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  "readme": "# core-js\n\n[![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/zloirock/core-js?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge) [![version](https://img.shields.io/npm/v/core-js.svg)](https://www.npmjs.com/package/core-js) [![npm downloads](https://img.shields.io/npm/dm/core-js.svg)](http://npm-stat.com/charts.html?package=core-js&author=&from=2014-11-18) [![Build Status](https://travis-ci.org/zloirock/core-js.svg)](https://travis-ci.org/zloirock/core-js) [![devDependency status](https://david-dm.org/zloirock/core-js/dev-status.svg)](https://david-dm.org/zloirock/core-js?type=dev)\n#### As advertising: the author is looking for a good job :)\n\nModular standard library for JavaScript. Includes polyfills for [ECMAScript 5](#ecmascript-5), [ECMAScript 6](#ecmascript-6): [promises](#ecmascript-6-promise), [symbols](#ecmascript-6-symbol), [collections](#ecmascript-6-collections), iterators, [typed arrays](#ecmascript-6-typed-arrays), [ECMAScript 7+ proposals](#ecmascript-7-proposals), [setImmediate](#setimmediate), etc. Some additional features such as [dictionaries](#dict) or [extended partial application](#partial-application). You can require only needed features or use it without global namespace pollution.\n\n[*Example*](http://goo.gl/a2xexl):\n```js\nArray.from(new Set([1, 2, 3, 2, 1]));          // => [1, 2, 3]\n'*'.repeat(10);                                // => '**********'\nPromise.resolve(32).then(x => console.log(x)); // => 32\nsetImmediate(x => console.log(x), 42);         // => 42\n```\n\n[*Without global namespace pollution*](http://goo.gl/paOHb0):\n```js\nvar core = require('core-js/library'); // With a modular system, otherwise use global `core`\ncore.Array.from(new core.Set([1, 2, 3, 2, 1]));     // => [1, 2, 3]\ncore.String.repeat('*', 10);                        // => '**********'\ncore.Promise.resolve(32).then(x => console.log(x)); // => 32\ncore.setImmediate(x => console.log(x), 42);         // => 42\n```\n\n### Index\n- [Usage](#usage)\n  - [Basic](#basic)\n  - [CommonJS](#commonjs)\n  - [Custom build](#custom-build-from-the-command-line)\n- [Supported engines](#supported-engines)\n- [Features](#features)\n  - [ECMAScript 5](#ecmascript-5)\n  - [ECMAScript 6](#ecmascript-6)\n    - [ECMAScript 6: Object](#ecmascript-6-object)\n    - [ECMAScript 6: Function](#ecmascript-6-function)\n    - [ECMAScript 6: Array](#ecmascript-6-array)\n    - [ECMAScript 6: String](#ecmascript-6-string)\n    - [ECMAScript 6: RegExp](#ecmascript-6-regexp)\n    - [ECMAScript 6: Number](#ecmascript-6-number)\n    - [ECMAScript 6: Math](#ecmascript-6-math)\n    - [ECMAScript 6: Date](#ecmascript-6-date)\n    - [ECMAScript 6: Promise](#ecmascript-6-promise)\n    - [ECMAScript 6: Symbol](#ecmascript-6-symbol)\n    - [ECMAScript 6: Collections](#ecmascript-6-collections)\n    - [ECMAScript 6: Typed Arrays](#ecmascript-6-typed-arrays)\n    - [ECMAScript 6: Reflect](#ecmascript-6-reflect)\n  - [ECMAScript 7+ proposals](#ecmascript-7-proposals)\n    - [stage 4 proposals](#stage-4-proposals)\n    - [stage 3 proposals](#stage-3-proposals)\n    - [stage 2 proposals](#stage-2-proposals)\n    - [stage 1 proposals](#stage-1-proposals)\n    - [stage 0 proposals](#stage-0-proposals)\n    - [pre-stage 0 proposals](#pre-stage-0-proposals)\n  - [Web standards](#web-standards)\n    - [setTimeout / setInterval](#settimeout--setinterval)\n    - [setImmediate](#setimmediate)\n    - [iterable DOM collections](#iterable-dom-collections)\n  - [Non-standard](#non-standard)\n    - [Object](#object)\n    - [Dict](#dict)\n    - [partial application](#partial-application)\n    - [Number Iterator](#number-iterator)\n    - [escaping strings](#escaping-strings)\n    - [delay](#delay)\n    - [helpers for iterators](#helpers-for-iterators)\n- [Missing polyfills](#missing-polyfills)\n- [Changelog](./CHANGELOG.md)\n\n## Usage\n### Basic\n```\nnpm i core-js\nbower install core.js\n```\n\n```js\n// Default\nrequire('core-js');\n// Without global namespace pollution\nvar core = require('core-js/library');\n// Shim only\nrequire('core-js/shim');\n```\nIf you need complete build for browser, use builds from `core-js/client` path:  \n\n* [default](https://raw.githack.com/zloirock/core-js/v2.5.1/client/core.min.js): Includes all features, standard and non-standard.\n* [as a library](https://raw.githack.com/zloirock/core-js/v2.5.1/client/library.min.js): Like \"default\", but does not pollute the global namespace (see [2nd example at the top](#core-js)).\n* [shim only](https://raw.githack.com/zloirock/core-js/v2.5.1/client/shim.min.js): Only includes the standard methods.\n\nWarning: if you use `core-js` with the extension of native objects, require all needed `core-js` modules at the beginning of entry point of your application, otherwise, conflicts may occur.\n\n### CommonJS\nYou can require only needed modules.\n\n```js\nrequire('core-js/fn/set');\nrequire('core-js/fn/array/from');\nrequire('core-js/fn/array/find-index');\nArray.from(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]\n[1, 2, NaN, 3, 4].findIndex(isNaN);   // => 2\n\n// or, w/o global namespace pollution:\n\nvar Set       = require('core-js/library/fn/set');\nvar from      = require('core-js/library/fn/array/from');\nvar findIndex = require('core-js/library/fn/array/find-index');\nfrom(new Set([1, 2, 3, 2, 1]));      // => [1, 2, 3]\nfindIndex([1, 2, NaN, 3, 4], isNaN); // => 2\n```\nAvailable entry points for methods / constructors, as above examples, and namespaces: for example, `core-js/es6/array` (`core-js/library/es6/array`) contains all [ES6 `Array` features](#ecmascript-6-array), `core-js/es6` (`core-js/library/es6`) contains all ES6 features.\n\n##### Caveats when using CommonJS API:\n\n* `modules` path is internal API, does not inject all required dependencies and can be changed in minor or patch releases. Use it only for a custom build and / or if you know what are you doing.\n* `core-js` is extremely modular and uses a lot of very tiny modules, because of that for usage in browsers bundle up `core-js` instead of usage loader for each file, otherwise, you will have hundreds of requests.\n\n#### CommonJS and prototype methods without global namespace pollution\nIn the `library` version, we can't pollute prototypes of native constructors. Because of that, prototype methods transformed to static methods like in examples above. `babel` `runtime` transformer also can't transform them. But with transpilers we can use one more trick - [bind operator and virtual methods](https://github.com/zenparsing/es-function-bind). Special for that, available `/virtual/` entry points. Example:\n```js\nimport fill from 'core-js/library/fn/array/virtual/fill';\nimport findIndex from 'core-js/library/fn/array/virtual/find-index';\n\nArray(10)::fill(0).map((a, b) => b * b)::findIndex(it => it && !(it % 8)); // => 4\n\n// or\n\nimport {fill, findIndex} from 'core-js/library/fn/array/virtual';\n\nArray(10)::fill(0).map((a, b) => b * b)::findIndex(it => it && !(it % 8)); // => 4\n\n```\n\n### Custom build (from the command-line)\n```\nnpm i core-js && cd node_modules/core-js && npm i\nnpm run grunt build:core.dict,es6 -- --blacklist=es6.promise,es6.math --library=on --path=custom uglify\n```\nWhere `core.dict` and `es6` are modules (namespaces) names, which will be added to the build, `es6.promise` and `es6.math` are modules (namespaces) names, which will be excluded from the build, `--library=on` is flag for build without global namespace pollution and `custom` is target file name.\n\nAvailable namespaces: for example, `es6.array` contains [ES6 `Array` features](#ecmascript-6-array), `es6` contains all modules whose names start with `es6`.\n\n### Custom build (from external scripts)\n\n[`core-js-builder`](https://www.npmjs.com/package/core-js-builder) package exports a function that takes the same parameters as the `build` target from the previous section. This will conditionally include or exclude certain parts of `core-js`:\n\n```js\nrequire('core-js-builder')({\n  modules: ['es6', 'core.dict'], // modules / namespaces\n  blacklist: ['es6.reflect'],    // blacklist of modules / namespaces, by default - empty list\n  library: false,                // flag for build without global namespace pollution, by default - false\n  umd: true                      // use UMD wrapper for export `core` object, by default - true\n}).then(code => {\n  // ...\n}).catch(error => {\n  // ...\n});\n```\n## Supported engines\n**Tested in:**\n- Chrome 26+\n- Firefox 4+\n- Safari 5+\n- Opera 12+\n- Internet Explorer 6+ (sure, IE8- with ES3 limitations)\n- Edge\n- Android Browser 2.3+\n- iOS Safari 5.1+\n- PhantomJS 1.9 / 2.1\n- NodeJS 0.8+\n\n...and it doesn't mean `core-js` will not work in other engines, they just have not been tested.\n\n## Features:\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js(/library)       <- all features\ncore-js(/library)/shim  <- only polyfills\n```\n### ECMAScript 5\nAll features moved to the [`es6` namespace](#ecmascript-6), here just a list of features:\n```js\nObject\n  .create(proto | null, descriptors?)    -> object\n  .getPrototypeOf(object)                -> proto | null\n  .defineProperty(target, key, desc)     -> target, cap for ie8-\n  .defineProperties(target, descriptors) -> target, cap for ie8-\n  .getOwnPropertyDescriptor(object, key) -> desc\n  .getOwnPropertyNames(object)           -> array\n  .keys(object)                          -> array\n  .seal(object)                          -> object, cap for ie8-\n  .freeze(object)                        -> object, cap for ie8-\n  .preventExtensions(object)             -> object, cap for ie8-\n  .isSealed(object)                      -> bool, cap for ie8-\n  .isFrozen(object)                      -> bool, cap for ie8-\n  .isExtensible(object)                  -> bool, cap for ie8-\nArray\n  .isArray(var)                                -> bool\n  #slice(start?, end?)                         -> array, fix for ie7-\n  #join(string = ',')                          -> string, fix for ie7-\n  #indexOf(var, from?)                         -> int\n  #lastIndexOf(var, from?)                     -> int\n  #every(fn(val, index, @), that)              -> bool\n  #some(fn(val, index, @), that)               -> bool\n  #forEach(fn(val, index, @), that)            -> void\n  #map(fn(val, index, @), that)                -> array\n  #filter(fn(val, index, @), that)             -> array\n  #reduce(fn(memo, val, index, @), memo?)      -> var\n  #reduceRight(fn(memo, val, index, @), memo?) -> var\n  #sort(fn?)                                   -> @, fixes for some engines\nFunction\n  #bind(object, ...args) -> boundFn(...args)\nString\n  #split(separator, limit) -> array\n  #trim()                  -> str\nRegExp\n  #toString() -> str\nNumber\n  #toFixed(digits)        -> string\n  #toPrecision(precision) -> string\nparseInt(str, radix) -> int\nparseFloat(str)      -> num\nDate\n  .now()         -> int\n  #toISOString() -> string\n  #toJSON()      -> string\n```\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js(/library)/es5\n```\n\n### ECMAScript 6\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js(/library)/es6\n```\n#### ECMAScript 6: Object\nModules [`es6.object.assign`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.object.assign.js), [`es6.object.is`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.object.is.js), [`es6.object.set-prototype-of`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.object.set-prototype-of.js) and [`es6.object.to-string`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.object.to-string.js).