boolean {\n return (\n [\n Operator.LESS_THAN,\n Operator.LESS_THAN_OR_EQUAL,\n Operator.GREATER_THAN,\n Operator.GREATER_THAN_OR_EQUAL\n ].indexOf(this.op) >= 0\n );\n }\n\n canonicalId(): string {\n // TODO(b/29183165): Technically, this won't be unique if two values have\n // the same description, such as the int 3 and the string \"3\". So we should\n // add the types in here somehow, too.\n return (\n this.field.canonicalString() +\n this.op.toString() +\n canonicalId(this.value)\n );\n }\n\n isEqual(other: Filter): boolean {\n if (other instanceof FieldFilter) {\n return (\n this.op === other.op &&\n this.field.isEqual(other.field) &&\n valueEquals(this.value, other.value)\n );\n } else {\n return false;\n }\n }\n\n toString(): string {\n return `${this.field.canonicalString()} ${this.op} ${canonicalId(\n this.value\n )}`;\n }\n}\n\n/** Filter that matches on key fields (i.e. '__name__'). */\nexport class KeyFieldFilter extends FieldFilter {\n private readonly key: DocumentKey;\n\n constructor(field: FieldPath, op: Operator, value: api.Value) {\n super(field, op, value);\n debugAssert(\n isReferenceValue(value),\n 'KeyFieldFilter expects a ReferenceValue'\n );\n this.key = DocumentKey.fromName(value.referenceValue);\n }\n\n matches(doc: Document): boolean {\n const comparison = DocumentKey.comparator(doc.key, this.key);\n return this.matchesComparison(comparison);\n }\n}\n\n/** Filter that matches on key fields within an array. */\nexport class KeyFieldInFilter extends FieldFilter {\n private readonly keys: DocumentKey[];\n\n constructor(field: FieldPath, value: api.Value) {\n super(field, Operator.IN, value);\n debugAssert(isArray(value), 'KeyFieldInFilter expects an ArrayValue');\n this.keys = (value.arrayValue.values || []).map(v => {\n debugAssert(\n isReferenceValue(v),\n 'Comparing on key with IN, but an array value was not a ReferenceValue'\n );\n return DocumentKey.fromName(v.referenceValue);\n });\n }\n\n matches(doc: Document): boolean {\n return this.keys.some(key => key.isEqual(doc.key));\n }\n}\n\n/** A Filter that implements the array-contains operator. */\nexport class ArrayContainsFilter extends FieldFilter {\n constructor(field: FieldPath, value: api.Value) {\n super(field, Operator.ARRAY_CONTAINS, value);\n }\n\n matches(doc: Document): boolean {\n const other = doc.field(this.field);\n return isArray(other) && arrayValueContains(other.arrayValue, this.value);\n }\n}\n\n/** A Filter that implements the IN operator. */\nexport class InFilter extends FieldFilter {\n constructor(field: FieldPath, value: api.Value) {\n super(field, Operator.IN, value);\n debugAssert(isArray(value), 'InFilter expects an ArrayValue');\n }\n\n matches(doc: Document): boolean {\n const other = doc.field(this.field);\n return other !== null && arrayValueContains(this.value.arrayValue!, other);\n }\n}\n\n/** A Filter that implements the array-contains-any operator. */\nexport class ArrayContainsAnyFilter extends FieldFilter {\n constructor(field: FieldPath, value: api.Value) {\n super(field, Operator.ARRAY_CONTAINS_ANY, value);\n debugAssert(isArray(value), 'ArrayContainsAnyFilter expects an ArrayValue');\n }\n\n matches(doc: Document): boolean {\n const other = doc.field(this.field);\n if (!isArray(other) || !other.arrayValue.values) {\n return false;\n }\n return other.arrayValue.values.some(val =>\n arrayValueContains(this.value.arrayValue!, val)\n );\n }\n}\n\n/**\n * The direction of sorting in an order by.\n */\nexport const enum Direction {\n ASCENDING = 'asc',\n DESCENDING = 'desc'\n}\n\n/**\n * Represents a bound of a query.\n *\n * The bound is specified with the given components representing a position and\n * whether it's just before or just after the position (relative to whatever the\n * query order is).