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authorFlorian Dold <florian.dold@gmail.com>2017-08-14 05:01:11 +0200
committerFlorian Dold <florian.dold@gmail.com>2017-08-14 05:02:09 +0200
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+# core-js
+
+[![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)
+#### As advertising: the author is looking for a good job :)
+
+Modular 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.
+
+[*Example*](http://goo.gl/a2xexl):
+```js
+Array.from(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]
+'*'.repeat(10); // => '**********'
+Promise.resolve(32).then(x => console.log(x)); // => 32
+setImmediate(x => console.log(x), 42); // => 42
+```
+
+[*Without global namespace pollution*](http://goo.gl/paOHb0):
+```js
+var core = require('core-js/library'); // With a modular system, otherwise use global `core`
+core.Array.from(new core.Set([1, 2, 3, 2, 1])); // => [1, 2, 3]
+core.String.repeat('*', 10); // => '**********'
+core.Promise.resolve(32).then(x => console.log(x)); // => 32
+core.setImmediate(x => console.log(x), 42); // => 42
+```
+
+### Index
+- [Usage](#usage)
+ - [Basic](#basic)
+ - [CommonJS](#commonjs)
+ - [Custom build](#custom-build-from-the-command-line)
+- [Supported engines](#supported-engines)
+- [Features](#features)
+ - [ECMAScript 5](#ecmascript-5)
+ - [ECMAScript 6](#ecmascript-6)
+ - [ECMAScript 6: Object](#ecmascript-6-object)
+ - [ECMAScript 6: Function](#ecmascript-6-function)
+ - [ECMAScript 6: Array](#ecmascript-6-array)
+ - [ECMAScript 6: String](#ecmascript-6-string)
+ - [ECMAScript 6: RegExp](#ecmascript-6-regexp)
+ - [ECMAScript 6: Number](#ecmascript-6-number)
+ - [ECMAScript 6: Math](#ecmascript-6-math)
+ - [ECMAScript 6: Date](#ecmascript-6-date)
+ - [ECMAScript 6: Promise](#ecmascript-6-promise)
+ - [ECMAScript 6: Symbol](#ecmascript-6-symbol)
+ - [ECMAScript 6: Collections](#ecmascript-6-collections)
+ - [ECMAScript 6: Typed Arrays](#ecmascript-6-typed-arrays)
+ - [ECMAScript 6: Reflect](#ecmascript-6-reflect)
+ - [ECMAScript 7+ proposals](#ecmascript-7-proposals)
+ - [stage 4 proposals](#stage-4-proposals)
+ - [stage 3 proposals](#stage-3-proposals)
+ - [stage 2 proposals](#stage-2-proposals)
+ - [stage 1 proposals](#stage-1-proposals)
+ - [stage 0 proposals](#stage-0-proposals)
+ - [pre-stage 0 proposals](#pre-stage-0-proposals)
+ - [Web standards](#web-standards)
+ - [setTimeout / setInterval](#settimeout--setinterval)
+ - [setImmediate](#setimmediate)
+ - [iterable DOM collections](#iterable-dom-collections)
+ - [Non-standard](#non-standard)
+ - [Object](#object)
+ - [Dict](#dict)
+ - [partial application](#partial-application)
+ - [Number Iterator](#number-iterator)
+ - [escaping strings](#escaping-strings)
+ - [delay](#delay)
+ - [helpers for iterators](#helpers-for-iterators)
+- [Missing polyfills](#missing-polyfills)
+- [Changelog](./CHANGELOG.md)
+
+## Usage
+### Basic
+```
+npm i core-js
+bower install core.js
+```
+
+```js
+// Default
+require('core-js');
+// Without global namespace pollution
+var core = require('core-js/library');
+// Shim only
+require('core-js/shim');
+```
+If you need complete build for browser, use builds from `core-js/client` path:
+
+* [default](https://raw.githack.com/zloirock/core-js/v2.5.0/client/core.min.js): Includes all features, standard and non-standard.
+* [as a library](https://raw.githack.com/zloirock/core-js/v2.5.0/client/library.min.js): Like "default", but does not pollute the global namespace (see [2nd example at the top](#core-js)).
+* [shim only](https://raw.githack.com/zloirock/core-js/v2.5.0/client/shim.min.js): Only includes the standard methods.
+
+Warning: 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.
+
+### CommonJS
+You can require only needed modules.
+
+```js
+require('core-js/fn/set');
+require('core-js/fn/array/from');
+require('core-js/fn/array/find-index');
+Array.from(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]
+[1, 2, NaN, 3, 4].findIndex(isNaN); // => 2
+
+// or, w/o global namespace pollution:
+
+var Set = require('core-js/library/fn/set');
+var from = require('core-js/library/fn/array/from');
+var findIndex = require('core-js/library/fn/array/find-index');
+from(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]
+findIndex([1, 2, NaN, 3, 4], isNaN); // => 2
+```
+Available 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.
+
+##### Caveats when using CommonJS API:
+
+* `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.
+* `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.
+
+#### CommonJS and prototype methods without global namespace pollution
+In 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:
+```js
+import fill from 'core-js/library/fn/array/virtual/fill';
+import findIndex from 'core-js/library/fn/array/virtual/find-index';
+
+Array(10)::fill(0).map((a, b) => b * b)::findIndex(it => it && !(it % 8)); // => 4
+
+// or
+
+import {fill, findIndex} from 'core-js/library/fn/array/virtual';
+
+Array(10)::fill(0).map((a, b) => b * b)::findIndex(it => it && !(it % 8)); // => 4
+
+```
+
+### Custom build (from the command-line)
+```
+npm i core-js && cd node_modules/core-js && npm i
+npm run grunt build:core.dict,es6 -- --blacklist=es6.promise,es6.math --library=on --path=custom uglify
+```
+Where `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.
+
+Available namespaces: for example, `es6.array` contains [ES6 `Array` features](#ecmascript-6-array), `es6` contains all modules whose names start with `es6`.
+
+### Custom build (from external scripts)
+
+[`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`:
+
+```js
+require('core-js-builder')({
+ modules: ['es6', 'core.dict'], // modules / namespaces
+ blacklist: ['es6.reflect'], // blacklist of modules / namespaces, by default - empty list
+ library: false, // flag for build without global namespace pollution, by default - false
+ umd: true // use UMD wrapper for export `core` object, by default - true
+}).then(code => {
+ // ...
+}).catch(error => {
+ // ...
+});
+```
+## Supported engines
+**Tested in:**
+- Chrome 26+
+- Firefox 4+
+- Safari 5+
+- Opera 12+
+- Internet Explorer 6+ (sure, IE8- with ES3 limitations)
+- Edge
+- Android Browser 2.3+
+- iOS Safari 5.1+
+- PhantomJS 1.9 / 2.1
+- NodeJS 0.8+
+
+...and it doesn't mean `core-js` will not work in other engines, they just have not been tested.
+
+## Features:
+[*CommonJS entry points:*](#commonjs)
+```
+core-js(/library) <- all features
+core-js(/library)/shim <- only polyfills
+```
+### ECMAScript 5
+All features moved to the [`es6` namespace](#ecmascript-6), here just a list of features:
+```js
+Object
+ .create(proto | null, descriptors?) -> object
+ .getPrototypeOf(object) -> proto | null
+ .defineProperty(target, key, desc) -> target, cap for ie8-
+ .defineProperties(target, descriptors) -> target, cap for ie8-
+ .getOwnPropertyDescriptor(object, key) -> desc
+ .getOwnPropertyNames(object) -> array
+ .keys(object) -> array
+ .seal(object) -> object, cap for ie8-
+ .freeze(object) -> object, cap for ie8-
+ .preventExtensions(object) -> object, cap for ie8-
+ .isSealed(object) -> bool, cap for ie8-
+ .isFrozen(object) -> bool, cap for ie8-
+ .isExtensible(object) -> bool, cap for ie8-
+Array
+ .isArray(var) -> bool
+ #slice(start?, end?) -> array, fix for ie7-
+ #join(string = ',') -> string, fix for ie7-
+ #indexOf(var, from?) -> int
+ #lastIndexOf(var, from?) -> int
+ #every(fn(val, index, @), that) -> bool
+ #some(fn(val, index, @), that) -> bool
+ #forEach(fn(val, index, @), that) -> void
+ #map(fn(val, index, @), that) -> array
+ #filter(fn(val, index, @), that) -> array
+ #reduce(fn(memo, val, index, @), memo?) -> var
+ #reduceRight(fn(memo, val, index, @), memo?) -> var
+ #sort(fn?) -> @, fixes for some engines
+Function
+ #bind(object, ...args) -> boundFn(...args)
+String
+ #split(separator, limit) -> array
+ #trim() -> str
+RegExp
+ #toString() -> str
+Number
+ #toFixed(digits) -> string
+ #toPrecision(precision) -> string
+parseInt(str, radix) -> int
+parseFloat(str) -> num
+Date
+ .now() -> int
+ #toISOString() -> string
+ #toJSON() -> string
+```
+[*CommonJS entry points:*](#commonjs)
+```
+core-js(/library)/es5
+```
+
+### ECMAScript 6
+[*CommonJS entry points:*](#commonjs)
+```
+core-js(/library)/es6
+```
+#### ECMAScript 6: Object
+Modules [`es6.object.assign`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.object.assign.js), [`es6.object.is`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.object.is.js), [`es6.object.set-prototype-of`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.object.set-prototype-of.js) and [`es6.object.to-string`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.object.to-string.js).
+
+In ES6 most `Object` static methods should work with primitives. Modules [`es6.object.freeze`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.object.freeze.js), [`es6.object.seal`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.object.seal.js), [`es6.object.prevent-extensions`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.object.prevent-extensions.js), [`es6.object.is-frozen`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.object.is-frozen.js), [`es6.object.is-sealed`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.object.is-sealed.js), [`es6.object.is-extensible`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.object.is-extensible.js), [`es6.object.get-own-property-descriptor`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.object.get-own-property-descriptor.js), [`es6.object.get-prototype-of`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.object.get-prototype-of.js), [`es6.object.keys`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.object.keys.js) and [`es6.object.get-own-property-names`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.object.get-own-property-names.js).
+
+Just ES5 features: [`es6.object.create`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.object.create.js), [`es6.object.define-property`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.object.define-property.js) and [`es6.object.define-properties`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.object.es6.object.define-properties.js).