\n\nIn ES6 most `Object` static methods should work with primitives. Modules [`es6.object.freeze`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.object.freeze.js), [`es6.object.seal`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.object.seal.js), [`es6.object.prevent-extensions`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.object.prevent-extensions.js), [`es6.object.is-frozen`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.object.is-frozen.js), [`es6.object.is-sealed`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.object.is-sealed.js), [`es6.object.is-extensible`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.object.is-extensible.js), [`es6.object.get-own-property-descriptor`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.object.get-own-property-descriptor.js), [`es6.object.get-prototype-of`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.object.get-prototype-of.js), [`es6.object.keys`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.object.keys.js) and [`es6.object.get-own-property-names`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.object.get-own-property-names.js).\n\nJust ES5 features: [`es6.object.create`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.object.create.js), [`es6.object.define-property`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.object.define-property.js) and [`es6.object.define-properties`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.object.es6.object.define-properties.js).\n```js\nObject\n  .assign(target, ...src)                -> target\n  .is(a, b)                              -> bool\n  .setPrototypeOf(target, proto | null)  -> target (required __proto__ - IE11+)\n  .create(object | null, descriptors?)   -> object\n  .getPrototypeOf(var)                   -> object | null\n  .defineProperty(object, key, desc)     -> target\n  .defineProperties(object, descriptors) -> target\n  .getOwnPropertyDescriptor(var, key)    -> desc | undefined\n  .keys(var)                             -> array\n  .getOwnPropertyNames(var)              -> array\n  .freeze(var)                           -> var\n  .seal(var)                             -> var\n  .preventExtensions(var)                -> var\n  .isFrozen(var)                         -> bool\n  .isSealed(var)                         -> bool\n  .isExtensible(var)                     -> bool\n  #toString()                            -> string, ES6 fix: @@toStringTag support\n```\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js(/library)/es6/object\ncore-js(/library)/fn/object/assign\ncore-js(/library)/fn/object/is\ncore-js(/library)/fn/object/set-prototype-of\ncore-js(/library)/fn/object/get-prototype-of\ncore-js(/library)/fn/object/create\ncore-js(/library)/fn/object/define-property\ncore-js(/library)/fn/object/define-properties\ncore-js(/library)/fn/object/get-own-property-descriptor\ncore-js(/library)/fn/object/keys\ncore-js(/library)/fn/object/get-own-property-names\ncore-js(/library)/fn/object/freeze\ncore-js(/library)/fn/object/seal\ncore-js(/library)/fn/object/prevent-extensions\ncore-js(/library)/fn/object/is-frozen\ncore-js(/library)/fn/object/is-sealed\ncore-js(/library)/fn/object/is-extensible\ncore-js/fn/object/to-string\n```\n[*Examples*](http://goo.gl/ywdwPz):\n```js\nvar foo = {q: 1, w: 2}\n  , bar = {e: 3, r: 4}\n  , baz = {t: 5, y: 6};\nObject.assign(foo, bar, baz); // => foo = {q: 1, w: 2, e: 3, r: 4, t: 5, y: 6}\n\nObject.is(NaN, NaN); // => true\nObject.is(0, -0);    // => false\nObject.is(42, 42);   // => true\nObject.is(42, '42'); // => false\n\nfunction Parent(){}\nfunction Child(){}\nObject.setPrototypeOf(Child.prototype, Parent.prototype);\nnew Child instanceof Child;  // => true\nnew Child instanceof Parent; // => true\n\nvar O = {};\nO[Symbol.toStringTag] = 'Foo';\n'' + O; // => '[object Foo]'\n\nObject.keys('qwe'); // => ['0', '1', '2']\nObject.getPrototypeOf('qwe') === String.prototype; // => true\n```\n#### ECMAScript 6: Function\nModules [`es6.function.name`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.function.name.js), [`es6.function.has-instance`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.function.has-instance.js). Just ES5: [`es6.function.bind`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.function.bind.js).\n```js\nFunction\n  #bind(object, ...args) -> boundFn(...args)\n  #name                  -> string (IE9+)\n  #@@hasInstance(var)    -> bool\n```\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js/es6/function\ncore-js/fn/function/name\ncore-js/fn/function/has-instance\ncore-js/fn/function/bind\ncore-js/fn/function/virtual/bind\n```\n[*Example*](http://goo.gl/zqu3Wp):\n```js\n(function foo(){}).name // => 'foo'\n\nconsole.log.bind(console, 42)(43); // => 42 43\n```\n#### ECMAScript 6: Array\nModules [`es6.array.from`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.from.js), [`es6.array.of`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.of.js), [`es6.array.copy-within`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.copy-within.js), [`es6.array.fill`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.fill.js), [`es6.array.find`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.find.js), [`es6.array.find-index`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.find-index.js), [`es6.array.iterator`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.iterator.js). ES5 features with fixes: [`es6.array.is-array`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.is-array.js), [`es6.array.slice`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.slice.js), [`es6.array.join`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.join.js), [`es6.array.index-of`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.index-of.js), [`es6.array.last-index-of`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.last-index-of.js), [`es6.array.every`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.every.js), [`es6.array.some`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.some.js), [`es6.array.for-each`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.for-each.js), [`es6.array.map`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.map.js), [`es6.array.filter`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.filter.js), [`es6.array.reduce`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.reduce.js), [`es6.array.reduce-right`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.reduce-right.js), [`es6.array.sort`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.array.sort.js).\n```js\nArray\n  .from(iterable | array-like, mapFn(val, index)?, that) -> array\n  .of(...args)                                           -> array\n  .isArray(var)                                          -> bool\n  #copyWithin(target = 0, start = 0, end = @length)      -> @\n  #fill(val, start = 0, end = @length)                   -> @\n  #find(fn(val, index, @), that)                         -> val\n  #findIndex(fn(val, index, @), that)                    -> index | -1\n  #values()                                              -> iterator\n  #keys()                                                -> iterator\n  #entries()                                             -> iterator\n  #join(string = ',')                                    -> string, fix for ie7-\n  #slice(start?, end?)                                   -> array, fix for ie7-\n  #indexOf(var, from?)                                   -> index | -1\n  #lastIndexOf(var, from?)                               -> index | -1\n  #every(fn(val, index, @), that)                        -> bool\n  #some(fn(val, index, @), that)                         -> bool\n  #forEach(fn(val, index, @), that)                      -> void\n  #map(fn(val, index, @), that)                          -> array\n  #filter(fn(val, index, @), that)                       -> array\n  #reduce(fn(memo, val, index, @), memo?)                -> var\n  #reduceRight(fn(memo, val, index, @), memo?)           -> var\n  #sort(fn?)                                             -> @, invalid arguments fix\n  #@@iterator()                                          -> iterator (values)\n  #@@unscopables                                         -> object (cap)\nArguments\n  #@@iterator() -> iterator (values, available only in core-js methods)\n```\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js(/library)/es6/array\ncore-js(/library)/fn/array/from\ncore-js(/library)/fn/array/of\ncore-js(/library)/fn/array/is-array\ncore-js(/library)/fn/array/iterator\ncore-js(/library)/fn/array/copy-within\ncore-js(/library)/fn/array/fill\ncore-js(/library)/fn/array/find\ncore-js(/library)/fn/array/find-index\ncore-js(/library)/fn/array/values\ncore-js(/library)/fn/array/keys\ncore-js(/library)/fn/array/entries\ncore-js(/library)/fn/array/slice\ncore-js(/library)/fn/array/join\ncore-js(/library)/fn/array/index-of\ncore-js(/library)/fn/array/last-index-of\ncore-js(/library)/fn/array/every\ncore-js(/library)/fn/array/some\ncore-js(/library)/fn/array/for-each\ncore-js(/library)/fn/array/map\ncore-js(/library)/fn/array/filter\ncore-js(/library)/fn/array/reduce\ncore-js(/library)/fn/array/reduce-right\ncore-js(/library)/fn/array/sort\ncore-js(/library)/fn/array/virtual/iterator\ncore-js(/library)/fn/array/virtual/copy-within\ncore-js(/library)/fn/array/virtual/fill\ncore-js(/library)/fn/array/virtual/find\ncore-js(/library)/fn/array/virtual/find-index\ncore-js(/library)/fn/array/virtual/values\ncore-js(/library)/fn/array/virtual/keys\ncore-js(/library)/fn/array/virtual/entries\ncore-js(/library)/fn/array/virtual/slice\ncore-js(/library)/fn/array/virtual/join\ncore-js(/library)/fn/array/virtual/index-of\ncore-js(/library)/fn/array/virtual/last-index-of\ncore-js(/library)/fn/array/virtual/every\ncore-js(/library)/fn/array/virtual/some\ncore-js(/library)/fn/array/virtual/for-each\ncore-js(/library)/fn/array/virtual/map\ncore-js(/library)/fn/array/virtual/filter\ncore-js(/library)/fn/array/virtual/reduce\ncore-js(/library)/fn/array/virtual/reduce-right\ncore-js(/library)/fn/array/virtual/sort\n```\n[*Examples*](http://goo.gl/oaUFUf):\n```js\nArray.from(new Set([1, 2, 3, 2, 1]));      // => [1, 2, 3]\nArray.from({0: 1, 1: 2, 2: 3, length: 3}); // => [1, 2, 3]\nArray.from('123', Number);                 // => [1, 2, 3]\nArray.from('123', function(it){\n  return it * it;\n});                                        // => [1, 4, 9]\n\nArray.of(1);       // => [1]\nArray.of(1, 2, 3); // => [1, 2, 3]\n\nvar array = ['a', 'b', 'c'];\n\nfor(var val of array)console.log(val);          // => 'a', 'b', 'c'\nfor(var val of array.values())console.log(val); // => 'a', 'b', 'c'\nfor(var key of array.keys())console.log(key);   // => 0, 1, 2\nfor(var [key, val] of array.entries()){\n  console.log(key);                             // => 0, 1, 2\n  console.log(val);                             // => 'a', 'b', 'c'\n}\n\nfunction isOdd(val){\n  return val % 2;\n}\n[4, 8, 15, 16, 23, 42].find(isOdd);      // => 15\n[4, 8, 15, 16, 23, 42].findIndex(isOdd); // => 2\n[4, 8, 15, 16, 23, 42].find(isNaN);      // => undefined\n[4, 8, 15, 16, 23, 42].findIndex(isNaN); // => -1\n\nArray(5).fill(42); // => [42, 42, 42, 42, 42]\n\n[1, 2, 3, 4, 5].copyWithin(0, 3); // => [4, 5, 3, 4, 5]\n```\n#### ECMAScript 6: String\nModules [`es6.string.from-code-point`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.from-code-point.js), [`es6.string.raw`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.raw.js), [`es6.string.iterator`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.iterator.js), [`es6.string.code-point-at`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.code-point-at.js), [`es6.string.ends-with`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.ends-with.js), [`es6.string.includes`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.includes.js), [`es6.string.repeat`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.repeat.js), [`es6.string.starts-with`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.starts-with.js) and [`es6.string.trim`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.trim.js).\n\nAnnex B HTML methods. Ugly, but it's also the part of the spec. Modules [`es6.string.anchor`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.anchor.js), [`es6.string.big`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.big.js), [`es6.string.blink`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.blink.js), [`es6.string.bold`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.bold.js), [`es6.string.fixed`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.fixed.js), [`es6.string.fontcolor`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.fontcolor.js), [`es6.string.fontsize`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.fontsize.js), [`es6.string.italics`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.italics.js), [`es6.string.link`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.link.js), [`es6.string.small`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.small.js), [`es6.string.strike`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.strike.js), [`es6.string.sub`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.sub.js) and [`es6.string.sup`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.string.sup.js).