\n *\n * The position represents a logical index position for a query. It's a prefix\n * of values for the (potentially implicit) order by clauses of a query.\n *\n * Bound provides a function to determine whether a document comes before or\n * after a bound. This is influenced by whether the position is just before or\n * just after the provided values.\n */\nexport class Bound {\n constructor(readonly position: api.Value[], readonly before: boolean) {}\n\n canonicalId(): string {\n // TODO(b/29183165): Make this collision robust.\n return `${this.before ? 'b' : 'a'}:${this.position\n .map(p => canonicalId(p))\n .join(',')}`;\n }\n\n /**\n * Returns true if a document sorts before a bound using the provided sort\n * order.\n */\n sortsBeforeDocument(orderBy: OrderBy[], doc: Document): boolean {\n debugAssert(\n this.position.length <= orderBy.length,\n \"Bound has more components than query's orderBy\"\n );\n let comparison = 0;\n for (let i = 0; i < this.position.length; i++) {\n const orderByComponent = orderBy[i];\n const component = this.position[i];\n if (orderByComponent.field.isKeyField()) {\n debugAssert(\n isReferenceValue(component),\n 'Bound has a non-key value where the key path is being used.'\n );\n comparison = DocumentKey.comparator(\n DocumentKey.fromName(component.referenceValue),\n doc.key\n );\n } else {\n const docValue = doc.field(orderByComponent.field);\n debugAssert(\n docValue !== null,\n 'Field should exist since document matched the orderBy already.'\n );\n comparison = valueCompare(component, docValue);\n }\n if (orderByComponent.dir === Direction.DESCENDING) {\n comparison = comparison * -1;\n }\n if (comparison !== 0) {\n break;\n }\n }\n return this.before ? comparison <= 0 : comparison < 0;\n }\n\n isEqual(other: Bound | null): boolean {\n if (other === null) {\n return false;\n }\n if (\n this.before !== other.before ||\n this.position.length !== other.position.length\n ) {\n return false;\n }\n for (let i = 0; i < this.position.length; i++) {\n const thisPosition = this.position[i];\n const otherPosition = other.position[i];\n if (!valueEquals(thisPosition, otherPosition)) {\n return false;\n }\n }\n return true;\n }\n}\n\n/**\n * An ordering on a field, in some Direction. Direction defaults to ASCENDING.\n */\nexport class OrderBy {\n readonly dir: Direction;\n private readonly isKeyOrderBy: boolean;\n\n constructor(readonly field: FieldPath, dir?: Direction) {\n if (dir === undefined) {\n dir = Direction.ASCENDING;\n }\n this.dir = dir;\n this.isKeyOrderBy = field.isKeyField();\n }\n\n compare(d1: Document, d2: Document): number {\n const comparison = this.isKeyOrderBy\n ? DocumentKey.comparator(d1.key, d2.key)\n : compareDocumentsByField(this.field, d1, d2);\n switch (this.dir) {\n case Direction.ASCENDING:\n return comparison;\n case Direction.DESCENDING:\n return -1 * comparison;\n default:\n return fail('Unknown direction: ' + this.dir);\n }\n }\n\n canonicalId(): string {\n // TODO(b/29183165): Make this collision robust.\n return this.field.canonicalString() + this.dir.toString();\n }\n\n toString(): string {\n return `${this.field.canonicalString()} (${this.dir})`;\n }\n\n isEqual(other: OrderBy): boolean {\n return this.dir === other.dir && this.field.isEqual(other.field);\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { SnapshotVersion } from '../core/snapshot_version';\nimport { Target } from '../core/target';\nimport { ListenSequenceNumber, TargetId } from '../core/types';\nimport { ByteString } from '../util/byte_string';\n\n/** An enumeration of the different purposes we have for targets. */\nexport const enum TargetPurpose {\n /** A regular, normal query target. */\n Listen,\n\n /**\n * The query target was used to refill a query after an existence filter mismatch.