+```js
+Object
+ .assign(target, ...src) -> target
+ .is(a, b) -> bool
+ .setPrototypeOf(target, proto | null) -> target (required __proto__ - IE11+)
+ .create(object | null, descriptors?) -> object
+ .getPrototypeOf(var) -> object | null
+ .defineProperty(object, key, desc) -> target
+ .defineProperties(object, descriptors) -> target
+ .getOwnPropertyDescriptor(var, key) -> desc | undefined
+ .keys(var) -> array
+ .getOwnPropertyNames(var) -> array
+ .freeze(var) -> var
+ .seal(var) -> var
+ .preventExtensions(var) -> var
+ .isFrozen(var) -> bool
+ .isSealed(var) -> bool
+ .isExtensible(var) -> bool
+ #toString() -> string, ES6 fix: @@toStringTag support
+```
+[*CommonJS entry points:*](#commonjs)
+```
+core-js(/library)/es6/object
+core-js(/library)/fn/object/assign
+core-js(/library)/fn/object/is
+core-js(/library)/fn/object/set-prototype-of
+core-js(/library)/fn/object/get-prototype-of
+core-js(/library)/fn/object/create
+core-js(/library)/fn/object/define-property
+core-js(/library)/fn/object/define-properties
+core-js(/library)/fn/object/get-own-property-descriptor
+core-js(/library)/fn/object/keys
+core-js(/library)/fn/object/get-own-property-names
+core-js(/library)/fn/object/freeze
+core-js(/library)/fn/object/seal
+core-js(/library)/fn/object/prevent-extensions
+core-js(/library)/fn/object/is-frozen
+core-js(/library)/fn/object/is-sealed
+core-js(/library)/fn/object/is-extensible
+core-js/fn/object/to-string
+```
+[*Examples*](http://goo.gl/ywdwPz):
+```js
+var foo = {q: 1, w: 2}
+ , bar = {e: 3, r: 4}
+ , baz = {t: 5, y: 6};
+Object.assign(foo, bar, baz); // => foo = {q: 1, w: 2, e: 3, r: 4, t: 5, y: 6}
+
+Object.is(NaN, NaN); // => true
+Object.is(0, -0); // => false
+Object.is(42, 42); // => true
+Object.is(42, '42'); // => false
+
+function Parent(){}
+function Child(){}
+Object.setPrototypeOf(Child.prototype, Parent.prototype);
+new Child instanceof Child; // => true
+new Child instanceof Parent; // => true
+
+var O = {};
+O[Symbol.toStringTag] = 'Foo';
+'' + O; // => '[object Foo]'
+
+Object.keys('qwe'); // => ['0', '1', '2']
+Object.getPrototypeOf('qwe') === String.prototype; // => true
+```
+#### ECMAScript 6: Function
+Modules [`es6.function.name`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.function.name.js), [`es6.function.has-instance`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.function.has-instance.js). Just ES5: [`es6.function.bind`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.function.bind.js).
+```js
+Function
+ #bind(object, ...args) -> boundFn(...args)
+ #name -> string (IE9+)
+ #@@hasInstance(var) -> bool
+```
+[*CommonJS entry points:*](#commonjs)
+```
+core-js/es6/function
+core-js/fn/function/name
+core-js/fn/function/has-instance
+core-js/fn/function/bind
+core-js/fn/function/virtual/bind
+```
+[*Example*](http://goo.gl/zqu3Wp):
+```js
+(function foo(){}).name // => 'foo'
+
+console.log.bind(console, 42)(43); // => 42 43
+```
+#### ECMAScript 6: Array
+Modules [`es6.array.from`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.from.js), [`es6.array.of`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.of.js), [`es6.array.copy-within`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.copy-within.js), [`es6.array.fill`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.fill.js), [`es6.array.find`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.find.js), [`es6.array.find-index`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.find-index.js), [`es6.array.iterator`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.iterator.js). ES5 features with fixes: [`es6.array.is-array`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.is-array.js), [`es6.array.slice`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.slice.js), [`es6.array.join`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.join.js), [`es6.array.index-of`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.index-of.js), [`es6.array.last-index-of`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.last-index-of.js), [`es6.array.every`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.every.js), [`es6.array.some`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.some.js), [`es6.array.for-each`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.for-each.js), [`es6.array.map`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.map.js), [`es6.array.filter`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.filter.js), [`es6.array.reduce`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.reduce.js), [`es6.array.reduce-right`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.reduce-right.js), [`es6.array.sort`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.array.sort.js).
+```js
+Array
+ .from(iterable | array-like, mapFn(val, index)?, that) -> array
+ .of(...args) -> array
+ .isArray(var) -> bool
+ #copyWithin(target = 0, start = 0, end = @length) -> @
+ #fill(val, start = 0, end = @length) -> @
+ #find(fn(val, index, @), that) -> val
+ #findIndex(fn(val, index, @), that) -> index | -1
+ #values() -> iterator
+ #keys() -> iterator
+ #entries() -> iterator
+ #join(string = ',') -> string, fix for ie7-
+ #slice(start?, end?) -> array, fix for ie7-
+ #indexOf(var, from?) -> index | -1
+ #lastIndexOf(var, from?) -> index | -1
+ #every(fn(val, index, @), that) -> bool
+ #some(fn(val, index, @), that) -> bool
+ #forEach(fn(val, index, @), that) -> void
+ #map(fn(val, index, @), that) -> array
+ #filter(fn(val, index, @), that) -> array
+ #reduce(fn(memo, val, index, @), memo?) -> var
+ #reduceRight(fn(memo, val, index, @), memo?) -> var
+ #sort(fn?) -> @, invalid arguments fix
+ #@@iterator() -> iterator (values)
+ #@@unscopables -> object (cap)
+Arguments
+ #@@iterator() -> iterator (values, available only in core-js methods)
+```
+[*CommonJS entry points:*](#commonjs)
+```
+core-js(/library)/es6/array
+core-js(/library)/fn/array/from
+core-js(/library)/fn/array/of
+core-js(/library)/fn/array/is-array
+core-js(/library)/fn/array/iterator
+core-js(/library)/fn/array/copy-within
+core-js(/library)/fn/array/fill
+core-js(/library)/fn/array/find
+core-js(/library)/fn/array/find-index
+core-js(/library)/fn/array/values
+core-js(/library)/fn/array/keys
+core-js(/library)/fn/array/entries
+core-js(/library)/fn/array/slice
+core-js(/library)/fn/array/join
+core-js(/library)/fn/array/index-of
+core-js(/library)/fn/array/last-index-of
+core-js(/library)/fn/array/every
+core-js(/library)/fn/array/some
+core-js(/library)/fn/array/for-each
+core-js(/library)/fn/array/map
+core-js(/library)/fn/array/filter
+core-js(/library)/fn/array/reduce
+core-js(/library)/fn/array/reduce-right
+core-js(/library)/fn/array/sort
+core-js(/library)/fn/array/virtual/iterator
+core-js(/library)/fn/array/virtual/copy-within
+core-js(/library)/fn/array/virtual/fill
+core-js(/library)/fn/array/virtual/find
+core-js(/library)/fn/array/virtual/find-index
+core-js(/library)/fn/array/virtual/values
+core-js(/library)/fn/array/virtual/keys
+core-js(/library)/fn/array/virtual/entries
+core-js(/library)/fn/array/virtual/slice
+core-js(/library)/fn/array/virtual/join
+core-js(/library)/fn/array/virtual/index-of
+core-js(/library)/fn/array/virtual/last-index-of
+core-js(/library)/fn/array/virtual/every
+core-js(/library)/fn/array/virtual/some
+core-js(/library)/fn/array/virtual/for-each
+core-js(/library)/fn/array/virtual/map
+core-js(/library)/fn/array/virtual/filter
+core-js(/library)/fn/array/virtual/reduce
+core-js(/library)/fn/array/virtual/reduce-right
+core-js(/library)/fn/array/virtual/sort
+```
+[*Examples*](http://goo.gl/oaUFUf):
+```js
+Array.from(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]
+Array.from({0: 1, 1: 2, 2: 3, length: 3}); // => [1, 2, 3]
+Array.from('123', Number); // => [1, 2, 3]
+Array.from('123', function(it){
+ return it * it;
+}); // => [1, 4, 9]
+
+Array.of(1); // => [1]
+Array.of(1, 2, 3); // => [1, 2, 3]
+
+var array = ['a', 'b', 'c'];
+
+for(var val of array)console.log(val); // => 'a', 'b', 'c'
+for(var val of array.values())console.log(val); // => 'a', 'b', 'c'
+for(var key of array.keys())console.log(key); // => 0, 1, 2
+for(var [key, val] of array.entries()){
+ console.log(key); // => 0, 1, 2
+ console.log(val); // => 'a', 'b', 'c'
+}
+
+function isOdd(val){
+ return val % 2;
+}
+[4, 8, 15, 16, 23, 42].find(isOdd); // => 15
+[4, 8, 15, 16, 23, 42].findIndex(isOdd); // => 2
+[4, 8, 15, 16, 23, 42].find(isNaN); // => undefined
+[4, 8, 15, 16, 23, 42].findIndex(isNaN); // => -1
+
+Array(5).fill(42); // => [42, 42, 42, 42, 42]
+
+[1, 2, 3, 4, 5].copyWithin(0, 3); // => [4, 5, 3, 4, 5]
+```
+#### ECMAScript 6: String
+Modules [`es6.string.from-code-point`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.from-code-point.js), [`es6.string.raw`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.raw.js), [`es6.string.iterator`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.iterator.js), [`es6.string.code-point-at`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.code-point-at.js), [`es6.string.ends-with`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.ends-with.js), [`es6.string.includes`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.includes.js), [`es6.string.repeat`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.repeat.js), [`es6.string.starts-with`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.starts-with.js) and [`es6.string.trim`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.trim.js).
+
+Annex B HTML methods. Ugly, but it's also the part of the spec. Modules [`es6.string.anchor`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.anchor.js), [`es6.string.big`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.big.js), [`es6.string.blink`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.blink.js), [`es6.string.bold`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.bold.js), [`es6.string.fixed`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.fixed.js), [`es6.string.fontcolor`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.fontcolor.js), [`es6.string.fontsize`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.fontsize.js), [`es6.string.italics`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.italics.js), [`es6.string.link`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.link.js), [`es6.string.small`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.small.js), [`es6.string.strike`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.strike.js), [`es6.string.sub`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.sub.js) and [`es6.string.sup`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.string.sup.js).