\n```js\nString\n  .fromCodePoint(...codePoints) -> str\n  .raw({raw}, ...substitutions) -> str\n  #includes(str, from?) -> bool\n  #startsWith(str, from?) -> bool\n  #endsWith(str, from?) -> bool\n  #repeat(num) -> str\n  #codePointAt(pos) -> uint\n  #trim() -> str, ES6 fix\n  #anchor(name)     -> str\n  #big()            -> str\n  #blink()          -> str\n  #bold()           -> str\n  #fixed()          -> str\n  #fontcolor(color) -> str\n  #fontsize(size)   -> str\n  #italics()        -> str\n  #link(url)        -> str\n  #small()          -> str\n  #strike()         -> str\n  #sub()            -> str\n  #sup()            -> str\n  #@@iterator() -> iterator (code points)\n```\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js(/library)/es6/string\ncore-js(/library)/fn/string/from-code-point\ncore-js(/library)/fn/string/raw\ncore-js(/library)/fn/string/includes\ncore-js(/library)/fn/string/starts-with\ncore-js(/library)/fn/string/ends-with\ncore-js(/library)/fn/string/repeat\ncore-js(/library)/fn/string/code-point-at\ncore-js(/library)/fn/string/trim\ncore-js(/library)/fn/string/anchor\ncore-js(/library)/fn/string/big\ncore-js(/library)/fn/string/blink\ncore-js(/library)/fn/string/bold\ncore-js(/library)/fn/string/fixed\ncore-js(/library)/fn/string/fontcolor\ncore-js(/library)/fn/string/fontsize\ncore-js(/library)/fn/string/italics\ncore-js(/library)/fn/string/link\ncore-js(/library)/fn/string/small\ncore-js(/library)/fn/string/strike\ncore-js(/library)/fn/string/sub\ncore-js(/library)/fn/string/sup\ncore-js(/library)/fn/string/iterator\ncore-js(/library)/fn/string/virtual/includes\ncore-js(/library)/fn/string/virtual/starts-with\ncore-js(/library)/fn/string/virtual/ends-with\ncore-js(/library)/fn/string/virtual/repeat\ncore-js(/library)/fn/string/virtual/code-point-at\ncore-js(/library)/fn/string/virtual/trim\ncore-js(/library)/fn/string/virtual/anchor\ncore-js(/library)/fn/string/virtual/big\ncore-js(/library)/fn/string/virtual/blink\ncore-js(/library)/fn/string/virtual/bold\ncore-js(/library)/fn/string/virtual/fixed\ncore-js(/library)/fn/string/virtual/fontcolor\ncore-js(/library)/fn/string/virtual/fontsize\ncore-js(/library)/fn/string/virtual/italics\ncore-js(/library)/fn/string/virtual/link\ncore-js(/library)/fn/string/virtual/small\ncore-js(/library)/fn/string/virtual/strike\ncore-js(/library)/fn/string/virtual/sub\ncore-js(/library)/fn/string/virtual/sup\ncore-js(/library)/fn/string/virtual/iterator\n```\n[*Examples*](http://goo.gl/3UaQ93):\n```js\nfor(var val of 'a𠮷b'){\n  console.log(val); // => 'a', '𠮷', 'b'\n}\n\n'foobarbaz'.includes('bar');      // => true\n'foobarbaz'.includes('bar', 4);   // => false\n'foobarbaz'.startsWith('foo');    // => true\n'foobarbaz'.startsWith('bar', 3); // => true\n'foobarbaz'.endsWith('baz');      // => true\n'foobarbaz'.endsWith('bar', 6);   // => true\n\n'string'.repeat(3); // => 'stringstringstring'\n\n'𠮷'.codePointAt(0); // => 134071\nString.fromCodePoint(97, 134071, 98); // => 'a𠮷b'\n\nvar name = 'Bob';\nString.raw`Hi\\n${name}!`;           // => 'Hi\\\\nBob!' (ES6 template string syntax)\nString.raw({raw: 'test'}, 0, 1, 2); // => 't0e1s2t'\n\n'foo'.bold();                     // => '<b>foo</b>'\n'bar'.anchor('a\"b');              // => '<a name=\"a&quot;b\">bar</a>'\n'baz'.link('http://example.com'); // => '<a href=\"http://example.com\">baz</a>'\n```\n#### ECMAScript 6: RegExp\nModules [`es6.regexp.constructor`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.regexp.constructor.js) and [`es6.regexp.flags`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.regexp.flags.js).\n\nSupport well-known [symbols](#ecmascript-6-symbol) `@@match`, `@@replace`, `@@search` and `@@split`, modules [`es6.regexp.match`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.regexp.match.js), [`es6.regexp.replace`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.regexp.replace.js), [`es6.regexp.search`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.regexp.search.js) and [`es6.regexp.split`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.regexp.split.js).\n```\n[new] RegExp(pattern, flags?) -> regexp, ES6 fix: can alter flags (IE9+)\n  #flags -> str (IE9+)\n  #toString() -> str, ES6 fixes\n  #@@match(str)             -> array | null\n  #@@replace(str, replacer) -> string\n  #@@search(str)            -> index\n  #@@split(str, limit)      -> array\nString\n  #match(tpl)             -> var, ES6 fix for support @@match\n  #replace(tpl, replacer) -> var, ES6 fix for support @@replace\n  #search(tpl)            -> var, ES6 fix for support @@search\n  #split(tpl, limit)      -> var, ES6 fix for support @@split, some fixes for old engines\n```\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js/es6/regexp\ncore-js/fn/regexp/constructor\ncore-js(/library)/fn/regexp/flags\ncore-js/fn/regexp/to-string\ncore-js/fn/regexp/match\ncore-js/fn/regexp/replace\ncore-js/fn/regexp/search\ncore-js/fn/regexp/split\n```\n[*Examples*](http://goo.gl/PiJxBD):\n```js\nRegExp(/./g, 'm'); // => /./m\n\n/foo/.flags;    // => ''\n/foo/gim.flags; // => 'gim'\n\n'foo'.match({[Symbol.match]: _ => 1});     // => 1\n'foo'.replace({[Symbol.replace]: _ => 2}); // => 2\n'foo'.search({[Symbol.search]: _ => 3});   // => 3\n'foo'.split({[Symbol.split]: _ => 4});     // => 4\n\nRegExp.prototype.toString.call({source: 'foo', flags: 'bar'}); // => '/foo/bar'\n```\n#### ECMAScript 6: Number\nModule [`es6.number.constructor`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.number.constructor.js). `Number` constructor support binary and octal literals, [*example*](http://goo.gl/jRd6b3):\n```js\nNumber('0b1010101'); // => 85\nNumber('0o7654321'); // => 2054353\n```\nModules [`es6.number.epsilon`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.number.epsilon.js), [`es6.number.is-finite`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.number.is-finite.js), [`es6.number.is-integer`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.number.is-integer.js), [`es6.number.is-nan`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.number.is-nan.js), [`es6.number.is-safe-integer`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.number.is-safe-integer.js), [`es6.number.max-safe-integer`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.number.max-safe-integer.js), [`es6.number.min-safe-integer`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.number.min-safe-integer.js), [`es6.number.parse-float`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.number.parse-float.js), [`es6.number.parse-int`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.number.parse-int.js), [`es6.number.to-fixed`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.number.to-fixed.js), [`es6.number.to-precision`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.number.to-precision.js), [`es6.parse-int`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.parse-int.js), [`es6.parse-float`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.parse-float.js).\n```js\n[new] Number(var)         -> number | number object\n  .isFinite(num)          -> bool\n  .isNaN(num)             -> bool\n  .isInteger(num)         -> bool\n  .isSafeInteger(num)     -> bool\n  .parseFloat(str)        -> num\n  .parseInt(str)          -> int\n  .EPSILON                -> num\n  .MAX_SAFE_INTEGER       -> int\n  .MIN_SAFE_INTEGER       -> int\n  #toFixed(digits)        -> string, fixes\n  #toPrecision(precision) -> string, fixes\nparseFloat(str)           -> num, fixes\nparseInt(str)             -> int, fixes\n```\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js(/library)/es6/number\ncore-js/es6/number/constructor\ncore-js(/library)/fn/number/is-finite\ncore-js(/library)/fn/number/is-nan\ncore-js(/library)/fn/number/is-integer\ncore-js(/library)/fn/number/is-safe-integer\ncore-js(/library)/fn/number/parse-float\ncore-js(/library)/fn/number/parse-int\ncore-js(/library)/fn/number/epsilon\ncore-js(/library)/fn/number/max-safe-integer\ncore-js(/library)/fn/number/min-safe-integer\ncore-js(/library)/fn/number/to-fixed\ncore-js(/library)/fn/number/to-precision\ncore-js(/library)/fn/parse-float\ncore-js(/library)/fn/parse-int\n```\n#### ECMAScript 6: Math\nModules [`es6.math.acosh`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.math.acosh.js), [`es6.math.asinh`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.math.asinh.js), [`es6.math.atanh`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.math.atanh.js), [`es6.math.cbrt`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.math.cbrt.js), [`es6.math.clz32`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.math.clz32.js), [`es6.math.cosh`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.math.cosh.js), [`es6.math.expm1`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.math.expm1.js), [`es6.math.fround`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.math.fround.js), [`es6.math.hypot`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.math.hypot.js), [`es6.math.imul`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.math.imul.js), [`es6.math.log10`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.math.log10.js), [`es6.math.log1p`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.math.log1p.js), [`es6.math.log2`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.math.log2.js), [`es6.math.sign`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.math.sign.js), [`es6.math.sinh`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.math.sinh.js), [`es6.math.tanh`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.math.tanh.js), [`es6.math.trunc`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.math.trunc.js).\n```js\nMath\n  .acosh(num)     -> num\n  .asinh(num)     -> num\n  .atanh(num)     -> num\n  .cbrt(num)      -> num\n  .clz32(num)     -> uint\n  .cosh(num)      -> num\n  .expm1(num)     -> num\n  .fround(num)    -> num\n  .hypot(...args) -> num\n  .imul(num, num) -> int\n  .log1p(num)     -> num\n  .log10(num)     -> num\n  .log2(num)      -> num\n  .sign(num)      -> 1 | -1 | 0 | -0 | NaN\n  .sinh(num)      -> num\n  .tanh(num)      -> num\n  .trunc(num)     -> num\n```\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js(/library)/es6/math\ncore-js(/library)/fn/math/acosh\ncore-js(/library)/fn/math/asinh\ncore-js(/library)/fn/math/atanh\ncore-js(/library)/fn/math/cbrt\ncore-js(/library)/fn/math/clz32\ncore-js(/library)/fn/math/cosh\ncore-js(/library)/fn/math/expm1\ncore-js(/library)/fn/math/fround\ncore-js(/library)/fn/math/hypot\ncore-js(/library)/fn/math/imul\ncore-js(/library)/fn/math/log1p\ncore-js(/library)/fn/math/log10\ncore-js(/library)/fn/math/log2\ncore-js(/library)/fn/math/sign\ncore-js(/library)/fn/math/sinh\ncore-js(/library)/fn/math/tanh\ncore-js(/library)/fn/math/trunc\n```\n#### ECMAScript 6: Date\nModules [`es6.date.to-string`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.date.to-string.js), ES5 features with fixes: [`es6.date.now`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.date.now.js), [`es6.date.to-iso-string`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.date.to-iso-string.js), [`es6.date.to-json`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.date.to-json.js) and [`es6.date.to-primitive`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.date.to-primitive.js).\n```js\nDate\n  .now()               -> int\n  #toISOString()       -> string\n  #toJSON()            -> string\n  #toString()          -> string\n  #@@toPrimitive(hint) -> primitive\n```\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js/es6/date\ncore-js/fn/date/to-string\ncore-js(/library)/fn/date/now\ncore-js(/library)/fn/date/to-iso-string\ncore-js(/library)/fn/date/to-json\ncore-js(/library)/fn/date/to-primitive\n```\n[*Example*](http://goo.gl/haeHLR):\n```js\nnew Date(NaN).toString(); // => 'Invalid Date'\n```\n\n#### ECMAScript 6: Promise\nModule [`es6.promise`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.promise.js).