\n */\n ExistenceFilterMismatch,\n\n /** The query target was used to resolve a limbo document. */\n LimboResolution\n}\n\n/**\n * An immutable set of metadata that the local store tracks for each target.\n */\nexport class TargetData {\n constructor(\n /** The target being listened to. */\n readonly target: Target,\n /**\n * The target ID to which the target corresponds; Assigned by the\n * LocalStore for user listens and by the SyncEngine for limbo watches.\n */\n readonly targetId: TargetId,\n /** The purpose of the target. */\n readonly purpose: TargetPurpose,\n /**\n * The sequence number of the last transaction during which this target data\n * was modified.\n */\n readonly sequenceNumber: ListenSequenceNumber,\n /** The latest snapshot version seen for this target. */\n readonly snapshotVersion: SnapshotVersion = SnapshotVersion.min(),\n /**\n * The maximum snapshot version at which the associated view\n * contained no limbo documents.\n */\n readonly lastLimboFreeSnapshotVersion: SnapshotVersion = SnapshotVersion.min(),\n /**\n * An opaque, server-assigned token that allows watching a target to be\n * resumed after disconnecting without retransmitting all the data that\n * matches the target. The resume token essentially identifies a point in\n * time from which the server should resume sending results.\n */\n readonly resumeToken: ByteString = ByteString.EMPTY_BYTE_STRING\n ) {}\n\n /** Creates a new target data instance with an updated sequence number. */\n withSequenceNumber(sequenceNumber: number): TargetData {\n return new TargetData(\n this.target,\n this.targetId,\n this.purpose,\n sequenceNumber,\n this.snapshotVersion,\n this.lastLimboFreeSnapshotVersion,\n this.resumeToken\n );\n }\n\n /**\n * Creates a new target data instance with an updated resume token and\n * snapshot version.\n */\n withResumeToken(\n resumeToken: ByteString,\n snapshotVersion: SnapshotVersion\n ): TargetData {\n return new TargetData(\n this.target,\n this.targetId,\n this.purpose,\n this.sequenceNumber,\n snapshotVersion,\n this.lastLimboFreeSnapshotVersion,\n resumeToken\n );\n }\n\n /**\n * Creates a new target data instance with an updated last limbo free\n * snapshot version number.\n */\n withLastLimboFreeSnapshotVersion(\n lastLimboFreeSnapshotVersion: SnapshotVersion\n ): TargetData {\n return new TargetData(\n this.target,\n this.targetId,\n this.purpose,\n this.sequenceNumber,\n this.snapshotVersion,\n lastLimboFreeSnapshotVersion,\n this.resumeToken\n );\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nexport class ExistenceFilter {\n // TODO(b/33078163): just use simplest form of existence filter for now\n constructor(public count: number) {}\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { debugAssert, fail } from './assert';\n\n/*\n * Implementation of an immutable SortedMap using a Left-leaning\n * Red-Black Tree, adapted from the implementation in Mugs\n * (http://mads379.github.com/mugs/) by Mads Hartmann Jensen\n * (mads379@gmail.com).\n *\n * Original paper on Left-leaning Red-Black Trees:\n * http://www.cs.princeton.edu/~rs/talks/LLRB/LLRB.pdf\n *\n * Invariant 1: No red node has a red child\n * Invariant 2: Every leaf path has the same number of black nodes\n * Invariant 3: Only the left child can be red (left leaning)\n */\n\nexport type Comparator = (key1: K, key2: K) => number;\n\nexport interface Entry {\n key: K;\n value: V;\n}\n\n// An immutable sorted map implementation, based on a Left-leaning Red-Black\n// tree.\nexport class SortedMap {\n // visible for testing\n root: LLRBNode | LLRBEmptyNode;\n\n constructor(\n public comparator: Comparator,\n root?: LLRBNode | LLRBEmptyNode\n ) {\n this.root = root ? root : LLRBNode.EMPTY;\n }\n\n // Returns a copy of the map, with the specified key/value added or replaced.