+```js
+String
+ .fromCodePoint(...codePoints) -> str
+ .raw({raw}, ...substitutions) -> str
+ #includes(str, from?) -> bool
+ #startsWith(str, from?) -> bool
+ #endsWith(str, from?) -> bool
+ #repeat(num) -> str
+ #codePointAt(pos) -> uint
+ #trim() -> str, ES6 fix
+ #anchor(name) -> str
+ #big() -> str
+ #blink() -> str
+ #bold() -> str
+ #fixed() -> str
+ #fontcolor(color) -> str
+ #fontsize(size) -> str
+ #italics() -> str
+ #link(url) -> str
+ #small() -> str
+ #strike() -> str
+ #sub() -> str
+ #sup() -> str
+ #@@iterator() -> iterator (code points)
+```
+[*CommonJS entry points:*](#commonjs)
+```
+core-js(/library)/es6/string
+core-js(/library)/fn/string/from-code-point
+core-js(/library)/fn/string/raw
+core-js(/library)/fn/string/includes
+core-js(/library)/fn/string/starts-with
+core-js(/library)/fn/string/ends-with
+core-js(/library)/fn/string/repeat
+core-js(/library)/fn/string/code-point-at
+core-js(/library)/fn/string/trim
+core-js(/library)/fn/string/anchor
+core-js(/library)/fn/string/big
+core-js(/library)/fn/string/blink
+core-js(/library)/fn/string/bold
+core-js(/library)/fn/string/fixed
+core-js(/library)/fn/string/fontcolor
+core-js(/library)/fn/string/fontsize
+core-js(/library)/fn/string/italics
+core-js(/library)/fn/string/link
+core-js(/library)/fn/string/small
+core-js(/library)/fn/string/strike
+core-js(/library)/fn/string/sub
+core-js(/library)/fn/string/sup
+core-js(/library)/fn/string/iterator
+core-js(/library)/fn/string/virtual/includes
+core-js(/library)/fn/string/virtual/starts-with
+core-js(/library)/fn/string/virtual/ends-with
+core-js(/library)/fn/string/virtual/repeat
+core-js(/library)/fn/string/virtual/code-point-at
+core-js(/library)/fn/string/virtual/trim
+core-js(/library)/fn/string/virtual/anchor
+core-js(/library)/fn/string/virtual/big
+core-js(/library)/fn/string/virtual/blink
+core-js(/library)/fn/string/virtual/bold
+core-js(/library)/fn/string/virtual/fixed
+core-js(/library)/fn/string/virtual/fontcolor
+core-js(/library)/fn/string/virtual/fontsize
+core-js(/library)/fn/string/virtual/italics
+core-js(/library)/fn/string/virtual/link
+core-js(/library)/fn/string/virtual/small
+core-js(/library)/fn/string/virtual/strike
+core-js(/library)/fn/string/virtual/sub
+core-js(/library)/fn/string/virtual/sup
+core-js(/library)/fn/string/virtual/iterator
+```
+[*Examples*](http://goo.gl/3UaQ93):
+```js
+for(var val of 'a𠮷b'){
+ console.log(val); // => 'a', '𠮷', 'b'
+}
+
+'foobarbaz'.includes('bar'); // => true
+'foobarbaz'.includes('bar', 4); // => false
+'foobarbaz'.startsWith('foo'); // => true
+'foobarbaz'.startsWith('bar', 3); // => true
+'foobarbaz'.endsWith('baz'); // => true
+'foobarbaz'.endsWith('bar', 6); // => true
+
+'string'.repeat(3); // => 'stringstringstring'
+
+'𠮷'.codePointAt(0); // => 134071
+String.fromCodePoint(97, 134071, 98); // => 'a𠮷b'
+
+var name = 'Bob';
+String.raw`Hi\n${name}!`; // => 'Hi\\nBob!' (ES6 template string syntax)
+String.raw({raw: 'test'}, 0, 1, 2); // => 't0e1s2t'
+
+'foo'.bold(); // => '<b>foo</b>'
+'bar'.anchor('a"b'); // => '<a name="a&quot;b">bar</a>'
+'baz'.link('http://example.com'); // => '<a href="http://example.com">baz</a>'
+```
+#### ECMAScript 6: RegExp
+Modules [`es6.regexp.constructor`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.regexp.constructor.js) and [`es6.regexp.flags`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.regexp.flags.js).
+
+Support well-known [symbols](#ecmascript-6-symbol) `@@match`, `@@replace`, `@@search` and `@@split`, modules [`es6.regexp.match`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.regexp.match.js), [`es6.regexp.replace`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.regexp.replace.js), [`es6.regexp.search`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.regexp.search.js) and [`es6.regexp.split`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.regexp.split.js).
+```
+[new] RegExp(pattern, flags?) -> regexp, ES6 fix: can alter flags (IE9+)
+ #flags -> str (IE9+)
+ #toString() -> str, ES6 fixes
+ #@@match(str) -> array | null
+ #@@replace(str, replacer) -> string
+ #@@search(str) -> index
+ #@@split(str, limit) -> array
+String
+ #match(tpl) -> var, ES6 fix for support @@match
+ #replace(tpl, replacer) -> var, ES6 fix for support @@replace
+ #search(tpl) -> var, ES6 fix for support @@search
+ #split(tpl, limit) -> var, ES6 fix for support @@split, some fixes for old engines
+```
+[*CommonJS entry points:*](#commonjs)
+```
+core-js/es6/regexp
+core-js/fn/regexp/constructor
+core-js(/library)/fn/regexp/flags
+core-js/fn/regexp/to-string
+core-js/fn/regexp/match
+core-js/fn/regexp/replace
+core-js/fn/regexp/search
+core-js/fn/regexp/split
+```
+[*Examples*](http://goo.gl/PiJxBD):
+```js
+RegExp(/./g, 'm'); // => /./m
+
+/foo/.flags; // => ''
+/foo/gim.flags; // => 'gim'
+
+'foo'.match({[Symbol.match]: _ => 1}); // => 1
+'foo'.replace({[Symbol.replace]: _ => 2}); // => 2
+'foo'.search({[Symbol.search]: _ => 3}); // => 3
+'foo'.split({[Symbol.split]: _ => 4}); // => 4
+
+RegExp.prototype.toString.call({source: 'foo', flags: 'bar'}); // => '/foo/bar'
+```
+#### ECMAScript 6: Number
+Module [`es6.number.constructor`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.number.constructor.js). `Number` constructor support binary and octal literals, [*example*](http://goo.gl/jRd6b3):
+```js
+Number('0b1010101'); // => 85
+Number('0o7654321'); // => 2054353
+```
+Modules [`es6.number.epsilon`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.number.epsilon.js), [`es6.number.is-finite`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.number.is-finite.js), [`es6.number.is-integer`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.number.is-integer.js), [`es6.number.is-nan`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.number.is-nan.js), [`es6.number.is-safe-integer`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.number.is-safe-integer.js), [`es6.number.max-safe-integer`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.number.max-safe-integer.js), [`es6.number.min-safe-integer`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.number.min-safe-integer.js), [`es6.number.parse-float`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.number.parse-float.js), [`es6.number.parse-int`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.number.parse-int.js), [`es6.number.to-fixed`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.number.to-fixed.js), [`es6.number.to-precision`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.number.to-precision.js), [`es6.parse-int`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.parse-int.js), [`es6.parse-float`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.parse-float.js).
+```js
+[new] Number(var) -> number | number object
+ .isFinite(num) -> bool
+ .isNaN(num) -> bool
+ .isInteger(num) -> bool
+ .isSafeInteger(num) -> bool
+ .parseFloat(str) -> num
+ .parseInt(str) -> int
+ .EPSILON -> num
+ .MAX_SAFE_INTEGER -> int
+ .MIN_SAFE_INTEGER -> int
+ #toFixed(digits) -> string, fixes
+ #toPrecision(precision) -> string, fixes
+parseFloat(str) -> num, fixes
+parseInt(str) -> int, fixes
+```
+[*CommonJS entry points:*](#commonjs)
+```
+core-js(/library)/es6/number
+core-js/es6/number/constructor
+core-js(/library)/fn/number/is-finite
+core-js(/library)/fn/number/is-nan
+core-js(/library)/fn/number/is-integer
+core-js(/library)/fn/number/is-safe-integer
+core-js(/library)/fn/number/parse-float
+core-js(/library)/fn/number/parse-int
+core-js(/library)/fn/number/epsilon
+core-js(/library)/fn/number/max-safe-integer
+core-js(/library)/fn/number/min-safe-integer
+core-js(/library)/fn/number/to-fixed
+core-js(/library)/fn/number/to-precision
+core-js(/library)/fn/parse-float
+core-js(/library)/fn/parse-int
+```
+#### ECMAScript 6: Math
+Modules [`es6.math.acosh`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.math.acosh.js), [`es6.math.asinh`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.math.asinh.js), [`es6.math.atanh`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.math.atanh.js), [`es6.math.cbrt`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.math.cbrt.js), [`es6.math.clz32`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.math.clz32.js), [`es6.math.cosh`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.math.cosh.js), [`es6.math.expm1`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.math.expm1.js), [`es6.math.fround`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.math.fround.js), [`es6.math.hypot`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.math.hypot.js), [`es6.math.imul`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.math.imul.js), [`es6.math.log10`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.math.log10.js), [`es6.math.log1p`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.math.log1p.js), [`es6.math.log2`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.math.log2.js), [`es6.math.sign`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.math.sign.js), [`es6.math.sinh`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.math.sinh.js), [`es6.math.tanh`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.math.tanh.js), [`es6.math.trunc`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.math.trunc.js).