\n```js\nnew Promise(executor(resolve(var), reject(var))) -> promise\n  #then(resolved(var), rejected(var))            -> promise\n  #catch(rejected(var))                          -> promise\n  .resolve(promise | var)                        -> promise\n  .reject(var)                                   -> promise\n  .all(iterable)                                 -> promise\n  .race(iterable)                                -> promise\n```\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js(/library)/es6/promise\ncore-js(/library)/fn/promise\n```\nBasic [*example*](http://goo.gl/vGrtUC):\n```js\nfunction sleepRandom(time){\n  return new Promise(function(resolve, reject){\n    setTimeout(resolve, time * 1e3, 0 | Math.random() * 1e3);\n  });\n}\n\nconsole.log('Run');                    // => Run\nsleepRandom(5).then(function(result){\n  console.log(result);                 // => 869, after 5 sec.\n  return sleepRandom(10);\n}).then(function(result){\n  console.log(result);                 // => 202, after 10 sec.\n}).then(function(){\n  console.log('immediately after');    // => immediately after\n  throw Error('Irror!');\n}).then(function(){\n  console.log('will not be displayed');\n}).catch(x => console.log(x));         // => => Error: Irror!\n```\n`Promise.resolve` and `Promise.reject` [*example*](http://goo.gl/vr8TN3):\n```js\nPromise.resolve(42).then(x => console.log(x)); // => 42\nPromise.reject(42).catch(x => console.log(x)); // => 42\n\nPromise.resolve($.getJSON('/data.json')); // => ES6 promise\n```\n`Promise.all` [*example*](http://goo.gl/RdoDBZ):\n```js\nPromise.all([\n  'foo',\n  sleepRandom(5),\n  sleepRandom(15),\n  sleepRandom(10)             // after 15 sec:\n]).then(x => console.log(x)); // => ['foo', 956, 85, 382]\n```\n`Promise.race` [*example*](http://goo.gl/L8ovkJ):\n```js\nfunction timeLimit(promise, time){\n  return Promise.race([promise, new Promise(function(resolve, reject){\n    setTimeout(reject, time * 1e3, Error('Await > ' + time + ' sec'));\n  })]);\n}\n\ntimeLimit(sleepRandom(5), 10).then(x => console.log(x));   // => 853, after 5 sec.\ntimeLimit(sleepRandom(15), 10).catch(x => console.log(x)); // Error: Await > 10 sec\n```\nECMAScript 7 [async functions](https://tc39.github.io/ecmascript-asyncawait) [example](http://goo.gl/wnQS4j):\n```js\nvar delay = time => new Promise(resolve => setTimeout(resolve, time))\n\nasync function sleepRandom(time){\n  await delay(time * 1e3);\n  return 0 | Math.random() * 1e3;\n};\nasync function sleepError(time, msg){\n  await delay(time * 1e3);\n  throw Error(msg);\n};\n\n(async () => {\n  try {\n    console.log('Run');                // => Run\n    console.log(await sleepRandom(5)); // => 936, after 5 sec.\n    var [a, b, c] = await Promise.all([\n      sleepRandom(5),\n      sleepRandom(15),\n      sleepRandom(10)\n    ]);\n    console.log(a, b, c);              // => 210 445 71, after 15 sec.\n    await sleepError(5, 'Irror!');\n    console.log('Will not be displayed');\n  } catch(e){\n    console.log(e);                    // => Error: 'Irror!', after 5 sec.\n  }\n})();\n```\n\n##### Unhandled rejection tracking\n\nIn Node.js, like in native implementation, available events [`unhandledRejection`](https://nodejs.org/api/process.html#process_event_unhandledrejection) and [`rejectionHandled`](https://nodejs.org/api/process.html#process_event_rejectionhandled):\n```js\nprocess.on('unhandledRejection', (reason, promise) => console.log('unhandled', reason, promise));\nprocess.on('rejectionHandled', (promise) => console.log('handled', promise));\n\nvar p = Promise.reject(42);\n// unhandled 42 [object Promise]\n\nsetTimeout(() => p.catch(_ => _), 1e3);\n// handled [object Promise]\n```\nIn a browser on rejection, by default, you will see notify in the console, or you can add a custom handler and a handler on handling unhandled, [*example*](http://goo.gl/Wozskl):\n```js\nwindow.onunhandledrejection = e => console.log('unhandled', e.reason, e.promise);\nwindow.onrejectionhandled = e => console.log('handled', e.reason, e.promise);\n\nvar p = Promise.reject(42);\n// unhandled 42 [object Promise]\n\nsetTimeout(() => p.catch(_ => _), 1e3);\n// handled 42 [object Promise]\n```\n\n#### ECMAScript 6: Symbol\nModule [`es6.symbol`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.symbol.js).\n```js\nSymbol(description?)  -> symbol\n  .hasInstance        -> @@hasInstance\n  .isConcatSpreadable -> @@isConcatSpreadable\n  .iterator           -> @@iterator\n  .match              -> @@match\n  .replace            -> @@replace\n  .search             -> @@search\n  .species            -> @@species\n  .split              -> @@split\n  .toPrimitive        -> @@toPrimitive\n  .toStringTag        -> @@toStringTag\n  .unscopables        -> @@unscopables\n  .for(key)           -> symbol\n  .keyFor(symbol)     -> key\n  .useSimple()        -> void\n  .useSetter()        -> void\nObject\n  .getOwnPropertySymbols(object) -> array\n```\nAlso wrapped some methods for correct work with `Symbol` polyfill.\n```js\nObject\n  .create(proto | null, descriptors?)    -> object\n  .defineProperty(target, key, desc)     -> target\n  .defineProperties(target, descriptors) -> target\n  .getOwnPropertyDescriptor(var, key)    -> desc | undefined\n  .getOwnPropertyNames(var)              -> array\n  #propertyIsEnumerable(key)             -> bool\nJSON\n  .stringify(target, replacer?, space?) -> string | undefined\n```\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js(/library)/es6/symbol\ncore-js(/library)/fn/symbol\ncore-js(/library)/fn/symbol/has-instance\ncore-js(/library)/fn/symbol/is-concat-spreadable\ncore-js(/library)/fn/symbol/iterator\ncore-js(/library)/fn/symbol/match\ncore-js(/library)/fn/symbol/replace\ncore-js(/library)/fn/symbol/search\ncore-js(/library)/fn/symbol/species\ncore-js(/library)/fn/symbol/split\ncore-js(/library)/fn/symbol/to-primitive\ncore-js(/library)/fn/symbol/to-string-tag\ncore-js(/library)/fn/symbol/unscopables\ncore-js(/library)/fn/symbol/for\ncore-js(/library)/fn/symbol/key-for\n```\n[*Basic example*](http://goo.gl/BbvWFc):\n```js\nvar Person = (function(){\n  var NAME = Symbol('name');\n  function Person(name){\n    this[NAME] = name;\n  }\n  Person.prototype.getName = function(){\n    return this[NAME];\n  };\n  return Person;\n})();\n\nvar person = new Person('Vasya');\nconsole.log(person.getName());          // => 'Vasya'\nconsole.log(person['name']);            // => undefined\nconsole.log(person[Symbol('name')]);    // => undefined, symbols are uniq\nfor(var key in person)console.log(key); // => only 'getName', symbols are not enumerable\n```\n`Symbol.for` & `Symbol.keyFor` [*example*](http://goo.gl/0pdJjX):\n```js\nvar symbol = Symbol.for('key');\nsymbol === Symbol.for('key'); // true\nSymbol.keyFor(symbol);        // 'key'\n```\n[*Example*](http://goo.gl/mKVOQJ) with methods for getting own object keys:\n```js\nvar O = {a: 1};\nObject.defineProperty(O, 'b', {value: 2});\nO[Symbol('c')] = 3;\nObject.keys(O);                  // => ['a']\nObject.getOwnPropertyNames(O);   // => ['a', 'b']\nObject.getOwnPropertySymbols(O); // => [Symbol(c)]\nReflect.ownKeys(O);              // => ['a', 'b', Symbol(c)]\n```\n##### Caveats when using `Symbol` polyfill:\n\n* We can't add new primitive type, `Symbol` returns object.\n* `Symbol.for` and `Symbol.keyFor` can't be shimmed cross-realm.\n* By default, to hide the keys, `Symbol` polyfill defines setter in `Object.prototype`. For this reason, uncontrolled creation of symbols can cause memory leak and the `in` operator is not working correctly with `Symbol` polyfill: `Symbol() in {} // => true`.\n\nYou can disable defining setters in `Object.prototype`. [Example](http://goo.gl/N5UD7J):\n```js\nSymbol.useSimple();\nvar s1 = Symbol('s1')\n  , o1 = {};\no1[s1] = true;\nfor(var key in o1)console.log(key); // => 'Symbol(s1)_t.qamkg9f3q', w/o native Symbol\n\nSymbol.useSetter();\nvar s2 = Symbol('s2')\n  , o2 = {};\no2[s2] = true;\nfor(var key in o2)console.log(key); // nothing\n```\n* Currently, `core-js` not adds setters to `Object.prototype` for well-known symbols for correct work something like `Symbol.iterator in foo`. It can cause problems with their enumerability.\n* Some problems possible with environment exotic objects (for example, IE `localStorage`).\n\n#### ECMAScript 6: Collections\n`core-js` uses native collections in most case, just fixes methods / constructor, if it's required, and in old environment uses fast polyfill (O(1) lookup).\n#### Map\nModule [`es6.map`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.map.js).\n```js\nnew Map(iterable (entries) ?)     -> map\n  #clear()                        -> void\n  #delete(key)                    -> bool\n  #forEach(fn(val, key, @), that) -> void\n  #get(key)                       -> val\n  #has(key)                       -> bool\n  #set(key, val)                  -> @\n  #size                           -> uint\n  #values()                       -> iterator\n  #keys()                         -> iterator\n  #entries()                      -> iterator\n  #@@iterator()                   -> iterator (entries)\n```\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js(/library)/es6/map\ncore-js(/library)/fn/map\n```\n[*Examples*](http://goo.gl/GWR7NI):\n```js\nvar a = [1];\n\nvar map = new Map([['a', 1], [42, 2]]);\nmap.set(a, 3).set(true, 4);\n\nconsole.log(map.size);        // => 4\nconsole.log(map.has(a));      // => true\nconsole.log(map.has([1]));    // => false\nconsole.log(map.get(a));      // => 3\nmap.forEach(function(val, key){\n  console.log(val);           // => 1, 2, 3, 4\n  console.log(key);           // => 'a', 42, [1], true\n});\nmap.delete(a);\nconsole.log(map.size);        // => 3\nconsole.log(map.get(a));      // => undefined\nconsole.log(Array.from(map)); // => [['a', 1], [42, 2], [true, 4]]\n\nvar map = new Map([['a', 1], ['b', 2], ['c', 3]]);\n\nfor(var [key, val] of map){\n  console.log(key);                           // => 'a', 'b', 'c'\n  console.log(val);                           // => 1, 2, 3\n}\nfor(var val of map.values())console.log(val); // => 1, 2, 3\nfor(var key of map.keys())console.log(key);   // => 'a', 'b', 'c'\nfor(var [key, val] of map.entries()){\n  console.log(key);                           // => 'a', 'b', 'c'\n  console.log(val);                           // => 1, 2, 3\n}\n```\n#### Set\nModule [`es6.set`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.set.js).\n```js\nnew Set(iterable?)              -> set\n  #add(key)                     -> @\n  #clear()                      -> void\n  #delete(key)                  -> bool\n  #forEach(fn(el, el, @), that) -> void\n  #has(key)                     -> bool\n  #size                         -> uint\n  #values()                     -> iterator\n  #keys()                       -> iterator\n  #entries()                    -> iterator\n  #@@iterator()                 -> iterator (values)\n```\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js(/library)/es6/set\ncore-js(/library)/fn/set\n```\n[*Examples*](http://goo.gl/bmhLwg):\n```js\nvar set = new Set(['a', 'b', 'a', 'c']);\nset.add('d').add('b').add('e');\nconsole.log(set.size);        // => 5\nconsole.log(set.has('b'));    // => true\nset.forEach(function(it){\n  console.log(it);            // => 'a', 'b', 'c', 'd', 'e'\n});\nset.delete('b');\nconsole.log(set.size);        // => 4\nconsole.log(set.has('b'));    // => false\nconsole.log(Array.from(set)); // => ['a', 'c', 'd', 'e']\n\nvar set = new Set([1, 2, 3, 2, 1]);\n\nfor(var val of set)console.log(val);          // => 1, 2, 3\nfor(var val of set.values())console.log(val); // => 1, 2, 3\nfor(var key of set.keys())console.log(key);   // => 1, 2, 3\nfor(var [key, val] of set.entries()){\n  console.log(key);                           // => 1, 2, 3\n  console.log(val);                           // => 1, 2, 3\n}\n```\n#### WeakMap\nModule [`es6.weak-map`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.weak-map.js).