\n insert(key: K, value: V): SortedMap {\n return new SortedMap(\n this.comparator,\n this.root\n .insert(key, value, this.comparator)\n .copy(null, null, LLRBNode.BLACK, null, null)\n );\n }\n\n // Returns a copy of the map, with the specified key removed.\n remove(key: K): SortedMap {\n return new SortedMap(\n this.comparator,\n this.root\n .remove(key, this.comparator)\n .copy(null, null, LLRBNode.BLACK, null, null)\n );\n }\n\n // Returns the value of the node with the given key, or null.\n get(key: K): V | null {\n let node = this.root;\n while (!node.isEmpty()) {\n const cmp = this.comparator(key, node.key);\n if (cmp === 0) {\n return node.value;\n } else if (cmp < 0) {\n node = node.left;\n } else if (cmp > 0) {\n node = node.right;\n }\n }\n return null;\n }\n\n // Returns the index of the element in this sorted map, or -1 if it doesn't\n // exist.\n indexOf(key: K): number {\n // Number of nodes that were pruned when descending right\n let prunedNodes = 0;\n let node = this.root;\n while (!node.isEmpty()) {\n const cmp = this.comparator(key, node.key);\n if (cmp === 0) {\n return prunedNodes + node.left.size;\n } else if (cmp < 0) {\n node = node.left;\n } else {\n // Count all nodes left of the node plus the node itself\n prunedNodes += node.left.size + 1;\n node = node.right;\n }\n }\n // Node not found\n return -1;\n }\n\n isEmpty(): boolean {\n return this.root.isEmpty();\n }\n\n // Returns the total number of nodes in the map.\n get size(): number {\n return this.root.size;\n }\n\n // Returns the minimum key in the map.\n minKey(): K | null {\n return this.root.minKey();\n }\n\n // Returns the maximum key in the map.\n maxKey(): K | null {\n return this.root.maxKey();\n }\n\n // Traverses the map in key order and calls the specified action function\n // for each key/value pair. If action returns true, traversal is aborted.\n // Returns the first truthy value returned by action, or the last falsey\n // value returned by action.\n inorderTraversal(action: (k: K, v: V) => T): T {\n return (this.root as LLRBNode).inorderTraversal(action);\n }\n\n forEach(fn: (k: K, v: V) => void): void {\n this.inorderTraversal((k, v) => {\n fn(k, v);\n return false;\n });\n }\n\n toString(): string {\n const descriptions: string[] = [];\n this.inorderTraversal((k, v) => {\n descriptions.push(`${k}:${v}`);\n return false;\n });\n return `{${descriptions.join(', ')}}`;\n }\n\n // Traverses the map in reverse key order and calls the specified action\n // function for each key/value pair. If action returns true, traversal is\n // aborted.\n // Returns the first truthy value returned by action, or the last falsey\n // value returned by action.\n reverseTraversal(action: (k: K, v: V) => T): T {\n return (this.root as LLRBNode).reverseTraversal(action);\n }\n\n // Returns an iterator over the SortedMap.\n getIterator(): SortedMapIterator {\n return new SortedMapIterator(this.root, null, this.comparator, false);\n }\n\n getIteratorFrom(key: K): SortedMapIterator {\n return new SortedMapIterator(this.root, key, this.comparator, false);\n }\n\n getReverseIterator(): SortedMapIterator {\n return new SortedMapIterator(this.root, null, this.comparator, true);\n }\n\n getReverseIteratorFrom(key: K): SortedMapIterator {\n return new SortedMapIterator(this.root, key, this.comparator, true);\n }\n} // end SortedMap\n\n// An iterator over an LLRBNode.