+```js
+Math
+ .acosh(num) -> num
+ .asinh(num) -> num
+ .atanh(num) -> num
+ .cbrt(num) -> num
+ .clz32(num) -> uint
+ .cosh(num) -> num
+ .expm1(num) -> num
+ .fround(num) -> num
+ .hypot(...args) -> num
+ .imul(num, num) -> int
+ .log1p(num) -> num
+ .log10(num) -> num
+ .log2(num) -> num
+ .sign(num) -> 1 | -1 | 0 | -0 | NaN
+ .sinh(num) -> num
+ .tanh(num) -> num
+ .trunc(num) -> num
+```
+[*CommonJS entry points:*](#commonjs)
+```
+core-js(/library)/es6/math
+core-js(/library)/fn/math/acosh
+core-js(/library)/fn/math/asinh
+core-js(/library)/fn/math/atanh
+core-js(/library)/fn/math/cbrt
+core-js(/library)/fn/math/clz32
+core-js(/library)/fn/math/cosh
+core-js(/library)/fn/math/expm1
+core-js(/library)/fn/math/fround
+core-js(/library)/fn/math/hypot
+core-js(/library)/fn/math/imul
+core-js(/library)/fn/math/log1p
+core-js(/library)/fn/math/log10
+core-js(/library)/fn/math/log2
+core-js(/library)/fn/math/sign
+core-js(/library)/fn/math/sinh
+core-js(/library)/fn/math/tanh
+core-js(/library)/fn/math/trunc
+```
+#### ECMAScript 6: Date
+Modules [`es6.date.to-string`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.date.to-string.js), ES5 features with fixes: [`es6.date.now`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.date.now.js), [`es6.date.to-iso-string`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.date.to-iso-string.js), [`es6.date.to-json`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.date.to-json.js) and [`es6.date.to-primitive`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.date.to-primitive.js).
+```js
+Date
+ .now() -> int
+ #toISOString() -> string
+ #toJSON() -> string
+ #toString() -> string
+ #@@toPrimitive(hint) -> primitive
+```
+[*CommonJS entry points:*](#commonjs)
+```
+core-js/es6/date
+core-js/fn/date/to-string
+core-js(/library)/fn/date/now
+core-js(/library)/fn/date/to-iso-string
+core-js(/library)/fn/date/to-json
+core-js(/library)/fn/date/to-primitive
+```
+[*Example*](http://goo.gl/haeHLR):
+```js
+new Date(NaN).toString(); // => 'Invalid Date'
+```
+
+#### ECMAScript 6: Promise
+Module [`es6.promise`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.promise.js).
+```js
+new Promise(executor(resolve(var), reject(var))) -> promise
+ #then(resolved(var), rejected(var)) -> promise
+ #catch(rejected(var)) -> promise
+ .resolve(promise | var) -> promise
+ .reject(var) -> promise
+ .all(iterable) -> promise
+ .race(iterable) -> promise
+```
+[*CommonJS entry points:*](#commonjs)
+```
+core-js(/library)/es6/promise
+core-js(/library)/fn/promise
+```
+Basic [*example*](http://goo.gl/vGrtUC):
+```js
+function sleepRandom(time){
+ return new Promise(function(resolve, reject){
+ setTimeout(resolve, time * 1e3, 0 | Math.random() * 1e3);
+ });
+}
+
+console.log('Run'); // => Run
+sleepRandom(5).then(function(result){
+ console.log(result); // => 869, after 5 sec.
+ return sleepRandom(10);
+}).then(function(result){
+ console.log(result); // => 202, after 10 sec.
+}).then(function(){
+ console.log('immediately after'); // => immediately after
+ throw Error('Irror!');
+}).then(function(){
+ console.log('will not be displayed');
+}).catch(x => console.log(x)); // => => Error: Irror!
+```
+`Promise.resolve` and `Promise.reject` [*example*](http://goo.gl/vr8TN3):
+```js
+Promise.resolve(42).then(x => console.log(x)); // => 42
+Promise.reject(42).catch(x => console.log(x)); // => 42
+
+Promise.resolve($.getJSON('/data.json')); // => ES6 promise
+```
+`Promise.all` [*example*](http://goo.gl/RdoDBZ):
+```js
+Promise.all([
+ 'foo',
+ sleepRandom(5),
+ sleepRandom(15),
+ sleepRandom(10) // after 15 sec:
+]).then(x => console.log(x)); // => ['foo', 956, 85, 382]
+```
+`Promise.race` [*example*](http://goo.gl/L8ovkJ):
+```js
+function timeLimit(promise, time){
+ return Promise.race([promise, new Promise(function(resolve, reject){
+ setTimeout(reject, time * 1e3, Error('Await > ' + time + ' sec'));
+ })]);
+}
+
+timeLimit(sleepRandom(5), 10).then(x => console.log(x)); // => 853, after 5 sec.
+timeLimit(sleepRandom(15), 10).catch(x => console.log(x)); // Error: Await > 10 sec
+```
+ECMAScript 7 [async functions](https://tc39.github.io/ecmascript-asyncawait) [example](http://goo.gl/wnQS4j):
+```js
+var delay = time => new Promise(resolve => setTimeout(resolve, time))
+
+async function sleepRandom(time){
+ await delay(time * 1e3);
+ return 0 | Math.random() * 1e3;
+};
+async function sleepError(time, msg){
+ await delay(time * 1e3);
+ throw Error(msg);
+};
+
+(async () => {
+ try {
+ console.log('Run'); // => Run
+ console.log(await sleepRandom(5)); // => 936, after 5 sec.
+ var [a, b, c] = await Promise.all([
+ sleepRandom(5),
+ sleepRandom(15),
+ sleepRandom(10)
+ ]);
+ console.log(a, b, c); // => 210 445 71, after 15 sec.
+ await sleepError(5, 'Irror!');
+ console.log('Will not be displayed');
+ } catch(e){
+ console.log(e); // => Error: 'Irror!', after 5 sec.
+ }
+})();
+```
+
+##### Unhandled rejection tracking
+
+In 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):
+```js
+process.on('unhandledRejection', (reason, promise) => console.log('unhandled', reason, promise));
+process.on('rejectionHandled', (promise) => console.log('handled', promise));
+
+var p = Promise.reject(42);
+// unhandled 42 [object Promise]
+
+setTimeout(() => p.catch(_ => _), 1e3);
+// handled [object Promise]
+```
+In 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):
+```js
+window.onunhandledrejection = e => console.log('unhandled', e.reason, e.promise);
+window.onrejectionhandled = e => console.log('handled', e.reason, e.promise);
+
+var p = Promise.reject(42);
+// unhandled 42 [object Promise]
+
+setTimeout(() => p.catch(_ => _), 1e3);
+// handled 42 [object Promise]
+```
+
+#### ECMAScript 6: Symbol
+Module [`es6.symbol`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.symbol.js).
+```js
+Symbol(description?) -> symbol
+ .hasInstance -> @@hasInstance
+ .isConcatSpreadable -> @@isConcatSpreadable
+ .iterator -> @@iterator
+ .match -> @@match
+ .replace -> @@replace
+ .search -> @@search
+ .species -> @@species
+ .split -> @@split
+ .toPrimitive -> @@toPrimitive
+ .toStringTag -> @@toStringTag
+ .unscopables -> @@unscopables
+ .for(key) -> symbol
+ .keyFor(symbol) -> key
+ .useSimple() -> void
+ .useSetter() -> void
+Object
+ .getOwnPropertySymbols(object) -> array
+```
+Also wrapped some methods for correct work with `Symbol` polyfill.
+```js
+Object
+ .create(proto | null, descriptors?) -> object
+ .defineProperty(target, key, desc) -> target
+ .defineProperties(target, descriptors) -> target
+ .getOwnPropertyDescriptor(var, key) -> desc | undefined
+ .getOwnPropertyNames(var) -> array
+ #propertyIsEnumerable(key) -> bool
+JSON
+ .stringify(target, replacer?, space?) -> string | undefined
+```
+[*CommonJS entry points:*](#commonjs)
+```
+core-js(/library)/es6/symbol
+core-js(/library)/fn/symbol
+core-js(/library)/fn/symbol/has-instance
+core-js(/library)/fn/symbol/is-concat-spreadable
+core-js(/library)/fn/symbol/iterator
+core-js(/library)/fn/symbol/match
+core-js(/library)/fn/symbol/replace
+core-js(/library)/fn/symbol/search
+core-js(/library)/fn/symbol/species
+core-js(/library)/fn/symbol/split
+core-js(/library)/fn/symbol/to-primitive
+core-js(/library)/fn/symbol/to-string-tag
+core-js(/library)/fn/symbol/unscopables
+core-js(/library)/fn/symbol/for
+core-js(/library)/fn/symbol/key-for
+```
+[*Basic example*](http://goo.gl/BbvWFc):
+```js
+var Person = (function(){
+ var NAME = Symbol('name');
+ function Person(name){
+ this[NAME] = name;
+ }
+ Person.prototype.getName = function(){
+ return this[NAME];
+ };
+ return Person;
+})();
+
+var person = new Person('Vasya');
+console.log(person.getName()); // => 'Vasya'
+console.log(person['name']); // => undefined
+console.log(person[Symbol('name')]); // => undefined, symbols are uniq
+for(var key in person)console.log(key); // => only 'getName', symbols are not enumerable
+```
+`Symbol.for` & `Symbol.keyFor` [*example*](http://goo.gl/0pdJjX):
+```js
+var symbol = Symbol.for('key');
+symbol === Symbol.for('key'); // true
+Symbol.keyFor(symbol); // 'key'
+```
+[*Example*](http://goo.gl/mKVOQJ) with methods for getting own object keys:
+```js
+var O = {a: 1};
+Object.defineProperty(O, 'b', {value: 2});
+O[Symbol('c')] = 3;
+Object.keys(O); // => ['a']
+Object.getOwnPropertyNames(O); // => ['a', 'b']
+Object.getOwnPropertySymbols(O); // => [Symbol(c)]
+Reflect.ownKeys(O); // => ['a', 'b', Symbol(c)]
+```
+##### Caveats when using `Symbol` polyfill:
+
+* We can't add new primitive type, `Symbol` returns object.
+* `Symbol.for` and `Symbol.keyFor` can't be shimmed cross-realm.
+* 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`.
+
+You can disable defining setters in `Object.prototype`. [Example](http://goo.gl/N5UD7J):
+```js
+Symbol.useSimple();
+var s1 = Symbol('s1')
+ , o1 = {};
+o1[s1] = true;
+for(var key in o1)console.log(key); // => 'Symbol(s1)_t.qamkg9f3q', w/o native Symbol
+
+Symbol.useSetter();
+var s2 = Symbol('s2')
+ , o2 = {};
+o2[s2] = true;
+for(var key in o2)console.log(key); // nothing
+```
+* 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.