\n```js\nnew WeakMap(iterable (entries) ?) -> weakmap\n  #delete(key)                    -> bool\n  #get(key)                       -> val\n  #has(key)                       -> bool\n  #set(key, val)                  -> @\n```\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js(/library)/es6/weak-map\ncore-js(/library)/fn/weak-map\n```\n[*Examples*](http://goo.gl/SILXyw):\n```js\nvar a = [1]\n  , b = [2]\n  , c = [3];\n\nvar wmap = new WeakMap([[a, 1], [b, 2]]);\nwmap.set(c, 3).set(b, 4);\nconsole.log(wmap.has(a));   // => true\nconsole.log(wmap.has([1])); // => false\nconsole.log(wmap.get(a));   // => 1\nwmap.delete(a);\nconsole.log(wmap.get(a));   // => undefined\n\n// Private properties store:\nvar Person = (function(){\n  var names = new WeakMap;\n  function Person(name){\n    names.set(this, name);\n  }\n  Person.prototype.getName = function(){\n    return names.get(this);\n  };\n  return Person;\n})();\n\nvar person = new Person('Vasya');\nconsole.log(person.getName());          // => 'Vasya'\nfor(var key in person)console.log(key); // => only 'getName'\n```\n#### WeakSet\nModule [`es6.weak-set`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.weak-set.js).\n```js\nnew WeakSet(iterable?) -> weakset\n  #add(key)            -> @\n  #delete(key)         -> bool\n  #has(key)            -> bool\n```\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js(/library)/es6/weak-set\ncore-js(/library)/fn/weak-set\n```\n[*Examples*](http://goo.gl/TdFbEx):\n```js\nvar a = [1]\n  , b = [2]\n  , c = [3];\n\nvar wset = new WeakSet([a, b, a]);\nwset.add(c).add(b).add(c);\nconsole.log(wset.has(b));   // => true\nconsole.log(wset.has([2])); // => false\nwset.delete(b);\nconsole.log(wset.has(b));   // => false\n```\n##### Caveats when using collections polyfill:\n\n* Weak-collections polyfill stores values as hidden properties of keys. It works correct and not leak in most cases. However, it is desirable to store a collection longer than its keys.\n\n#### ECMAScript 6: Typed Arrays\nImplementations and fixes `ArrayBuffer`, `DataView`, typed arrays constructors, static and prototype methods. Typed Arrays work only in environments with support descriptors (IE9+), `ArrayBuffer` and `DataView` should work anywhere.\n\nModules [`es6.typed.array-buffer`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.typed.array-buffer.js), [`es6.typed.data-view`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.typed.data-view.js), [`es6.typed.int8-array`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.typed.int8-array.js), [`es6.typed.uint8-array`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.typed.uint8-array.js), [`es6.typed.uint8-clamped-array`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.typed.uint8-clamped-array.js), [`es6.typed.int16-array`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.typed.int16-array.js), [`es6.typed.uint16-array`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.typed.uint16-array.js), [`es6.typed.int32-array`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.typed.int32-array.js), [`es6.typed.uint32-array`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.typed.uint32-array.js), [`es6.typed.float32-array`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.typed.float32-array.js) and [`es6.typed.float64-array`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.typed.float64-array.js).\n```js\nnew ArrayBuffer(length) -> buffer\n  .isView(var) -> bool\n  #slice(start = 0, end = @length) -> buffer\n  #byteLength -> uint\n\nnew DataView(buffer, byteOffset = 0, byteLength = buffer.byteLength - byteOffset) -> view\n  #getInt8(offset)                          -> int8\n  #getUint8(offset)                         -> uint8\n  #getInt16(offset, littleEndian = false)   -> int16\n  #getUint16(offset, littleEndian = false)  -> uint16\n  #getInt32(offset, littleEndian = false)   -> int32\n  #getUint32(offset, littleEndian = false)  -> uint32\n  #getFloat32(offset, littleEndian = false) -> float32\n  #getFloat64(offset, littleEndian = false) -> float64\n  #setInt8(offset, value)                          -> void\n  #setUint8(offset, value)                         -> void\n  #setInt16(offset, value, littleEndian = false)   -> void\n  #setUint16(offset, value, littleEndian = false)  -> void\n  #setInt32(offset, value, littleEndian = false)   -> void\n  #setUint32(offset, value, littleEndian = false)  -> void\n  #setFloat32(offset, value, littleEndian = false) -> void\n  #setFloat64(offset, value, littleEndian = false) -> void\n  #buffer     -> buffer\n  #byteLength -> uint\n  #byteOffset -> uint\n\n{\n  Int8Array,\n  Uint8Array,\n  Uint8ClampedArray,\n  Int16Array,\n  Uint16Array,\n  Int32Array,\n  Uint32Array,\n  Float32Array,\n  Float64Array\n}\n  new %TypedArray%(length)    -> typed\n  new %TypedArray%(typed)     -> typed\n  new %TypedArray%(arrayLike) -> typed\n  new %TypedArray%(iterable)  -> typed\n  new %TypedArray%(buffer, byteOffset = 0, length = (buffer.byteLength - byteOffset) / @BYTES_PER_ELEMENT) -> typed\n  .BYTES_PER_ELEMENT -> uint\n  .from(arrayLike | iterable, mapFn(val, index)?, that) -> typed\n  .of(...args) -> typed\n  #BYTES_PER_ELEMENT -> uint\n  #copyWithin(target = 0, start = 0, end = @length) -> @\n  #every(fn(val, index, @), that) -> bool\n  #fill(val, start = 0, end = @length) -> @\n  #filter(fn(val, index, @), that) -> typed\n  #find(fn(val, index, @), that) -> val\n  #findIndex(fn(val, index, @), that) -> index\n  #forEach(fn(val, index, @), that) -> void\n  #indexOf(var, from?) -> int\n  #join(string = ',') -> string\n  #lastIndexOf(var, from?) -> int\n  #map(fn(val, index, @), that) -> typed\n  #reduce(fn(memo, val, index, @), memo?) -> var\n  #reduceRight(fn(memo, val, index, @), memo?) -> var\n  #reverse() -> @\n  #set(arrayLike, offset = 0) -> void\n  #slice(start = 0, end = @length) -> typed\n  #some(fn(val, index, @), that) -> bool\n  #sort(fn(a, b)?) -> @\n  #subarray(start = 0, end = @length) -> typed\n  #toString() -> string\n  #toLocaleString() -> string\n  #values()     -> iterator\n  #keys()       -> iterator\n  #entries()    -> iterator\n  #@@iterator() -> iterator (values)\n  #buffer     -> buffer\n  #byteLength -> uint\n  #byteOffset -> uint\n  #length     -> uint\n```\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js(/library)/es6/typed\ncore-js(/library)/fn/typed\ncore-js(/library)/fn/typed/array-buffer\ncore-js(/library)/fn/typed/data-view\ncore-js(/library)/fn/typed/int8-array\ncore-js(/library)/fn/typed/uint8-array\ncore-js(/library)/fn/typed/uint8-clamped-array\ncore-js(/library)/fn/typed/int16-array\ncore-js(/library)/fn/typed/uint16-array\ncore-js(/library)/fn/typed/int32-array\ncore-js(/library)/fn/typed/uint32-array\ncore-js(/library)/fn/typed/float32-array\ncore-js(/library)/fn/typed/float64-array\n```\n[*Examples*](http://goo.gl/yla75z):\n```js\nnew Int32Array(4);                          // => [0, 0, 0, 0]\nnew Uint8ClampedArray([1, 2, 3, 666]);      // => [1, 2, 3, 255]\nnew Float32Array(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]\n\nvar buffer = new ArrayBuffer(8);\nvar view   = new DataView(buffer);\nview.setFloat64(0, 123.456, true);\nnew Uint8Array(buffer.slice(4)); // => [47, 221, 94, 64]\n\nInt8Array.of(1, 1.5, 5.7, 745);      // => [1, 1, 5, -23]\nUint8Array.from([1, 1.5, 5.7, 745]); // => [1, 1, 5, 233]\n\nvar typed = new Uint8Array([1, 2, 3]);\n\nvar a = typed.slice(1);    // => [2, 3]\ntyped.buffer === a.buffer; // => false\nvar b = typed.subarray(1); // => [2, 3]\ntyped.buffer === b.buffer; // => true\n\ntyped.filter(it => it % 2); // => [1, 3]\ntyped.map(it => it * 1.5);  // => [1, 3, 4]\n\nfor(var val of typed)console.log(val);          // => 1, 2, 3\nfor(var val of typed.values())console.log(val); // => 1, 2, 3\nfor(var key of typed.keys())console.log(key);   // => 0, 1, 2\nfor(var [key, val] of typed.entries()){\n  console.log(key);                             // => 0, 1, 2\n  console.log(val);                             // => 1, 2, 3\n}\n```\n##### Caveats when using typed arrays:\n\n* Typed Arrays polyfills works completely how should work by the spec, but because of internal use getter / setters on each instance, is slow and consumes significant memory. However, typed arrays polyfills required mainly for IE9 (and for `Uint8ClampedArray` in IE10 and early IE11), all modern engines have native typed arrays and requires only constructors fixes and methods.\n* The current version hasn't special entry points for methods, they can be added only with constructors. It can be added in the future.\n* In the `library` version we can't pollute native prototypes, so prototype methods available as constructors static.\n\n#### ECMAScript 6: Reflect\nModules [`es6.reflect.apply`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.reflect.apply.js), [`es6.reflect.construct`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.reflect.construct.js), [`es6.reflect.define-property`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.reflect.define-property.js), [`es6.reflect.delete-property`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.reflect.delete-property.js), [`es6.reflect.enumerate`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.reflect.enumerate.js), [`es6.reflect.get`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.reflect.get.js), [`es6.reflect.get-own-property-descriptor`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.reflect.get-own-property-descriptor.js), [`es6.reflect.get-prototype-of`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.reflect.get-prototype-of.js), [`es6.reflect.has`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.reflect.has.js), [`es6.reflect.is-extensible`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.reflect.is-extensible.js), [`es6.reflect.own-keys`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.reflect.own-keys.js), [`es6.reflect.prevent-extensions`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.reflect.prevent-extensions.js), [`es6.reflect.set`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.reflect.set.js), [`es6.reflect.set-prototype-of`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es6.reflect.set-prototype-of.js).\n```js\nReflect\n  .apply(target, thisArgument, argumentsList) -> var\n  .construct(target, argumentsList, newTarget?) -> object\n  .defineProperty(target, propertyKey, attributes) -> bool\n  .deleteProperty(target, propertyKey) -> bool\n  .enumerate(target) -> iterator (removed from the spec and will be removed from core-js@3)\n  .get(target, propertyKey, receiver?) -> var\n  .getOwnPropertyDescriptor(target, propertyKey) -> desc\n  .getPrototypeOf(target) -> object | null\n  .has(target, propertyKey) -> bool\n  .isExtensible(target) -> bool\n  .ownKeys(target) -> array\n  .preventExtensions(target) -> bool\n  .set(target, propertyKey, V, receiver?) -> bool\n  .setPrototypeOf(target, proto) -> bool (required __proto__ - IE11+)\n```\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js(/library)/es6/reflect\ncore-js(/library)/fn/reflect\ncore-js(/library)/fn/reflect/apply\ncore-js(/library)/fn/reflect/construct\ncore-js(/library)/fn/reflect/define-property\ncore-js(/library)/fn/reflect/delete-property\ncore-js(/library)/fn/reflect/enumerate (deprecated and will be removed from the next major release)\ncore-js(/library)/fn/reflect/get\ncore-js(/library)/fn/reflect/get-own-property-descriptor\ncore-js(/library)/fn/reflect/get-prototype-of\ncore-js(/library)/fn/reflect/has\ncore-js(/library)/fn/reflect/is-extensible\ncore-js(/library)/fn/reflect/own-keys\ncore-js(/library)/fn/reflect/prevent-extensions\ncore-js(/library)/fn/reflect/set\ncore-js(/library)/fn/reflect/set-prototype-of\n```\n[*Examples*](http://goo.gl/gVT0cH):\n```js\nvar O = {a: 1};\nObject.defineProperty(O, 'b', {value: 2});\nO[Symbol('c')] = 3;\nReflect.ownKeys(O); // => ['a', 'b', Symbol(c)]\n\nfunction C(a, b){\n  this.c = a + b;\n}\n\nvar instance = Reflect.construct(C, [20, 22]);\ninstance.c; // => 42\n```\n\n### ECMAScript 7+ proposals\n[The TC39 process.](https://tc39.github.io/process-document/)\n\n[*CommonJS entry points:*](#commonjs)\n```\ncore-js(/library)/es7\ncore-js(/library)/es7/array\ncore-js(/library)/es7/global\ncore-js(/library)/es7/string\ncore-js(/library)/es7/map\ncore-js(/library)/es7/set\ncore-js(/library)/es7/error\ncore-js(/library)/es7/math\ncore-js(/library)/es7/system\ncore-js(/library)/es7/symbol\ncore-js(/library)/es7/reflect\ncore-js(/library)/es7/observable\n```\n`core-js/stage/4` entry point contains only stage 4 proposals, `core-js/stage/3` - stage 3 and stage 4, etc.