\nexport class SortedMapIterator {\n private isReverse: boolean;\n private nodeStack: Array | LLRBEmptyNode>;\n\n constructor(\n node: LLRBNode | LLRBEmptyNode,\n startKey: K | null,\n comparator: Comparator,\n isReverse: boolean\n ) {\n this.isReverse = isReverse;\n this.nodeStack = [];\n\n let cmp = 1;\n while (!node.isEmpty()) {\n cmp = startKey ? comparator(node.key, startKey) : 1;\n // flip the comparison if we're going in reverse\n if (isReverse) {\n cmp *= -1;\n }\n\n if (cmp < 0) {\n // This node is less than our start key. ignore it\n if (this.isReverse) {\n node = node.left;\n } else {\n node = node.right;\n }\n } else if (cmp === 0) {\n // This node is exactly equal to our start key. Push it on the stack,\n // but stop iterating;\n this.nodeStack.push(node);\n break;\n } else {\n // This node is greater than our start key, add it to the stack and move\n // to the next one\n this.nodeStack.push(node);\n if (this.isReverse) {\n node = node.right;\n } else {\n node = node.left;\n }\n }\n }\n }\n\n getNext(): Entry {\n debugAssert(\n this.nodeStack.length > 0,\n 'getNext() called on iterator when hasNext() is false.'\n );\n\n let node = this.nodeStack.pop()!;\n const result = { key: node.key, value: node.value };\n\n if (this.isReverse) {\n node = node.left;\n while (!node.isEmpty()) {\n this.nodeStack.push(node);\n node = node.right;\n }\n } else {\n node = node.right;\n while (!node.isEmpty()) {\n this.nodeStack.push(node);\n node = node.left;\n }\n }\n\n return result;\n }\n\n hasNext(): boolean {\n return this.nodeStack.length > 0;\n }\n\n peek(): Entry | null {\n if (this.nodeStack.length === 0) {\n return null;\n }\n\n const node = this.nodeStack[this.nodeStack.length - 1];\n return { key: node.key, value: node.value };\n }\n} // end SortedMapIterator\n\n// Represents a node in a Left-leaning Red-Black tree.\nexport class LLRBNode {\n readonly color: boolean;\n readonly left: LLRBNode | LLRBEmptyNode;\n readonly right: LLRBNode | LLRBEmptyNode;\n readonly size: number;\n\n // Empty node is shared between all LLRB trees.\n // eslint-disable-next-line @typescript-eslint/no-explicit-any\n static EMPTY: LLRBEmptyNode = null as any;\n\n static RED = true;\n static BLACK = false;\n\n constructor(\n public key: K,\n public value: V,\n color?: boolean,\n left?: LLRBNode | LLRBEmptyNode,\n right?: LLRBNode | LLRBEmptyNode\n ) {\n this.color = color != null ? color : LLRBNode.RED;\n this.left = left != null ? left : LLRBNode.EMPTY;\n this.right = right != null ? right : LLRBNode.EMPTY;\n this.size = this.left.size + 1 + this.right.size;\n }\n\n // Returns a copy of the current node, optionally replacing pieces of it.\n copy(\n key: K | null,\n value: V | null,\n color: boolean | null,\n left: LLRBNode | LLRBEmptyNode | null,\n right: LLRBNode | LLRBEmptyNode | null\n ): LLRBNode {\n return new LLRBNode(\n key != null ? key : this.key,\n value != null ? value : this.value,\n color != null ? color : this.color,\n left != null ? left : this.left,\n right != null ? right : this.right\n );\n }\n\n isEmpty(): boolean {\n return false;\n }\n\n // Traverses the tree in key order and calls the specified action function\n // for each node. If action returns true, traversal is aborted.\n // Returns the first truthy value returned by action, or the last falsey\n // value returned by action.\n inorderTraversal(action: (k: K, v: V) => T): T {\n return (\n (this.left as LLRBNode).inorderTraversal(action) ||\n action(this.key, this.value) ||\n (this.right as LLRBNode).inorderTraversal(action)\n );\n }\n\n // Traverses the tree in reverse key order and calls the specified action\n // function for each node. If action returns true, traversal is aborted.\n // Returns the first truthy value returned by action, or the last falsey\n // value returned by action.\n reverseTraversal(action: (k: K, v: V) => T): T {\n return (\n (this.right as LLRBNode).reverseTraversal(action) ||\n action(this.key, this.value) ||\n (this.left as LLRBNode).reverseTraversal(action)\n );\n }\n\n // Returns the minimum node in the tree.\n private min(): LLRBNode {\n if (this.left.isEmpty()) {\n return this;\n } else {\n return (this.left as LLRBNode).min();\n }\n }\n\n // Returns the maximum key in the tree.\n minKey(): K | null {\n return this.min().key;\n }\n\n // Returns the maximum key in the tree.