+* Some problems possible with environment exotic objects (for example, IE `localStorage`).
+
+#### ECMAScript 6: Collections
+`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).
+#### Map
+Module [`es6.map`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.map.js).
+```js
+new Map(iterable (entries) ?) -> map
+ #clear() -> void
+ #delete(key) -> bool
+ #forEach(fn(val, key, @), that) -> void
+ #get(key) -> val
+ #has(key) -> bool
+ #set(key, val) -> @
+ #size -> uint
+ #values() -> iterator
+ #keys() -> iterator
+ #entries() -> iterator
+ #@@iterator() -> iterator (entries)
+```
+[*CommonJS entry points:*](#commonjs)
+```
+core-js(/library)/es6/map
+core-js(/library)/fn/map
+```
+[*Examples*](http://goo.gl/GWR7NI):
+```js
+var a = [1];
+
+var map = new Map([['a', 1], [42, 2]]);
+map.set(a, 3).set(true, 4);
+
+console.log(map.size); // => 4
+console.log(map.has(a)); // => true
+console.log(map.has([1])); // => false
+console.log(map.get(a)); // => 3
+map.forEach(function(val, key){
+ console.log(val); // => 1, 2, 3, 4
+ console.log(key); // => 'a', 42, [1], true
+});
+map.delete(a);
+console.log(map.size); // => 3
+console.log(map.get(a)); // => undefined
+console.log(Array.from(map)); // => [['a', 1], [42, 2], [true, 4]]
+
+var map = new Map([['a', 1], ['b', 2], ['c', 3]]);
+
+for(var [key, val] of map){
+ console.log(key); // => 'a', 'b', 'c'
+ console.log(val); // => 1, 2, 3
+}
+for(var val of map.values())console.log(val); // => 1, 2, 3
+for(var key of map.keys())console.log(key); // => 'a', 'b', 'c'
+for(var [key, val] of map.entries()){
+ console.log(key); // => 'a', 'b', 'c'
+ console.log(val); // => 1, 2, 3
+}
+```
+#### Set
+Module [`es6.set`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.set.js).
+```js
+new Set(iterable?) -> set
+ #add(key) -> @
+ #clear() -> void
+ #delete(key) -> bool
+ #forEach(fn(el, el, @), that) -> void
+ #has(key) -> bool
+ #size -> uint
+ #values() -> iterator
+ #keys() -> iterator
+ #entries() -> iterator
+ #@@iterator() -> iterator (values)
+```
+[*CommonJS entry points:*](#commonjs)
+```
+core-js(/library)/es6/set
+core-js(/library)/fn/set
+```
+[*Examples*](http://goo.gl/bmhLwg):
+```js
+var set = new Set(['a', 'b', 'a', 'c']);
+set.add('d').add('b').add('e');
+console.log(set.size); // => 5
+console.log(set.has('b')); // => true
+set.forEach(function(it){
+ console.log(it); // => 'a', 'b', 'c', 'd', 'e'
+});
+set.delete('b');
+console.log(set.size); // => 4
+console.log(set.has('b')); // => false
+console.log(Array.from(set)); // => ['a', 'c', 'd', 'e']
+
+var set = new Set([1, 2, 3, 2, 1]);
+
+for(var val of set)console.log(val); // => 1, 2, 3
+for(var val of set.values())console.log(val); // => 1, 2, 3
+for(var key of set.keys())console.log(key); // => 1, 2, 3
+for(var [key, val] of set.entries()){
+ console.log(key); // => 1, 2, 3
+ console.log(val); // => 1, 2, 3
+}
+```
+#### WeakMap
+Module [`es6.weak-map`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.weak-map.js).
+```js
+new WeakMap(iterable (entries) ?) -> weakmap
+ #delete(key) -> bool
+ #get(key) -> val
+ #has(key) -> bool
+ #set(key, val) -> @
+```
+[*CommonJS entry points:*](#commonjs)
+```
+core-js(/library)/es6/weak-map
+core-js(/library)/fn/weak-map
+```
+[*Examples*](http://goo.gl/SILXyw):
+```js
+var a = [1]
+ , b = [2]
+ , c = [3];
+
+var wmap = new WeakMap([[a, 1], [b, 2]]);
+wmap.set(c, 3).set(b, 4);
+console.log(wmap.has(a)); // => true
+console.log(wmap.has([1])); // => false
+console.log(wmap.get(a)); // => 1
+wmap.delete(a);
+console.log(wmap.get(a)); // => undefined
+
+// Private properties store:
+var Person = (function(){
+ var names = new WeakMap;
+ function Person(name){
+ names.set(this, name);
+ }
+ Person.prototype.getName = function(){
+ return names.get(this);
+ };
+ return Person;
+})();
+
+var person = new Person('Vasya');
+console.log(person.getName()); // => 'Vasya'
+for(var key in person)console.log(key); // => only 'getName'
+```
+#### WeakSet
+Module [`es6.weak-set`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.weak-set.js).
+```js
+new WeakSet(iterable?) -> weakset
+ #add(key) -> @
+ #delete(key) -> bool
+ #has(key) -> bool
+```
+[*CommonJS entry points:*](#commonjs)
+```
+core-js(/library)/es6/weak-set
+core-js(/library)/fn/weak-set
+```
+[*Examples*](http://goo.gl/TdFbEx):
+```js
+var a = [1]
+ , b = [2]
+ , c = [3];
+
+var wset = new WeakSet([a, b, a]);
+wset.add(c).add(b).add(c);
+console.log(wset.has(b)); // => true
+console.log(wset.has([2])); // => false
+wset.delete(b);
+console.log(wset.has(b)); // => false
+```
+##### Caveats when using collections polyfill:
+
+* 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.
+
+#### ECMAScript 6: Typed Arrays
+Implementations 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.
+
+Modules [`es6.typed.array-buffer`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.typed.array-buffer.js), [`es6.typed.data-view`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.typed.data-view.js), [`es6.typed.int8-array`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.typed.int8-array.js), [`es6.typed.uint8-array`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.typed.uint8-array.js), [`es6.typed.uint8-clamped-array`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.typed.uint8-clamped-array.js), [`es6.typed.int16-array`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.typed.int16-array.js), [`es6.typed.uint16-array`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.typed.uint16-array.js), [`es6.typed.int32-array`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.typed.int32-array.js), [`es6.typed.uint32-array`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.typed.uint32-array.js), [`es6.typed.float32-array`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.typed.float32-array.js) and [`es6.typed.float64-array`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.typed.float64-array.js).
+```js
+new ArrayBuffer(length) -> buffer
+ .isView(var) -> bool
+ #slice(start = 0, end = @length) -> buffer
+ #byteLength -> uint
+
+new DataView(buffer, byteOffset = 0, byteLength = buffer.byteLength - byteOffset) -> view
+ #getInt8(offset) -> int8
+ #getUint8(offset) -> uint8
+ #getInt16(offset, littleEndian = false) -> int16
+ #getUint16(offset, littleEndian = false) -> uint16
+ #getInt32(offset, littleEndian = false) -> int32
+ #getUint32(offset, littleEndian = false) -> uint32
+ #getFloat32(offset, littleEndian = false) -> float32
+ #getFloat64(offset, littleEndian = false) -> float64
+ #setInt8(offset, value) -> void
+ #setUint8(offset, value) -> void
+ #setInt16(offset, value, littleEndian = false) -> void
+ #setUint16(offset, value, littleEndian = false) -> void
+ #setInt32(offset, value, littleEndian = false) -> void
+ #setUint32(offset, value, littleEndian = false) -> void
+ #setFloat32(offset, value, littleEndian = false) -> void
+ #setFloat64(offset, value, littleEndian = false) -> void
+ #buffer -> buffer
+ #byteLength -> uint
+ #byteOffset -> uint
+
+{
+ Int8Array,
+ Uint8Array,
+ Uint8ClampedArray,
+ Int16Array,
+ Uint16Array,
+ Int32Array,
+ Uint32Array,
+ Float32Array,
+ Float64Array
+}
+ new %TypedArray%(length) -> typed
+ new %TypedArray%(typed) -> typed
+ new %TypedArray%(arrayLike) -> typed
+ new %TypedArray%(iterable) -> typed
+ new %TypedArray%(buffer, byteOffset = 0, length = (buffer.byteLength - byteOffset) / @BYTES_PER_ELEMENT) -> typed
+ .BYTES_PER_ELEMENT -> uint
+ .from(arrayLike | iterable, mapFn(val, index)?, that) -> typed
+ .of(...args) -> typed
+ #BYTES_PER_ELEMENT -> uint
+ #copyWithin(target = 0, start = 0, end = @length) -> @
+ #every(fn(val, index, @), that) -> bool
+ #fill(val, start = 0, end = @length) -> @
+ #filter(fn(val, index, @), that) -> typed
+ #find(fn(val, index, @), that) -> val
+ #findIndex(fn(val, index, @), that) -> index
+ #forEach(fn(val, index, @), that) -> void
+ #indexOf(var, from?) -> int
+ #join(string = ',') -> string
+ #lastIndexOf(var, from?) -> int
+ #map(fn(val, index, @), that) -> typed
+ #reduce(fn(memo, val, index, @), memo?) -> var
+ #reduceRight(fn(memo, val, index, @), memo?) -> var
+ #reverse() -> @
+ #set(arrayLike, offset = 0) -> void
+ #slice(start = 0, end = @length) -> typed
+ #some(fn(val, index, @), that) -> bool
+ #sort(fn(a, b)?) -> @
+ #subarray(start = 0, end = @length) -> typed
+ #toString() -> string
+ #toLocaleString() -> string
+ #values() -> iterator
+ #keys() -> iterator
+ #entries() -> iterator
+ #@@iterator() -> iterator (values)
+ #buffer -> buffer
+ #byteLength -> uint
+ #byteOffset -> uint
+ #length -> uint
+```
+[*CommonJS entry points:*](#commonjs)
+```
+core-js(/library)/es6/typed
+core-js(/library)/fn/typed
+core-js(/library)/fn/typed/array-buffer
+core-js(/library)/fn/typed/data-view
+core-js(/library)/fn/typed/int8-array
+core-js(/library)/fn/typed/uint8-array
+core-js(/library)/fn/typed/uint8-clamped-array
+core-js(/library)/fn/typed/int16-array
+core-js(/library)/fn/typed/uint16-array
+core-js(/library)/fn/typed/int32-array
+core-js(/library)/fn/typed/uint32-array
+core-js(/library)/fn/typed/float32-array
+core-js(/library)/fn/typed/float64-array
+```
+[*Examples*](http://goo.gl/yla75z):
+```js
+new Int32Array(4); // => [0, 0, 0, 0]
+new Uint8ClampedArray([1, 2, 3, 666]); // => [1, 2, 3, 255]
+new Float32Array(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]
+
+var buffer = new ArrayBuffer(8);
+var view = new DataView(buffer);
+view.setFloat64(0, 123.456, true);
+new Uint8Array(buffer.slice(4)); // => [47, 221, 94, 64]
+
+Int8Array.of(1, 1.5, 5.7, 745); // => [1, 1, 5, -23]
+Uint8Array.from([1, 1.5, 5.7, 745]); // => [1, 1, 5, 233]
+
+var typed = new Uint8Array([1, 2, 3]);
+
+var a = typed.slice(1); // => [2, 3]
+typed.buffer === a.buffer; // => false
+var b = typed.subarray(1); // => [2, 3]
+typed.buffer === b.buffer; // => true
+
+typed.filter(it => it % 2); // => [1, 3]
+typed.map(it => it * 1.5); // => [1, 3, 4]
+
+for(var val of typed)console.log(val); // => 1, 2, 3
+for(var val of typed.values())console.log(val); // => 1, 2, 3
+for(var key of typed.keys())console.log(key); // => 0, 1, 2
+for(var [key, val] of typed.entries()){
+ console.log(key); // => 0, 1, 2
+ console.log(val); // => 1, 2, 3
+}
+```
+##### Caveats when using typed arrays:
+
+* 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.