\n#### Stage 4 proposals\n\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/stage/4\n```\n* `{Array, %TypedArray%}#includes` [proposal](https://github.com/tc39/Array.prototype.includes) - module [`es7.array.includes`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.array.includes.js), `%TypedArray%` version in modules from [this section](#ecmascript-6-typed-arrays).\n```js\nArray\n  #includes(var, from?) -> bool\n{\n  Int8Array,\n  Uint8Array,\n  Uint8ClampedArray,\n  Int16Array,\n  Uint16Array,\n  Int32Array,\n  Uint32Array,\n  Float32Array,\n  Float64Array\n}\n  #includes(var, from?) -> bool\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/array/includes\n```\n[*Examples*](http://goo.gl/2Gq4ma):\n```js\n[1, 2, 3].includes(2);        // => true\n[1, 2, 3].includes(4);        // => false\n[1, 2, 3].includes(2, 2);     // => false\n\n[NaN].indexOf(NaN);           // => -1\n[NaN].includes(NaN);          // => true\nArray(1).indexOf(undefined);  // => -1\nArray(1).includes(undefined); // => true\n```\n* `Object.values`, `Object.entries` [proposal](https://github.com/tc39/proposal-object-values-entries) - modules [`es7.object.values`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.object.values.js), [`es7.object.entries`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.object.entries.js)\n```js\nObject\n  .values(object) -> array\n  .entries(object) -> array\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/object/values\ncore-js(/library)/fn/object/entries\n```\n[*Examples*](http://goo.gl/6kuGOn):\n```js\nObject.values({a: 1, b: 2, c: 3});  // => [1, 2, 3]\nObject.entries({a: 1, b: 2, c: 3}); // => [['a', 1], ['b', 2], ['c', 3]]\n\nfor(let [key, value] of Object.entries({a: 1, b: 2, c: 3})){\n  console.log(key);   // => 'a', 'b', 'c'\n  console.log(value); // => 1, 2, 3\n}\n```\n* `Object.getOwnPropertyDescriptors` [proposal](https://github.com/tc39/proposal-object-getownpropertydescriptors) - module [`es7.object.get-own-property-descriptors`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.object.get-own-property-descriptors.js)\n```js\nObject\n  .getOwnPropertyDescriptors(object) -> object\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/object/get-own-property-descriptors\n```\n*Examples*:\n```js\n// Shallow object cloning with prototype and descriptors:\nvar copy = Object.create(Object.getPrototypeOf(O), Object.getOwnPropertyDescriptors(O));\n// Mixin:\nObject.defineProperties(target, Object.getOwnPropertyDescriptors(source));\n```\n* `String#padStart`, `String#padEnd` [proposal](https://github.com/tc39/proposal-string-pad-start-end) - modules [`es7.string.pad-start`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.string.pad-start.js), [`es7.string.pad-end`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.string.pad-end.js)\n```js\nString\n  #padStart(length, fillStr = ' ') -> string\n  #padEnd(length, fillStr = ' ') -> string\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/string/pad-start\ncore-js(/library)/fn/string/pad-end\ncore-js(/library)/fn/string/virtual/pad-start\ncore-js(/library)/fn/string/virtual/pad-end\n```\n[*Examples*](http://goo.gl/hK5ccv):\n```js\n'hello'.padStart(10);         // => '     hello'\n'hello'.padStart(10, '1234'); // => '12341hello'\n'hello'.padEnd(10);           // => 'hello     '\n'hello'.padEnd(10, '1234');   // => 'hello12341'\n```\n* `Object#__(define|lookup)[GS]etter__`, [annex B ES2017](https://github.com/tc39/ecma262/pull/381), but we haven't special namespace for that - modules [`es7.object.define-setter`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.object.define-setter.js), [`es7.object.define-getter`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.object.define-getter.js), [`es7.object.lookup-setter`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.object.lookup-setter.js) and [`es7.object.lookup-getter`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.object.lookup-getter.js).\n```js\nObject\n  #__defineSetter__(key, fn) -> void\n  #__defineGetter__(key, fn) -> void\n  #__lookupSetter__(key) -> fn | void\n  #__lookupGetter__(key) -> fn | void\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/object/define-getter\ncore-js(/library)/fn/object/define-setter\ncore-js(/library)/fn/object/lookup-getter\ncore-js(/library)/fn/object/lookup-setter\n```\n\n#### Stage 3 proposals\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/stage/3\n```\n* `global` [proposal](https://github.com/tc39/proposal-global) - modules [`es7.global`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.global.js) and [`es7.system.global`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.system.global.js) (obsolete)\n```js\nglobal -> object\nSystem\n  .global -> object (obsolete)\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/global\ncore-js(/library)/fn/system/global (obsolete)\n```\n[*Examples*](http://goo.gl/gEqMl7):\n```js\nglobal.Array === Array; // => true\n```\n* `Promise#finally` [proposal](https://github.com/tc39/proposal-promise-finally) - module [`es7.promise.finally`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.promise.finally.js)\n```js\nPromise\n  #finally(onFinally()) -> promise\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/promise/finally\n```\n[*Examples*](https://goo.gl/AhyBbJ):\n```js\nPromise.resolve(42).finally(() => console.log('You will see it anyway'));\n\nPromise.reject(42).finally(() => console.log('You will see it anyway'));\n```\n\n#### Stage 2 proposals\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/stage/2\n```\n* `Symbol.asyncIterator` for [async iteration proposal](https://github.com/tc39/proposal-async-iteration) - module [`es7.symbol.async-iterator`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.symbol.async-iterator.js)\n```js\nSymbol\n  .asyncIterator -> @@asyncIterator\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/symbol/async-iterator\n```\n* `String#trimLeft`, `String#trimRight` / `String#trimStart`, `String#trimEnd` [proposal](https://github.com/sebmarkbage/ecmascript-string-left-right-trim) - modules [`es7.string.trim-left`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.string.trim-right.js), [`es7.string.trim-right`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.string.trim-right.js)\n```js\nString\n  #trimLeft()  -> string\n  #trimRight() -> string\n  #trimStart() -> string\n  #trimEnd()   -> string\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/string/trim-start\ncore-js(/library)/fn/string/trim-end\ncore-js(/library)/fn/string/trim-left\ncore-js(/library)/fn/string/trim-right\ncore-js(/library)/fn/string/virtual/trim-start\ncore-js(/library)/fn/string/virtual/trim-end\ncore-js(/library)/fn/string/virtual/trim-left\ncore-js(/library)/fn/string/virtual/trim-right\n```\n[*Examples*](http://goo.gl/Er5lMJ):\n```js\n'   hello   '.trimLeft();  // => 'hello   '\n'   hello   '.trimRight(); // => '   hello'\n```\n\n#### Stage 1 proposals\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/stage/1\n```\n* `Promise.try` [proposal](https://github.com/tc39/proposal-promise-try) - module [`es7.promise.try`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.promise.try.js)\n```js\nPromise\n  .try(function()) -> promise\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/promise/try\n```\n[*Examples*](https://goo.gl/k5GGRo):\n```js\nPromise.try(() => 42).then(it => console.log(`Promise, resolved as ${it}`));\n\nPromise.try(() => { throw 42; }).catch(it => console.log(`Promise, rejected as ${it}`));\n```\n* `Array#flatten` and `Array#flatMap` [proposal](https://tc39.github.io/proposal-flatMap) - modules [`es7.array.flatten`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.array.flatten.js) and [`es7.array.flat-map`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.array.flat-map.js)\n```js\nArray\n  #flatten(depthArg = 1) -> array\n  #flatMap(fn(val, key, @), that) -> array\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/array/flatten\ncore-js(/library)/fn/array/flatMap\ncore-js(/library)/fn/array/virtual/flatten\ncore-js(/library)/fn/array/virtual/flatMap\n```\n[*Examples*](https://goo.gl/jTXsZi):\n```js\n[1, [2, 3], [4, 5]].flatten();    // => [1, 2, 3, 4, 5]\n[1, [2, [3, [4]]], 5].flatten();  // => [1, 2, [3, [4]], 5]\n[1, [2, [3, [4]]], 5].flatten(3); // => [1, 2, 3, 4, 5]\n\n[{a: 1, b: 2}, {a: 3, b: 4}, {a: 5, b: 6}].flatMap(it => [it.a, it.b]); // => [1, 2, 3, 4, 5, 6]\n```\n* `.of` and `.from` methods on collection constructors [proposal](https://github.com/tc39/proposal-setmap-offrom) - modules [`es7.set.of`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.set.of.js), [`es7.set.from`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.set.from.js), [`es7.map.of`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.map.of.js), [`es7.map.from`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.map.from.js), [`es7.weak-set.of`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.weak-set.of.js), [`es7.weak-set.from`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.weak-set.from.js), [`es7.weak-map.of`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.weak-map.of.js), [`es7.weak-map.from`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.weak-map.from.js)\n```js\nSet\n  .of(...args) -> set\n  .from(iterable, mapFn(val, index)?, that?) -> set\nMap\n  .of(...args) -> map\n  .from(iterable, mapFn(val, index)?, that?) -> map\nWeakSet\n  .of(...args) -> weakset\n  .from(iterable, mapFn(val, index)?, that?) -> weakset\nWeakMap\n  .of(...args) -> weakmap\n  .from(iterable, mapFn(val, index)?, that?) -> weakmap\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/set/of\ncore-js(/library)/fn/set/from\ncore-js(/library)/fn/map/of\ncore-js(/library)/fn/map/from\ncore-js(/library)/fn/weak-set/of\ncore-js(/library)/fn/weak-set/from\ncore-js(/library)/fn/weak-map/of\ncore-js(/library)/fn/weak-map/from\n```\n[*Examples*](https://goo.gl/mSC7eU):\n```js\nSet.of(1, 2, 3, 2, 1); // => Set {1, 2, 3}\n\nMap.from([[1, 2], [3, 4]], ([key, val]) => [key ** 2, val ** 2]); // => Map {1: 4, 9: 16}\n```\n* `String#matchAll` [proposal](https://github.com/tc39/String.prototype.matchAll) - module [`es7.string.match-all`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.string.match-all.js)\n```js\nString\n  #matchAll(regexp) -> iterator\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/string/match-all\ncore-js(/library)/fn/string/virtual/match-all\n```\n[*Examples*](http://goo.gl/6kp9EB):\n```js\nfor(let [_, d, D] of '1111a2b3cccc'.matchAll(/(\\d)(\\D)/)){\n  console.log(d, D); // => 1 a, 2 b, 3 c\n}\n```\n* `Observable` [proposal](https://github.com/zenparsing/es-observable) - modules [`es7.observable`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.observable.js) and [`es7.symbol.observable`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.symbol.observable.js)\n```js\nnew Observable(fn)             -> observable\n  #subscribe(observer)         -> subscription\n  #forEach(fn)                 -> promise\n  #@@observable()              -> @\n  .of(...items)                -> observable\n  .from(observable | iterable) -> observable\n  .@@species                   -> @\nSymbol\n  .observable                  -> @@observable\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/observable\ncore-js(/library)/fn/symbol/observable\n```\n[*Examples*](http://goo.gl/1LDywi):\n```js\nnew Observable(observer => {\n  observer.next('hello');\n  observer.next('world');\n  observer.complete();\n}).forEach(it => console.log(it))\n  .then(_ => console.log('!'));\n```\n* `Math.