\n maxKey(): K | null {\n if (this.right.isEmpty()) {\n return this.key;\n } else {\n return this.right.maxKey();\n }\n }\n\n // Returns new tree, with the key/value added.\n insert(key: K, value: V, comparator: Comparator): LLRBNode {\n let n: LLRBNode = this;\n const cmp = comparator(key, n.key);\n if (cmp < 0) {\n n = n.copy(null, null, null, n.left.insert(key, value, comparator), null);\n } else if (cmp === 0) {\n n = n.copy(null, value, null, null, null);\n } else {\n n = n.copy(\n null,\n null,\n null,\n null,\n n.right.insert(key, value, comparator)\n );\n }\n return n.fixUp();\n }\n\n private removeMin(): LLRBNode | LLRBEmptyNode {\n if (this.left.isEmpty()) {\n return LLRBNode.EMPTY;\n }\n let n: LLRBNode = this;\n if (!n.left.isRed() && !n.left.left.isRed()) {\n n = n.moveRedLeft();\n }\n n = n.copy(null, null, null, (n.left as LLRBNode).removeMin(), null);\n return n.fixUp();\n }\n\n // Returns new tree, with the specified item removed.\n remove(\n key: K,\n comparator: Comparator\n ): LLRBNode | LLRBEmptyNode {\n let smallest: LLRBNode;\n let n: LLRBNode = this;\n if (comparator(key, n.key) < 0) {\n if (!n.left.isEmpty() && !n.left.isRed() && !n.left.left.isRed()) {\n n = n.moveRedLeft();\n }\n n = n.copy(null, null, null, n.left.remove(key, comparator), null);\n } else {\n if (n.left.isRed()) {\n n = n.rotateRight();\n }\n if (!n.right.isEmpty() && !n.right.isRed() && !n.right.left.isRed()) {\n n = n.moveRedRight();\n }\n if (comparator(key, n.key) === 0) {\n if (n.right.isEmpty()) {\n return LLRBNode.EMPTY;\n } else {\n smallest = (n.right as LLRBNode).min();\n n = n.copy(\n smallest.key,\n smallest.value,\n null,\n null,\n (n.right as LLRBNode).removeMin()\n );\n }\n }\n n = n.copy(null, null, null, null, n.right.remove(key, comparator));\n }\n return n.fixUp();\n }\n\n isRed(): boolean {\n return this.color;\n }\n\n // Returns new tree after performing any needed rotations.\n private fixUp(): LLRBNode {\n let n: LLRBNode = this;\n if (n.right.isRed() && !n.left.isRed()) {\n n = n.rotateLeft();\n }\n if (n.left.isRed() && n.left.left.isRed()) {\n n = n.rotateRight();\n }\n if (n.left.isRed() && n.right.isRed()) {\n n = n.colorFlip();\n }\n return n;\n }\n\n private moveRedLeft(): LLRBNode {\n let n = this.colorFlip();\n if (n.right.left.isRed()) {\n n = n.copy(\n null,\n null,\n null,\n null,\n (n.right as LLRBNode).rotateRight()\n );\n n = n.rotateLeft();\n n = n.colorFlip();\n }\n return n;\n }\n\n private moveRedRight(): LLRBNode {\n let n = this.colorFlip();\n if (n.left.left.isRed()) {\n n = n.rotateRight();\n n = n.colorFlip();\n }\n return n;\n }\n\n private rotateLeft(): LLRBNode {\n const nl = this.copy(null, null, LLRBNode.RED, null, this.right.left);\n return (this.right as LLRBNode).copy(\n null,\n null,\n this.color,\n nl,\n null\n );\n }\n\n private rotateRight(): LLRBNode {\n const nr = this.copy(null, null, LLRBNode.RED, this.left.right, null);\n return (this.left as LLRBNode).copy(null, null, this.color, null, nr);\n }\n\n private colorFlip(): LLRBNode {\n const left = this.left.copy(null, null, !this.left.color, null, null);\n const right = this.right.copy(null, null, !this.right.color, null, null);\n return this.copy(null, null, !this.color, left, right);\n }\n\n // For testing.\n checkMaxDepth(): boolean {\n const blackDepth = this.check();\n if (Math.pow(2.0, blackDepth) <= this.size + 1) {\n return true;\n } else {\n return false;\n }\n }\n\n // In a balanced RB tree, the black-depth (number of black nodes) from root to\n // leaves is equal on both sides. This function verifies that or asserts.\n protected check(): number {\n if (this.isRed() && this.left.isRed()) {\n throw fail('Red node has red child(' + this.key + ',' + this.value + ')');\n }\n if (this.right.isRed()) {\n throw fail('Right child of (' + this.key + ',' + this.value + ') is red');\n }\n const blackDepth = (this.left as LLRBNode).check();\n if (blackDepth !