+* The current version hasn't special entry points for methods, they can be added only with constructors. It can be added in the future.
+* In the `library` version we can't pollute native prototypes, so prototype methods available as constructors static.
+
+#### ECMAScript 6: Reflect
+Modules [`es6.reflect.apply`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.reflect.apply.js), [`es6.reflect.construct`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.reflect.construct.js), [`es6.reflect.define-property`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.reflect.define-property.js), [`es6.reflect.delete-property`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.reflect.delete-property.js), [`es6.reflect.enumerate`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.reflect.enumerate.js), [`es6.reflect.get`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.reflect.get.js), [`es6.reflect.get-own-property-descriptor`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.reflect.get-own-property-descriptor.js), [`es6.reflect.get-prototype-of`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.reflect.get-prototype-of.js), [`es6.reflect.has`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.reflect.has.js), [`es6.reflect.is-extensible`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.reflect.is-extensible.js), [`es6.reflect.own-keys`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.reflect.own-keys.js), [`es6.reflect.prevent-extensions`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.reflect.prevent-extensions.js), [`es6.reflect.set`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.reflect.set.js), [`es6.reflect.set-prototype-of`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es6.reflect.set-prototype-of.js).
+```js
+Reflect
+ .apply(target, thisArgument, argumentsList) -> var
+ .construct(target, argumentsList, newTarget?) -> object
+ .defineProperty(target, propertyKey, attributes) -> bool
+ .deleteProperty(target, propertyKey) -> bool
+ .enumerate(target) -> iterator (removed from the spec and will be removed from core-js@3)
+ .get(target, propertyKey, receiver?) -> var
+ .getOwnPropertyDescriptor(target, propertyKey) -> desc
+ .getPrototypeOf(target) -> object | null
+ .has(target, propertyKey) -> bool
+ .isExtensible(target) -> bool
+ .ownKeys(target) -> array
+ .preventExtensions(target) -> bool
+ .set(target, propertyKey, V, receiver?) -> bool
+ .setPrototypeOf(target, proto) -> bool (required __proto__ - IE11+)
+```
+[*CommonJS entry points:*](#commonjs)
+```
+core-js(/library)/es6/reflect
+core-js(/library)/fn/reflect
+core-js(/library)/fn/reflect/apply
+core-js(/library)/fn/reflect/construct
+core-js(/library)/fn/reflect/define-property
+core-js(/library)/fn/reflect/delete-property
+core-js(/library)/fn/reflect/enumerate (deprecated and will be removed from the next major release)
+core-js(/library)/fn/reflect/get
+core-js(/library)/fn/reflect/get-own-property-descriptor
+core-js(/library)/fn/reflect/get-prototype-of
+core-js(/library)/fn/reflect/has
+core-js(/library)/fn/reflect/is-extensible
+core-js(/library)/fn/reflect/own-keys
+core-js(/library)/fn/reflect/prevent-extensions
+core-js(/library)/fn/reflect/set
+core-js(/library)/fn/reflect/set-prototype-of
+```
+[*Examples*](http://goo.gl/gVT0cH):
+```js
+var O = {a: 1};
+Object.defineProperty(O, 'b', {value: 2});
+O[Symbol('c')] = 3;
+Reflect.ownKeys(O); // => ['a', 'b', Symbol(c)]
+
+function C(a, b){
+ this.c = a + b;
+}
+
+var instance = Reflect.construct(C, [20, 22]);
+instance.c; // => 42
+```
+
+### ECMAScript 7+ proposals
+[The TC39 process.](https://tc39.github.io/process-document/)
+
+[*CommonJS entry points:*](#commonjs)
+```
+core-js(/library)/es7
+core-js(/library)/es7/array
+core-js(/library)/es7/global
+core-js(/library)/es7/string
+core-js(/library)/es7/map
+core-js(/library)/es7/set
+core-js(/library)/es7/error
+core-js(/library)/es7/math
+core-js(/library)/es7/system
+core-js(/library)/es7/symbol
+core-js(/library)/es7/reflect
+core-js(/library)/es7/observable
+```
+`core-js/stage/4` entry point contains only stage 4 proposals, `core-js/stage/3` - stage 3 and stage 4, etc.
+#### Stage 4 proposals
+
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/stage/4
+```
+* `{Array, %TypedArray%}#includes` [proposal](https://github.com/tc39/Array.prototype.includes) - module [`es7.array.includes`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.array.includes.js), `%TypedArray%` version in modules from [this section](#ecmascript-6-typed-arrays).
+```js
+Array
+ #includes(var, from?) -> bool
+{
+ Int8Array,
+ Uint8Array,
+ Uint8ClampedArray,
+ Int16Array,
+ Uint16Array,
+ Int32Array,
+ Uint32Array,
+ Float32Array,
+ Float64Array
+}
+ #includes(var, from?) -> bool
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/array/includes
+```
+[*Examples*](http://goo.gl/2Gq4ma):
+```js
+[1, 2, 3].includes(2); // => true
+[1, 2, 3].includes(4); // => false
+[1, 2, 3].includes(2, 2); // => false
+
+[NaN].indexOf(NaN); // => -1
+[NaN].includes(NaN); // => true
+Array(1).indexOf(undefined); // => -1
+Array(1).includes(undefined); // => true
+```
+* `Object.values`, `Object.entries` [proposal](https://github.com/tc39/proposal-object-values-entries) - modules [`es7.object.values`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.object.values.js), [`es7.object.entries`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.object.entries.js)
+```js
+Object
+ .values(object) -> array
+ .entries(object) -> array
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/object/values
+core-js(/library)/fn/object/entries
+```
+[*Examples*](http://goo.gl/6kuGOn):
+```js
+Object.values({a: 1, b: 2, c: 3}); // => [1, 2, 3]
+Object.entries({a: 1, b: 2, c: 3}); // => [['a', 1], ['b', 2], ['c', 3]]
+
+for(let [key, value] of Object.entries({a: 1, b: 2, c: 3})){
+ console.log(key); // => 'a', 'b', 'c'
+ console.log(value); // => 1, 2, 3
+}
+```
+* `Object.getOwnPropertyDescriptors` [proposal](https://github.com/tc39/proposal-object-getownpropertydescriptors) - module [`es7.object.get-own-property-descriptors`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.object.get-own-property-descriptors.js)
+```js
+Object
+ .getOwnPropertyDescriptors(object) -> object
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/object/get-own-property-descriptors
+```
+*Examples*:
+```js
+// Shallow object cloning with prototype and descriptors:
+var copy = Object.create(Object.getPrototypeOf(O), Object.getOwnPropertyDescriptors(O));
+// Mixin:
+Object.defineProperties(target, Object.getOwnPropertyDescriptors(source));
+```
+* `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/v2.5.0/modules/es7.string.pad-start.js), [`es7.string.pad-end`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.string.pad-end.js)
+```js
+String
+ #padStart(length, fillStr = ' ') -> string
+ #padEnd(length, fillStr = ' ') -> string
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/string/pad-start
+core-js(/library)/fn/string/pad-end
+core-js(/library)/fn/string/virtual/pad-start
+core-js(/library)/fn/string/virtual/pad-end
+```
+[*Examples*](http://goo.gl/hK5ccv):
+```js
+'hello'.padStart(10); // => ' hello'
+'hello'.padStart(10, '1234'); // => '12341hello'
+'hello'.padEnd(10); // => 'hello '
+'hello'.padEnd(10, '1234'); // => 'hello12341'
+```
+* `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/v2.5.0/modules/es7.object.define-setter.js), [`es7.object.define-getter`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.object.define-getter.js), [`es7.object.lookup-setter`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.object.lookup-setter.js) and [`es7.object.lookup-getter`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.object.lookup-getter.js).