{clamp, DEG_PER_RAD, degrees, fscale, rad-per-deg, radians, scale}` \n  [proposal](https://github.com/rwaldron/proposal-math-extensions) - modules \n  [`es7.math.clamp`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.math.clamp.js), \n  [`es7.math.DEG_PER_RAD`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.math.DEG_PER_RAD.js), \n  [`es7.math.degrees`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.math.degrees.js),\n  [`es7.math.fscale`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.math.fscale.js), \n  [`es7.math.RAD_PER_DEG`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.math.RAD_PER_DEG.js), \n  [`es7.math.radians`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.math.radians.js) and\n  [`es7.math.scale`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.math.scale.js)\n```js\nMath\n  .DEG_PER_RAD -> number\n  .RAD_PER_DEG -> number\n  .clamp(x, lower, upper) -> number\n  .degrees(radians) -> number\n  .fscale(x, inLow, inHigh, outLow, outHigh) -> number\n  .radians(degrees) -> number\n  .scale(x, inLow, inHigh, outLow, outHigh) -> number\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/math/clamp\ncore-js(/library)/fn/math/deg-per-rad\ncore-js(/library)/fn/math/degrees\ncore-js(/library)/fn/math/fscale\ncore-js(/library)/fn/math/rad-per-deg\ncore-js(/library)/fn/math/radians\ncore-js(/library)/fn/math/scale\n```\n* `Math.signbit` [proposal](http://jfbastien.github.io/papers/Math.signbit.html) - module [`es7.math.signbit`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.math.signbit.js)\n```js\nMath\n  .signbit(x) -> bool\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/math/signbit\n```\n[*Examples*](http://es6.zloirock.ru/):\n```js\nMath.signbit(NaN); // => NaN\nMath.signbit(1);   // => true\nMath.signbit(-1);  // => false\nMath.signbit(0);   // => true\nMath.signbit(-0);  // => false\n```\n\n#### Stage 0 proposals\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/stage/0\n```\n* `String#at` [proposal](https://github.com/mathiasbynens/String.prototype.at) - module [`es7.string.at`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.string.at.js)\n```js\nString\n  #at(index) -> string\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/string/at\ncore-js(/library)/fn/string/virtual/at\n```\n[*Examples*](http://goo.gl/XluXI8):\n```js\n'a𠮷b'.at(1);        // => '𠮷'\n'a𠮷b'.at(1).length; // => 2\n```\n* `Map#toJSON`, `Set#toJSON` [proposal](https://github.com/DavidBruant/Map-Set.prototype.toJSON) - modules [`es7.map.to-json`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.map.to-json.js), [`es7.set.to-json`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.set.to-json.js) (rejected and will be removed from `core-js@3`)\n```js\nMap\n  #toJSON() -> array (rejected and will be removed from core-js@3)\nSet\n  #toJSON() -> array (rejected and will be removed from core-js@3)\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/map\ncore-js(/library)/fn/set\n```\n* `Error.isError` [proposal](https://github.com/ljharb/proposal-is-error) - module [`es7.error.is-error`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.error.is-error.js) (withdrawn and will be removed from `core-js@3`)\n```js\nError\n  .isError(it) -> bool (withdrawn and will be removed from core-js@3)\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/error/is-error\n```\n* `Math.{iaddh, isubh, imulh, umulh}` [proposal](https://gist.github.com/BrendanEich/4294d5c212a6d2254703) - modules [`es7.math.iaddh`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.math.iaddh.js), [`es7.math.isubh`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.math.isubh.js), [`es7.math.imulh`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.math.imulh.js) and [`es7.math.umulh`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.math.umulh.js)\n```js\nMath\n  .iaddh(lo0, hi0, lo1, hi1) -> int32\n  .isubh(lo0, hi0, lo1, hi1) -> int32\n  .imulh(a, b) -> int32\n  .umulh(a, b) -> uint32\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/math/iaddh\ncore-js(/library)/fn/math/isubh\ncore-js(/library)/fn/math/imulh\ncore-js(/library)/fn/math/umulh\n```\n* `glogal.asap`, [TC39 discussion](https://github.com/rwaldron/tc39-notes/blob/master/es6/2014-09/sept-25.md#510-globalasap-for-enqueuing-a-microtask), module [`es7.asap`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.asap.js)\n```js\nasap(fn) -> void\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/asap\n```\n[*Examples*](http://goo.gl/tx3SRK):\n```js\nasap(() => console.log('called as microtask'));\n```\n\n#### Pre-stage 0 proposals\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/stage/pre\n```\n* `Reflect` metadata [proposal](https://github.com/jonathandturner/decorators/blob/master/specs/metadata.md) - modules [`es7.reflect.define-metadata`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.reflect.define-metadata.js), [`es7.reflect.delete-metadata`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.reflect.delete-metadata.js), [`es7.reflect.get-metadata`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.reflect.get-metadata.js), [`es7.reflect.get-metadata-keys`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.reflect.get-metadata-keys.js), [`es7.reflect.get-own-metadata`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.reflect.get-own-metadata.js), [`es7.reflect.get-own-metadata-keys`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.reflect.get-own-metadata-keys.js), [`es7.reflect.has-metadata`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.reflect.has-metadata.js), [`es7.reflect.has-own-metadata`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.reflect.has-own-metadata.js) and [`es7.reflect.metadata`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/es7.reflect.metadata.js).\n```js\nReflect\n  .defineMetadata(metadataKey, metadataValue, target, propertyKey?) -> void\n  .getMetadata(metadataKey, target, propertyKey?) -> var\n  .getOwnMetadata(metadataKey, target, propertyKey?) -> var\n  .hasMetadata(metadataKey, target, propertyKey?) -> bool\n  .hasOwnMetadata(metadataKey, target, propertyKey?) -> bool\n  .deleteMetadata(metadataKey, target, propertyKey?) -> bool\n  .getMetadataKeys(target, propertyKey?) -> array\n  .getOwnMetadataKeys(target, propertyKey?) -> array\n  .metadata(metadataKey, metadataValue) -> decorator(target, targetKey?) -> void\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/reflect/define-metadata\ncore-js(/library)/fn/reflect/delete-metadata\ncore-js(/library)/fn/reflect/get-metadata\ncore-js(/library)/fn/reflect/get-metadata-keys\ncore-js(/library)/fn/reflect/get-own-metadata\ncore-js(/library)/fn/reflect/get-own-metadata-keys\ncore-js(/library)/fn/reflect/has-metadata\ncore-js(/library)/fn/reflect/has-own-metadata\ncore-js(/library)/fn/reflect/metadata\n```\n[*Examples*](http://goo.gl/KCo3PS):\n```js\nvar O = {};\nReflect.defineMetadata('foo', 'bar', O);\nReflect.ownKeys(O);               // => []\nReflect.getOwnMetadataKeys(O);    // => ['foo']\nReflect.getOwnMetadata('foo', O); // => 'bar'\n```\n\n### Web standards\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/web\n```\n#### setTimeout / setInterval\nModule [`web.timers`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/web.timers.js). Additional arguments fix for IE9-.\n```js\nsetTimeout(fn(...args), time, ...args) -> id\nsetInterval(fn(...args), time, ...args) -> id\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/web/timers\ncore-js(/library)/fn/set-timeout\ncore-js(/library)/fn/set-interval\n```\n```js\n// Before:\nsetTimeout(log.bind(null, 42), 1000);\n// After:\nsetTimeout(log, 1000, 42);\n```\n#### setImmediate\nModule [`web.immediate`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/web.immediate.js). [`setImmediate` proposal](https://developer.mozilla.org/en-US/docs/Web/API/Window.setImmediate) polyfill.\n```js\nsetImmediate(fn(...args), ...args) -> id\nclearImmediate(id) -> void\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/web/immediate\ncore-js(/library)/fn/set-immediate\ncore-js(/library)/fn/clear-immediate\n```\n[*Examples*](http://goo.gl/6nXGrx):\n```js\nsetImmediate(function(arg1, arg2){\n  console.log(arg1, arg2); // => Message will be displayed with minimum delay\n}, 'Message will be displayed', 'with minimum delay');\n\nclearImmediate(setImmediate(function(){\n  console.log('Message will not be displayed');\n}));\n```\n#### Iterable DOM collections\nSome DOM collections should have [iterable interface](https://heycam.github.io/webidl/#idl-iterable) or should be [inherited from `Array`](https://heycam.github.io/webidl/#LegacyArrayClass). That mean they should have `keys`, `values`, `entries` and `@@iterator` methods for iteration. So add them. Module [`web.dom.iterable`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/web.dom.iterable.js):\n```js\n{\n  CSSRuleList,\n  CSSStyleDeclaration,\n  CSSValueList,\n  ClientRectList,\n  DOMRectList,\n  DOMStringList,\n  DOMTokenList,\n  DataTransferItemList,\n  FileList,\n  HTMLAllCollection,\n  HTMLCollection,\n  HTMLFormElement,\n  HTMLSelectElement,\n  MediaList,\n  MimeTypeArray,\n  NamedNodeMap,\n  NodeList,\n  PaintRequestList,\n  Plugin,\n  PluginArray,\n  SVGLengthList,\n  SVGNumberList,\n  SVGPathSegList,\n  SVGPointList,\n  SVGStringList,\n  SVGTransformList,\n  SourceBufferList,\n  StyleSheetList,\n  TextTrackCueList,\n  TextTrackList,\n  TouchList\n}\n  #@@iterator() -> iterator (values)\n\n{\n  DOMTokenList,\n  NodeList\n}\n  #values()  -> iterator\n  #keys()    -> iterator\n  #entries() -> iterator\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/web/dom-collections\ncore-js(/library)/fn/dom-collections/iterator\n```\n[*Examples*](http://goo.gl/lfXVFl):\n```js\nfor(var {id} of document.querySelectorAll('*')){\n  if(id)console.log(id);\n}\n\nfor(var [index, {id}] of document.querySelectorAll('*').entries()){\n  if(id)console.log(index, id);\n}\n```\n### Non-standard\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/core\n```\n#### Object\nModules [`core.object.is-object`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/core.object.is-object.js), [`core.object.classof`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/core.object.classof.js), [`core.object.define`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/core.object.define.js), [`core.object.make`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/core.object.make.js).\n```js\nObject\n  .isObject(var) -> bool\n  .classof(var) -> string\n  .define(target, mixin) -> target\n  .make(proto | null, mixin?) -> object\n```\n\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/core/object\ncore-js(/library)/fn/object/is-object\ncore-js(/library)/fn/object/define\ncore-js(/library)/fn/object/make\n```\nObject classify [*examples*](http://goo.gl/YZQmGo):\n```js\nObject.isObject({});    // => true\nObject.isObject(isNaN); // => true\nObject.isObject(null);  // => false\n\nvar classof = Object.classof;\n\nclassof(null);                 // => 'Null'\nclassof(undefined);            // => 'Undefined'\nclassof(1);                    // => 'Number'\nclassof(true);                 // => 'Boolean'\nclassof('string');             // => 'String'\nclassof(Symbol());             // => 'Symbol'\n\nclassof(new Number(1));        // => 'Number'\nclassof(new Boolean(true));    // => 'Boolean'\nclassof(new String('string')); // => 'String'\n\nvar fn   = function(){}\n  , list = (function(){return arguments})(1, 2, 3);\n\nclassof({});                   // => 'Object'\nclassof(fn);                   // => 'Function'\nclassof([]);                   // => 'Array'\nclassof(list);                 // => 'Arguments'\nclassof(/./);                  // => 'RegExp'\nclassof(new TypeError);        // => 'Error'\n\nclassof(new Set);              // => 'Set'\nclassof(new Map);              // => 'Map'\nclassof(new WeakSet);          // => 'WeakSet'\nclassof(new WeakMap);          // => 'WeakMap'\nclassof(new Promise(fn));      // => 'Promise'\n\nclassof([].values());          // => 'Array Iterator'\nclassof(new Set().values());   // => 'Set Iterator'\nclassof(new Map().values());   // => 'Map Iterator'\n\nclassof(Math);                 // => 'Math'\nclassof(JSON);                 // => 'JSON'\n\nfunction Example(){}\nExample.prototype[Symbol.toStringTag] = 'Example';\n\nclassof(new Example);          // => 'Example'\n```\n`Object.define` and `Object.make` [*examples*](http://goo.gl/rtpD5Z):\n```js\n// Before:\nObject.defineProperty(target, 'c', {\n  enumerable: true,\n  configurable: true,\n  get: function(){\n    return this.a + this.b;\n  }\n});\n\n// After:\nObject.define(target, {\n  get c(){\n    return this.a + this.b;\n  }\n});\n\n// Shallow object cloning with prototype and descriptors:\nvar copy = Object.make(Object.getPrototypeOf(src), src);\n\n// Simple inheritance:\nfunction Vector2D(x, y){\n  this.x = x;\n  this.y = y;\n}\nObject.define(Vector2D.prototype, {\n  get xy(){\n    return Math.hypot(this.x, this.y);\n  }\n});\nfunction Vector3D(x, y, z){\n  Vector2D.apply(this, arguments);\n  this.z = z;\n}\nVector3D.prototype = Object.make(Vector2D.prototype, {\n  constructor: Vector3D,\n  get xyz(){\n    return Math.hypot(this.x, this.y, this.z);\n  }\n});\n\nvar vector = new Vector3D(9, 12, 20);\nconsole.log(vector.xy);  // => 15\nconsole.log(vector.xyz); // => 25\nvector.y++;\nconsole.log(vector.xy);  // => 15.811388300841896\nconsole.log(vector.xyz); // => 25.495097567963924\n```\n#### Dict\nModule [`core.dict`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/core.dict.js). Based on [TC39 discuss](https://github.com/rwaldron/tc39-notes/blob/master/es6/2012-11/nov-29.md#collection-apis-review) / [strawman](http://wiki.ecmascript.org/doku.php?id=harmony:modules_standard#dictionaries).