== (this.right as LLRBNode).check()) {\n throw fail('Black depths differ');\n } else {\n return blackDepth + (this.isRed() ? 0 : 1);\n }\n }\n} // end LLRBNode\n\n// Represents an empty node (a leaf node in the Red-Black Tree).\nexport class LLRBEmptyNode {\n get key(): never {\n throw fail('LLRBEmptyNode has no key.');\n }\n get value(): never {\n throw fail('LLRBEmptyNode has no value.');\n }\n get color(): never {\n throw fail('LLRBEmptyNode has no color.');\n }\n get left(): never {\n throw fail('LLRBEmptyNode has no left child.');\n }\n get right(): never {\n throw fail('LLRBEmptyNode has no right child.');\n }\n size = 0;\n\n // Returns a copy of the current node.\n copy(\n key: K | null,\n value: V | null,\n color: boolean | null,\n left: LLRBNode | LLRBEmptyNode | null,\n right: LLRBNode | LLRBEmptyNode | null\n ): LLRBEmptyNode {\n return this;\n }\n\n // Returns a copy of the tree, with the specified key/value added.\n insert(key: K, value: V, comparator: Comparator): LLRBNode {\n return new LLRBNode(key, value);\n }\n\n // Returns a copy of the tree, with the specified key removed.\n remove(key: K, comparator: Comparator): LLRBEmptyNode {\n return this;\n }\n\n isEmpty(): boolean {\n return true;\n }\n\n inorderTraversal(action: (k: K, v: V) => boolean): boolean {\n return false;\n }\n\n reverseTraversal(action: (k: K, v: V) => boolean): boolean {\n return false;\n }\n\n minKey(): K | null {\n return null;\n }\n\n maxKey(): K | null {\n return null;\n }\n\n isRed(): boolean {\n return false;\n }\n\n // For testing.\n checkMaxDepth(): boolean {\n return true;\n }\n\n protected check(): 0 {\n return 0;\n }\n} // end LLRBEmptyNode\n\nLLRBNode.EMPTY = new LLRBEmptyNode();\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { SortedMap, SortedMapIterator } from './sorted_map';\n\n/**\n * SortedSet is an immutable (copy-on-write) collection that holds elements\n * in order specified by the provided comparator.\n *\n * NOTE: if provided comparator returns 0 for two elements, we consider them to\n * be equal!\n */\nexport class SortedSet {\n private data: SortedMap;\n\n constructor(private comparator: (left: T, right: T) => number) {\n this.data = new SortedMap(this.comparator);\n }\n\n has(elem: T): boolean {\n return this.data.get(elem) !== null;\n }\n\n first(): T | null {\n return this.data.minKey();\n }\n\n last(): T | null {\n return this.data.maxKey();\n }\n\n get size(): number {\n return this.data.size;\n }\n\n indexOf(elem: T): number {\n return this.data.indexOf(elem);\n }\n\n /** Iterates elements in order defined by \"comparator\" */\n forEach(cb: (elem: T) => void): void {\n this.data.inorderTraversal((k: T, v: boolean) => {\n cb(k);\n return false;\n });\n }\n\n /** Iterates over `elem`s such that: range[0] <= elem < range[1]. */\n forEachInRange(range: [T, T], cb: (elem: T) => void): void {\n const iter = this.data.getIteratorFrom(range[0]);\n while (iter.hasNext()) {\n const elem = iter.getNext();\n if (this.comparator(elem.key, range[1]) >= 0) {\n return;\n }\n cb(elem.key);\n }\n }\n\n /**\n * Iterates over `elem`s such that: start <= elem until false is returned.\n */\n forEachWhile(cb: (elem: T) => boolean, start?: T): void {\n let iter: SortedMapIterator;\n if (start !