+```js
+Object
+ #__defineSetter__(key, fn) -> void
+ #__defineGetter__(key, fn) -> void
+ #__lookupSetter__(key) -> fn | void
+ #__lookupGetter__(key) -> fn | void
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/object/define-getter
+core-js(/library)/fn/object/define-setter
+core-js(/library)/fn/object/lookup-getter
+core-js(/library)/fn/object/lookup-setter
+```
+
+#### Stage 3 proposals
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/stage/3
+```
+* `global` [proposal](https://github.com/tc39/proposal-global) - modules [`es7.global`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.global.js) and [`es7.system.global`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.system.global.js) (obsolete)
+```js
+global -> object
+System
+ .global -> object (obsolete)
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/global
+core-js(/library)/fn/system/global (obsolete)
+```
+[*Examples*](http://goo.gl/gEqMl7):
+```js
+global.Array === Array; // => true
+```
+* `Promise#finally` [proposal](https://github.com/tc39/proposal-promise-finally) - module [`es7.promise.finally`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.promise.finally.js)
+```js
+Promise
+ #finally(onFinally()) -> promise
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/promise/finally
+```
+[*Examples*](https://goo.gl/AhyBbJ):
+```js
+Promise.resolve(42).finally(() => console.log('You will see it anyway'));
+
+Promise.reject(42).finally(() => console.log('You will see it anyway'));
+```
+
+#### Stage 2 proposals
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/stage/2
+```
+* `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/v2.5.0/modules/es7.symbol.async-iterator.js)
+```js
+Symbol
+ .asyncIterator -> @@asyncIterator
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/symbol/async-iterator
+```
+* `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/v2.5.0/modules/es7.string.trim-right.js), [`es7.string.trim-right`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.string.trim-right.js)
+```js
+String
+ #trimLeft() -> string
+ #trimRight() -> string
+ #trimStart() -> string
+ #trimEnd() -> string
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/string/trim-start
+core-js(/library)/fn/string/trim-end
+core-js(/library)/fn/string/trim-left
+core-js(/library)/fn/string/trim-right
+core-js(/library)/fn/string/virtual/trim-start
+core-js(/library)/fn/string/virtual/trim-end
+core-js(/library)/fn/string/virtual/trim-left
+core-js(/library)/fn/string/virtual/trim-right
+```
+[*Examples*](http://goo.gl/Er5lMJ):
+```js
+' hello '.trimLeft(); // => 'hello '
+' hello '.trimRight(); // => ' hello'
+```
+
+#### Stage 1 proposals
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/stage/1
+```
+* `Promise.try` [proposal](https://github.com/tc39/proposal-promise-try) - module [`es7.promise.try`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.promise.try.js)
+```js
+Promise
+ .try(function()) -> promise
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/promise/try
+```
+[*Examples*](https://goo.gl/k5GGRo):
+```js
+Promise.try(() => 42).then(it => console.log(`Promise, resolved as ${it}`));
+
+Promise.try(() => { throw 42; }).catch(it => console.log(`Promise, rejected as ${it}`));
+```
+* `Array#flatten` and `Array#flatMap` [proposal](https://tc39.github.io/proposal-flatMap) - modules [`es7.array.flatten`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.array.flatten.js) and [`es7.array.flat-map`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.array.flat-map.js)
+```js
+Array
+ #flatten(depthArg = 1) -> array
+ #flatMap(fn(val, key, @), that) -> array
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/array/flatten
+core-js(/library)/fn/array/flatMap
+core-js(/library)/fn/array/virtual/flatten
+core-js(/library)/fn/array/virtual/flatMap
+```
+[*Examples*](https://goo.gl/jTXsZi):
+```js
+[1, [2, 3], [4, 5]].flatten(); // => [1, 2, 3, 4, 5]
+[1, [2, [3, [4]]], 5].flatten(); // => [1, 2, [3, [4]], 5]
+[1, [2, [3, [4]]], 5].flatten(3); // => [1, 2, 3, 4, 5]
+
+[{a: 1, b: 2}, {a: 3, b: 4}, {a: 5, b: 6}].flatMap(it => [it.a, it.b]); // => [1, 2, 3, 4, 5, 6]
+```
+* `.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/v2.5.0/modules/es7.set.of.js), [`es7.set.from`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.set.from.js), [`es7.map.of`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.map.of.js), [`es7.map.from`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.map.from.js), [`es7.weak-set.of`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.weak-set.of.js), [`es7.weak-set.from`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.weak-set.from.js), [`es7.weak-map.of`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.weak-map.of.js), [`es7.weak-map.from`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.weak-map.from.js)
+```js
+Set
+ .of(...args) -> set
+ .from(iterable, mapFn(val, index)?, that?) -> set
+Map
+ .of(...args) -> map
+ .from(iterable, mapFn(val, index)?, that?) -> map
+WeakSet
+ .of(...args) -> weakset
+ .from(iterable, mapFn(val, index)?, that?) -> weakset
+WeakMap
+ .of(...args) -> weakmap
+ .from(iterable, mapFn(val, index)?, that?) -> weakmap
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/set/of
+core-js(/library)/fn/set/from
+core-js(/library)/fn/map/of
+core-js(/library)/fn/map/from
+core-js(/library)/fn/weak-set/of
+core-js(/library)/fn/weak-set/from
+core-js(/library)/fn/weak-map/of
+core-js(/library)/fn/weak-map/from
+```
+[*Examples*](https://goo.gl/mSC7eU):
+```js
+Set.of(1, 2, 3, 2, 1); // => Set {1, 2, 3}
+
+Map.from([[1, 2], [3, 4]], ([key, val]) => [key ** 2, val ** 2]); // => Map {1: 4, 9: 16}
+```
+* `String#matchAll` [proposal](https://github.com/tc39/String.prototype.matchAll) - module [`es7.string.match-all`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.string.match-all.js)
+```js
+String
+ #matchAll(regexp) -> iterator
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/string/match-all
+core-js(/library)/fn/string/virtual/match-all
+```
+[*Examples*](http://goo.gl/6kp9EB):
+```js
+for(let [_, d, D] of '1111a2b3cccc'.matchAll(/(\d)(\D)/)){
+ console.log(d, D); // => 1 a, 2 b, 3 c
+}
+```
+* `Observable` [proposal](https://github.com/zenparsing/es-observable) - modules [`es7.observable`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.observable.js) and [`es7.symbol.observable`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.symbol.observable.js)
+```js
+new Observable(fn) -> observable
+ #subscribe(observer) -> subscription
+ #forEach(fn) -> promise
+ #@@observable() -> @
+ .of(...items) -> observable
+ .from(observable | iterable) -> observable
+ .@@species -> @
+Symbol
+ .observable -> @@observable
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/observable
+core-js(/library)/fn/symbol/observable
+```
+[*Examples*](http://goo.gl/1LDywi):
+```js
+new Observable(observer => {
+ observer.next('hello');
+ observer.next('world');
+ observer.complete();
+}).forEach(it => console.log(it))
+ .then(_ => console.log('!'));
+```
+* `Math.{clamp, DEG_PER_RAD, degrees, fscale, rad-per-deg, radians, scale}`
+ [proposal](https://github.com/rwaldron/proposal-math-extensions) - modules
+ [`es7.math.clamp`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.math.clamp.js),
+ [`es7.math.DEG_PER_RAD`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.math.DEG_PER_RAD.js),
+ [`es7.math.degrees`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.math.degrees.js),
+ [`es7.math.fscale`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.math.fscale.js),
+ [`es7.math.RAD_PER_DEG`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.math.RAD_PER_DEG.js),
+ [`es7.math.radians`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.math.radians.js) and
+ [`es7.math.scale`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.math.scale.js)
+```js
+Math
+ .DEG_PER_RAD -> number
+ .RAD_PER_DEG -> number
+ .clamp(x, lower, upper) -> number
+ .degrees(radians) -> number
+ .fscale(x, inLow, inHigh, outLow, outHigh) -> number
+ .radians(degrees) -> number
+ .scale(x, inLow, inHigh, outLow, outHigh) -> number
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/math/clamp
+core-js(/library)/fn/math/deg-per-rad
+core-js(/library)/fn/math/degrees
+core-js(/library)/fn/math/fscale
+core-js(/library)/fn/math/rad-per-deg
+core-js(/library)/fn/math/radians
+core-js(/library)/fn/math/scale
+```
+* `Math.signbit` [proposal](http://jfbastien.github.io/papers/Math.signbit.html) - module [`es7.math.signbit`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.math.signbit.js)
+```js
+Math
+ .signbit(x) -> bool
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/math/signbit
+```
+[*Examples*](http://es6.zloirock.ru/):
+```js
+Math.signbit(NaN); // => NaN
+Math.signbit(1); // => true
+Math.signbit(-1); // => false
+Math.signbit(0); // => true
+Math.signbit(-0); // => false
+```
+
+#### Stage 0 proposals
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/stage/0
+```
+* `String#at` [proposal](https://github.com/mathiasbynens/String.prototype.at) - module [`es7.string.at`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.string.at.js)
+```js
+String
+ #at(index) -> string
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/string/at
+core-js(/library)/fn/string/virtual/at
+```
+[*Examples*](http://goo.gl/XluXI8):
+```js
+'a𠮷b'.at(1); // => '𠮷'
+'a𠮷b'.at(1).length; // => 2
+```
+* `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/v2.5.0/modules/es7.map.to-json.js), [`es7.set.to-json`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.set.to-json.js) (rejected and will be removed from `core-js@3`)
+```js
+Map
+ #toJSON() -> array (rejected and will be removed from core-js@3)
+Set
+ #toJSON() -> array (rejected and will be removed from core-js@3)
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/map
+core-js(/library)/fn/set
+```
+* `Error.isError` [proposal](https://github.com/ljharb/proposal-is-error) - module [`es7.error.is-error`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.error.is-error.js) (withdrawn and will be removed from `core-js@3`)
+```js
+Error
+ .isError(it) -> bool (withdrawn and will be removed from core-js@3)
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/error/is-error
+```
+* `Math.{iaddh, isubh, imulh, umulh}` [proposal](https://gist.github.com/BrendanEich/4294d5c212a6d2254703) - modules [`es7.math.iaddh`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.math.iaddh.js), [`es7.math.isubh`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.math.isubh.js), [`es7.math.imulh`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.math.imulh.js) and [`es7.math.umulh`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.math.umulh.js)
+```js
+Math
+ .iaddh(lo0, hi0, lo1, hi1) -> int32
+ .isubh(lo0, hi0, lo1, hi1) -> int32
+ .imulh(a, b) -> int32
+ .umulh(a, b) -> uint32
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/math/iaddh
+core-js(/library)/fn/math/isubh
+core-js(/library)/fn/math/imulh
+core-js(/library)/fn/math/umulh
+```
+* `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/v2.5.0/modules/es7.asap.js)
+```js
+asap(fn) -> void
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/asap
+```
+[*Examples*](http://goo.gl/tx3SRK):
+```js
+asap(() => console.log('called as microtask'));
+```
+
+#### Pre-stage 0 proposals
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/stage/pre
+```
+* `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/v2.5.0/modules/es7.reflect.define-metadata.js), [`es7.reflect.delete-metadata`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.reflect.delete-metadata.js), [`es7.reflect.get-metadata`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.reflect.get-metadata.js), [`es7.reflect.get-metadata-keys`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.reflect.get-metadata-keys.js), [`es7.reflect.get-own-metadata`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.reflect.get-own-metadata.js), [`es7.reflect.get-own-metadata-keys`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.reflect.get-own-metadata-keys.js), [`es7.reflect.has-metadata`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.reflect.has-metadata.js), [`es7.reflect.has-own-metadata`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.reflect.has-own-metadata.js) and [`es7.reflect.metadata`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/es7.reflect.metadata.js).