\n```js\n[new] Dict(iterable (entries) | object ?) -> dict\n  .isDict(var) -> bool\n  .values(object) -> iterator\n  .keys(object) -> iterator\n  .entries(object) -> iterator (entries)\n  .has(object, key) -> bool\n  .get(object, key) -> val\n  .set(object, key, value) -> object\n  .forEach(object, fn(val, key, @), that) -> void\n  .map(object, fn(val, key, @), that) -> new @\n  .mapPairs(object, fn(val, key, @), that) -> new @\n  .filter(object, fn(val, key, @), that) -> new @\n  .some(object, fn(val, key, @), that) -> bool\n  .every(object, fn(val, key, @), that) -> bool\n  .find(object, fn(val, key, @), that) -> val\n  .findKey(object, fn(val, key, @), that) -> key\n  .keyOf(object, var) -> key\n  .includes(object, var) -> bool\n  .reduce(object, fn(memo, val, key, @), memo?) -> var\n```\n\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/core/dict\ncore-js(/library)/fn/dict\n```\n`Dict` create object without prototype from iterable or simple object.\n\n[*Examples*](http://goo.gl/pnp8Vr):\n```js\nvar map = new Map([['a', 1], ['b', 2], ['c', 3]]);\n\nDict();                    // => {__proto__: null}\nDict({a: 1, b: 2, c: 3});  // => {__proto__: null, a: 1, b: 2, c: 3}\nDict(map);                 // => {__proto__: null, a: 1, b: 2, c: 3}\nDict([1, 2, 3].entries()); // => {__proto__: null, 0: 1, 1: 2, 2: 3}\n\nvar dict = Dict({a: 42});\ndict instanceof Object;   // => false\ndict.a;                   // => 42\ndict.toString;            // => undefined\n'a' in dict;              // => true\n'hasOwnProperty' in dict; // => false\n\nDict.isDict({});     // => false\nDict.isDict(Dict()); // => true\n```\n`Dict.keys`, `Dict.values` and `Dict.entries` returns iterators for objects.\n\n[*Examples*](http://goo.gl/xAvECH):\n```js\nvar dict = {a: 1, b: 2, c: 3};\n\nfor(var key of Dict.keys(dict))console.log(key); // => 'a', 'b', 'c'\n\nfor(var val of Dict.values(dict))console.log(val); // => 1, 2, 3\n\nfor(var [key, val] of Dict.entries(dict)){\n  console.log(key); // => 'a', 'b', 'c'\n  console.log(val); // => 1, 2, 3\n}\n\nnew Map(Dict.entries(dict)); // => Map {a: 1, b: 2, c: 3}\n```\nBasic dict operations for objects with prototype [*examples*](http://goo.gl/B28UnG):\n```js\n'q' in {q: 1};            // => true\n'toString' in {};         // => true\n\nDict.has({q: 1}, 'q');    // => true\nDict.has({}, 'toString'); // => false\n\n({q: 1})['q'];            // => 1\n({}).toString;            // => function toString(){ [native code] }\n\nDict.get({q: 1}, 'q');    // => 1\nDict.get({}, 'toString'); // => undefined\n\nvar O = {};\nO['q'] = 1;\nO['q'];         // => 1\nO['__proto__'] = {w: 2};\nO['__proto__']; // => {w: 2}\nO['w'];         // => 2\n\nvar O = {};\nDict.set(O, 'q', 1);\nO['q'];         // => 1\nDict.set(O, '__proto__', {w: 2});\nO['__proto__']; // => {w: 2}\nO['w'];         // => undefined\n```\nOther methods of `Dict` module are static equialents of `Array.prototype` methods for dictionaries.\n\n[*Examples*](http://goo.gl/xFi1RH):\n```js\nvar dict = {a: 1, b: 2, c: 3};\n\nDict.forEach(dict, console.log, console);\n// => 1, 'a', {a: 1, b: 2, c: 3}\n// => 2, 'b', {a: 1, b: 2, c: 3}\n// => 3, 'c', {a: 1, b: 2, c: 3}\n\nDict.map(dict, function(it){\n  return it * it;\n}); // => {a: 1, b: 4, c: 9}\n\nDict.mapPairs(dict, function(val, key){\n  if(key != 'b')return [key + key, val * val];\n}); // => {aa: 1, cc: 9}\n\nDict.filter(dict, function(it){\n  return it % 2;\n}); // => {a: 1, c: 3}\n\nDict.some(dict, function(it){\n  return it === 2;\n}); // => true\n\nDict.every(dict, function(it){\n  return it === 2;\n}); // => false\n\nDict.find(dict, function(it){\n  return it > 2;\n}); // => 3\nDict.find(dict, function(it){\n  return it > 4;\n}); // => undefined\n\nDict.findKey(dict, function(it){\n  return it > 2;\n}); // => 'c'\nDict.findKey(dict, function(it){\n  return it > 4;\n}); // => undefined\n\nDict.keyOf(dict, 2);    // => 'b'\nDict.keyOf(dict, 4);    // => undefined\n\nDict.includes(dict, 2); // => true\nDict.includes(dict, 4); // => false\n\nDict.reduce(dict, function(memo, it){\n  return memo + it;\n});     // => 6\nDict.reduce(dict, function(memo, it){\n  return memo + it;\n}, ''); // => '123'\n```\n#### Partial application\nModule [`core.function.part`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/core.function.part.js).\n```js\nFunction\n  #part(...args | _) -> fn(...args)\n```\n\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js/core/function\ncore-js(/library)/fn/function/part\ncore-js(/library)/fn/function/virtual/part\ncore-js(/library)/fn/_\n```\n`Function#part` partial apply function without `this` binding. Uses global variable `_` (`core._` for builds without global namespace pollution) as placeholder and not conflict with `Underscore` / `LoDash`.\n\n[*Examples*](http://goo.gl/p9ZJ8K):\n```js\nvar fn1 = log.part(1, 2);\nfn1(3, 4);    // => 1, 2, 3, 4\n\nvar fn2 = log.part(_, 2, _, 4);\nfn2(1, 3);    // => 1, 2, 3, 4\n\nvar fn3 = log.part(1, _, _, 4);\nfn3(2, 3);    // => 1, 2, 3, 4\n\nfn2(1, 3, 5); // => 1, 2, 3, 4, 5\nfn2(1);       // => 1, 2, undefined, 4\n```\n#### Number Iterator\nModule [`core.number.iterator`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/core.number.iterator.js).\n```js\nNumber\n  #@@iterator() -> iterator\n```\n\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/core/number\ncore-js(/library)/fn/number/iterator\ncore-js(/library)/fn/number/virtual/iterator\n```\n[*Examples*](http://goo.gl/o45pCN):\n```js\nfor(var i of 3)console.log(i); // => 0, 1, 2\n\n[...10]; // => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]\n\nArray.from(10, Math.random); // => [0.9817775336559862, 0.02720663254149258, ...]\n\nArray.from(10, function(it){\n  return this + it * it;\n}, .42); // => [0.42, 1.42, 4.42, 9.42, 16.42, 25.42, 36.42, 49.42, 64.42, 81.42]\n```\n#### Escaping strings\nModules [`core.regexp.escape`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/core.regexp.escape.js), [`core.string.escape-html`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/core.string.escape-html.js) and [`core.string.unescape-html`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/core.string.unescape-html.js).\n```js\nRegExp\n  .escape(str) -> str\nString\n  #escapeHTML() -> str\n  #unescapeHTML() -> str\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/core/regexp\ncore-js(/library)/core/string\ncore-js(/library)/fn/regexp/escape\ncore-js(/library)/fn/string/escape-html\ncore-js(/library)/fn/string/unescape-html\ncore-js(/library)/fn/string/virtual/escape-html\ncore-js(/library)/fn/string/virtual/unescape-html\n```\n[*Examples*](http://goo.gl/6bOvsQ):\n```js\nRegExp.escape('Hello, []{}()*+?.\\\\^$|!'); // => 'Hello, \\[\\]\\{\\}\\(\\)\\*\\+\\?\\.\\\\\\^\\$\\|!'\n\n'<script>doSomething();</script>'.escapeHTML(); // => '&lt;script&gt;doSomething();&lt;/script&gt;'\n'&lt;script&gt;doSomething();&lt;/script&gt;'.unescapeHTML(); // => '<script>doSomething();</script>'\n```\n#### delay\nModule [`core.delay`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/core.delay.js). [Promise](#ecmascript-6-promise)-returning delay function, [esdiscuss](https://esdiscuss.org/topic/promise-returning-delay-function).\n```js\ndelay(ms) -> promise\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/core/delay\ncore-js(/library)/fn/delay\n```\n[*Examples*](http://goo.gl/lbucba):\n```js\ndelay(1e3).then(() => console.log('after 1 sec'));\n\n(async () => {\n  await delay(3e3);\n  console.log('after 3 sec');\n\n  while(await delay(3e3))console.log('each 3 sec');\n})();\n```\n#### Helpers for iterators\nModules [`core.is-iterable`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/core.is-iterable.js), [`core.get-iterator`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/core.get-iterator.js), [`core.get-iterator-method`](https://github.com/zloirock/core-js/blob/v2.5.1/modules/core.get-iterator-method.js) - helpers for check iterability / get iterator in the `library` version or, for example, for `arguments` object:\n```js\ncore\n  .isIterable(var) -> bool\n  .getIterator(iterable) -> iterator\n  .getIteratorMethod(var) -> function | undefined\n```\n[*CommonJS entry points:*](#commonjs)\n```js\ncore-js(/library)/fn/is-iterable\ncore-js(/library)/fn/get-iterator\ncore-js(/library)/fn/get-iterator-method\n```\n[*Examples*](http://goo.gl/SXsM6D):\n```js\nvar list = (function(){\n  return arguments;\n})(1, 2, 3);\n\nconsole.log(core.isIterable(list)); // true;\n\nvar iter = core.getIterator(list);\nconsole.log(iter.next().value); // 1\nconsole.log(iter.next().value); // 2\nconsole.log(iter.next().value); // 3\nconsole.log(iter.next().value); // undefined\n\ncore.getIterator({});   // TypeError: [object Object] is not iterable!\n\nvar iterFn = core.getIteratorMethod(list);\nconsole.log(typeof iterFn);     // 'function'\nvar iter = iterFn.call(list);\nconsole.log(iter.next().value); // 1\nconsole.log(iter.next().value); // 2\nconsole.log(iter.next().value); // 3\nconsole.log(iter.next().value); // undefined\n\nconsole.log(core.getIteratorMethod({})); // undefined\n```\n\n## Missing polyfills\n- ES5 `JSON` is missing now only in IE7- and never will it be added to `core-js`, if you need it in these old browsers, many implementations are available, for example, [json3](https://github.com/bestiejs/json3).\n- ES6 `String#normalize` is not a very useful feature, but this polyfill will be very large. If you need it, you can use [unorm](https://github.com/walling/unorm/).\n- ES6 `Proxy` can't be polyfilled, but for Node.js / Chromium with additional flags you can try [harmony-reflect](https://github.com/tvcutsem/harmony-reflect) for adapt old style `Proxy` API to final ES6 version.\n- ES6 logic for `@@isConcatSpreadable` and `@@species` (in most places) can be polyfilled without problems, but it will cause a serious slowdown in popular cases in some engines. It will be polyfilled when it will be implemented in modern engines.\n- ES7 `SIMD`. `core-js` doesn't add polyfill of this feature because of large size and some other reasons. You can use [this polyfill](https://github.com/tc39/ecmascript_simd/blob/master/src/ecmascript_simd.js).\n- `window.fetch` is not a cross-platform feature, in some environments it makes no sense. For this reason, I don't think it should be in `core-js`. Looking at a large number of requests it *may be*  added in the future. Now you can use, for example, [this polyfill](https://github.com/github/fetch).\n- ECMA-402 `Intl` is missed because of size. You can use [this polyfill](https://github.com/andyearnshaw/Intl.js/).\n",
  "readmeFilename": "README.md",
  "repository": {
    "type": "git",
    "url": "git+https://github.com/zloirock/core-js.git"
  },
  "scripts": {
    "grunt": "grunt",
    "lint": "eslint ./",
    "observables-tests": "node tests/observables/adapter && node tests/observables/adapter-library",
    "promises-tests": "promises-aplus-tests tests/promises-aplus/adapter",
    "test": "npm run grunt clean copy && npm run lint && npm run grunt livescript client karma:default && npm run grunt library karma:library && npm run promises-tests && npm run observables-tests && lsc tests/commonjs"
  },
  "version": "2.5.1"
}