== undefined) {\n iter = this.data.getIteratorFrom(start);\n } else {\n iter = this.data.getIterator();\n }\n while (iter.hasNext()) {\n const elem = iter.getNext();\n const result = cb(elem.key);\n if (!result) {\n return;\n }\n }\n }\n\n /** Finds the least element greater than or equal to `elem`. */\n firstAfterOrEqual(elem: T): T | null {\n const iter = this.data.getIteratorFrom(elem);\n return iter.hasNext() ? iter.getNext().key : null;\n }\n\n getIterator(): SortedSetIterator {\n return new SortedSetIterator(this.data.getIterator());\n }\n\n getIteratorFrom(key: T): SortedSetIterator {\n return new SortedSetIterator(this.data.getIteratorFrom(key));\n }\n\n /** Inserts or updates an element */\n add(elem: T): SortedSet {\n return this.copy(this.data.remove(elem).insert(elem, true));\n }\n\n /** Deletes an element */\n delete(elem: T): SortedSet {\n if (!this.has(elem)) {\n return this;\n }\n return this.copy(this.data.remove(elem));\n }\n\n isEmpty(): boolean {\n return this.data.isEmpty();\n }\n\n unionWith(other: SortedSet): SortedSet {\n let result: SortedSet = this;\n\n // Make sure `result` always refers to the larger one of the two sets.\n if (result.size < other.size) {\n result = other;\n other = this;\n }\n\n other.forEach(elem => {\n result = result.add(elem);\n });\n return result;\n }\n\n isEqual(other: SortedSet): boolean {\n if (!(other instanceof SortedSet)) {\n return false;\n }\n if (this.size !== other.size) {\n return false;\n }\n\n const thisIt = this.data.getIterator();\n const otherIt = other.data.getIterator();\n while (thisIt.hasNext()) {\n const thisElem = thisIt.getNext().key;\n const otherElem = otherIt.getNext().key;\n if (this.comparator(thisElem, otherElem) !== 0) {\n return false;\n }\n }\n return true;\n }\n\n toArray(): T[] {\n const res: T[] = [];\n this.forEach(targetId => {\n res.push(targetId);\n });\n return res;\n }\n\n toString(): string {\n const result: T[] = [];\n this.forEach(elem => result.push(elem));\n return 'SortedSet(' + result.toString() + ')';\n }\n\n private copy(data: SortedMap): SortedSet {\n const result = new SortedSet(this.comparator);\n result.data = data;\n return result;\n }\n}\n\nexport class SortedSetIterator {\n constructor(private iter: SortedMapIterator) {}\n\n getNext(): T {\n return this.iter.getNext().key;\n }\n\n hasNext(): boolean {\n return this.iter.hasNext();\n }\n}\n","/**\n * @license\n * Copyright 2017 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { SnapshotVersion } from '../core/snapshot_version';\nimport { SortedMap } from '../util/sorted_map';\nimport { SortedSet } from '../util/sorted_set';\n\nimport { TargetId } from '../core/types';\nimport { primitiveComparator } from '../util/misc';\nimport { Document, MaybeDocument } from './document';\nimport { DocumentKey } from './document_key';\n\n/** Miscellaneous collection types / constants. */\nexport interface DocumentSizeEntry {\n maybeDocument: MaybeDocument;\n size: number;\n}\n\nexport type MaybeDocumentMap = SortedMap;\nconst EMPTY_MAYBE_DOCUMENT_MAP = new SortedMap(\n DocumentKey.comparator\n);\nexport function maybeDocumentMap(): MaybeDocumentMap {\n return EMPTY_MAYBE_DOCUMENT_MAP;\n}\n\nexport type NullableMaybeDocumentMap = SortedMap<\n DocumentKey,\n MaybeDocument | null\n>;\n\nexport function nullableMaybeDocumentMap(): NullableMaybeDocumentMap {\n return maybeDocumentMap();\n}\n\nexport interface DocumentSizeEntries {\n maybeDocuments: NullableMaybeDocumentMap;\n sizeMap: SortedMap;\n}\n\nexport type DocumentMap = SortedMap;\nconst EMPTY_DOCUMENT_MAP = new SortedMap(\n DocumentKey.comparator\n);\nexport function documentMap(): DocumentMap {\n return EMPTY_DOCUMENT_MAP;\n}\n\nexport type DocumentVersionMap = SortedMap;\nconst EMPTY_DOCUMENT_VERSION_MAP = new SortedMap(\n DocumentKey.comparator\n);\nexport function documentVersionMap(): DocumentVersionMap {\n return EMPTY_DOCUMENT_VERSION_MAP;\n}\n\nexport type DocumentKeySet = SortedSet;\nconst EMPTY_DOCUMENT_KEY_SET = new SortedSet(DocumentKey.comparator);\nexport function documentKeySet(...keys: DocumentKey[]): DocumentKeySet {\n let set = EMPTY_DOCUMENT_KEY_SET;\n for (const key of keys) {\n set = set.add(key);\n }\n return set;\n}\n\nexport type TargetIdSet = SortedSet;\nconst EMPTY_TARGET_ID_SET = new SortedSet