+```js
+Reflect
+ .defineMetadata(metadataKey, metadataValue, target, propertyKey?) -> void
+ .getMetadata(metadataKey, target, propertyKey?) -> var
+ .getOwnMetadata(metadataKey, target, propertyKey?) -> var
+ .hasMetadata(metadataKey, target, propertyKey?) -> bool
+ .hasOwnMetadata(metadataKey, target, propertyKey?) -> bool
+ .deleteMetadata(metadataKey, target, propertyKey?) -> bool
+ .getMetadataKeys(target, propertyKey?) -> array
+ .getOwnMetadataKeys(target, propertyKey?) -> array
+ .metadata(metadataKey, metadataValue) -> decorator(target, targetKey?) -> void
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/reflect/define-metadata
+core-js(/library)/fn/reflect/delete-metadata
+core-js(/library)/fn/reflect/get-metadata
+core-js(/library)/fn/reflect/get-metadata-keys
+core-js(/library)/fn/reflect/get-own-metadata
+core-js(/library)/fn/reflect/get-own-metadata-keys
+core-js(/library)/fn/reflect/has-metadata
+core-js(/library)/fn/reflect/has-own-metadata
+core-js(/library)/fn/reflect/metadata
+```
+[*Examples*](http://goo.gl/KCo3PS):
+```js
+var O = {};
+Reflect.defineMetadata('foo', 'bar', O);
+Reflect.ownKeys(O); // => []
+Reflect.getOwnMetadataKeys(O); // => ['foo']
+Reflect.getOwnMetadata('foo', O); // => 'bar'
+```
+
+### Web standards
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/web
+```
+#### setTimeout / setInterval
+Module [`web.timers`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/web.timers.js). Additional arguments fix for IE9-.
+```js
+setTimeout(fn(...args), time, ...args) -> id
+setInterval(fn(...args), time, ...args) -> id
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/web/timers
+core-js(/library)/fn/set-timeout
+core-js(/library)/fn/set-interval
+```
+```js
+// Before:
+setTimeout(log.bind(null, 42), 1000);
+// After:
+setTimeout(log, 1000, 42);
+```
+#### setImmediate
+Module [`web.immediate`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/web.immediate.js). [`setImmediate` proposal](https://developer.mozilla.org/en-US/docs/Web/API/Window.setImmediate) polyfill.
+```js
+setImmediate(fn(...args), ...args) -> id
+clearImmediate(id) -> void
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/web/immediate
+core-js(/library)/fn/set-immediate
+core-js(/library)/fn/clear-immediate
+```
+[*Examples*](http://goo.gl/6nXGrx):
+```js
+setImmediate(function(arg1, arg2){
+ console.log(arg1, arg2); // => Message will be displayed with minimum delay
+}, 'Message will be displayed', 'with minimum delay');
+
+clearImmediate(setImmediate(function(){
+ console.log('Message will not be displayed');
+}));
+```
+#### Iterable DOM collections
+Some 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/v2.5.0/modules/web.dom.iterable.js):
+```js
+{
+ CSSRuleList,
+ CSSStyleDeclaration,
+ CSSValueList,
+ ClientRectList,
+ DOMRectList,
+ DOMStringList,
+ DOMTokenList,
+ DataTransferItemList,
+ FileList,
+ HTMLAllCollection,
+ HTMLCollection,
+ HTMLFormElement,
+ HTMLSelectElement,
+ MediaList,
+ MimeTypeArray,
+ NamedNodeMap,
+ NodeList,
+ PaintRequestList,
+ Plugin,
+ PluginArray,
+ SVGLengthList,
+ SVGNumberList,
+ SVGPathSegList,
+ SVGPointList,
+ SVGStringList,
+ SVGTransformList,
+ SourceBufferList,
+ StyleSheetList,
+ TextTrackCueList,
+ TextTrackList,
+ TouchList
+}
+ #@@iterator() -> iterator (values)
+
+{
+ DOMTokenList,
+ NodeList
+}
+ #values() -> iterator
+ #keys() -> iterator
+ #entries() -> iterator
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/web/dom-collections
+core-js(/library)/fn/dom-collections/iterator
+```
+[*Examples*](http://goo.gl/lfXVFl):
+```js
+for(var {id} of document.querySelectorAll('*')){
+ if(id)console.log(id);
+}
+
+for(var [index, {id}] of document.querySelectorAll('*').entries()){
+ if(id)console.log(index, id);
+}
+```
+### Non-standard
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/core
+```
+#### Object
+Modules [`core.object.is-object`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/core.object.is-object.js), [`core.object.classof`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/core.object.classof.js), [`core.object.define`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/core.object.define.js), [`core.object.make`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/core.object.make.js).
+```js
+Object
+ .isObject(var) -> bool
+ .classof(var) -> string
+ .define(target, mixin) -> target
+ .make(proto | null, mixin?) -> object
+```
+
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/core/object
+core-js(/library)/fn/object/is-object
+core-js(/library)/fn/object/define
+core-js(/library)/fn/object/make
+```
+Object classify [*examples*](http://goo.gl/YZQmGo):
+```js
+Object.isObject({}); // => true
+Object.isObject(isNaN); // => true
+Object.isObject(null); // => false
+
+var classof = Object.classof;
+
+classof(null); // => 'Null'
+classof(undefined); // => 'Undefined'
+classof(1); // => 'Number'
+classof(true); // => 'Boolean'
+classof('string'); // => 'String'
+classof(Symbol()); // => 'Symbol'
+
+classof(new Number(1)); // => 'Number'
+classof(new Boolean(true)); // => 'Boolean'
+classof(new String('string')); // => 'String'
+
+var fn = function(){}
+ , list = (function(){return arguments})(1, 2, 3);
+
+classof({}); // => 'Object'
+classof(fn); // => 'Function'
+classof([]); // => 'Array'
+classof(list); // => 'Arguments'
+classof(/./); // => 'RegExp'
+classof(new TypeError); // => 'Error'
+
+classof(new Set); // => 'Set'
+classof(new Map); // => 'Map'
+classof(new WeakSet); // => 'WeakSet'
+classof(new WeakMap); // => 'WeakMap'
+classof(new Promise(fn)); // => 'Promise'
+
+classof([].values()); // => 'Array Iterator'
+classof(new Set().values()); // => 'Set Iterator'
+classof(new Map().values()); // => 'Map Iterator'
+
+classof(Math); // => 'Math'
+classof(JSON); // => 'JSON'
+
+function Example(){}
+Example.prototype[Symbol.toStringTag] = 'Example';
+
+classof(new Example); // => 'Example'
+```
+`Object.define` and `Object.make` [*examples*](http://goo.gl/rtpD5Z):
+```js
+// Before:
+Object.defineProperty(target, 'c', {
+ enumerable: true,
+ configurable: true,
+ get: function(){
+ return this.a + this.b;
+ }
+});
+
+// After:
+Object.define(target, {
+ get c(){
+ return this.a + this.b;
+ }
+});
+
+// Shallow object cloning with prototype and descriptors:
+var copy = Object.make(Object.getPrototypeOf(src), src);
+
+// Simple inheritance:
+function Vector2D(x, y){
+ this.x = x;
+ this.y = y;
+}
+Object.define(Vector2D.prototype, {
+ get xy(){
+ return Math.hypot(this.x, this.y);
+ }
+});
+function Vector3D(x, y, z){
+ Vector2D.apply(this, arguments);
+ this.z = z;
+}
+Vector3D.prototype = Object.make(Vector2D.prototype, {
+ constructor: Vector3D,
+ get xyz(){
+ return Math.hypot(this.x, this.y, this.z);
+ }
+});
+
+var vector = new Vector3D(9, 12, 20);
+console.log(vector.xy); // => 15
+console.log(vector.xyz); // => 25
+vector.y++;
+console.log(vector.xy); // => 15.811388300841896
+console.log(vector.xyz); // => 25.495097567963924
+```
+#### Dict
+Module [`core.dict`](https://github.com/zloirock/core-js/blob/v2.5.0/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).
+```js
+[new] Dict(iterable (entries) | object ?) -> dict
+ .isDict(var) -> bool
+ .values(object) -> iterator
+ .keys(object) -> iterator
+ .entries(object) -> iterator (entries)
+ .has(object, key) -> bool
+ .get(object, key) -> val
+ .set(object, key, value) -> object
+ .forEach(object, fn(val, key, @), that) -> void
+ .map(object, fn(val, key, @), that) -> new @
+ .mapPairs(object, fn(val, key, @), that) -> new @
+ .filter(object, fn(val, key, @), that) -> new @
+ .some(object, fn(val, key, @), that) -> bool
+ .every(object, fn(val, key, @), that) -> bool
+ .find(object, fn(val, key, @), that) -> val
+ .findKey(object, fn(val, key, @), that) -> key
+ .keyOf(object, var) -> key
+ .includes(object, var) -> bool
+ .reduce(object, fn(memo, val, key, @), memo?) -> var
+```
+
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/core/dict
+core-js(/library)/fn/dict
+```
+`Dict` create object without prototype from iterable or simple object.
+
+[*Examples*](http://goo.gl/pnp8Vr):
+```js
+var map = new Map([['a', 1], ['b', 2], ['c', 3]]);
+
+Dict(); // => {__proto__: null}
+Dict({a: 1, b: 2, c: 3}); // => {__proto__: null, a: 1, b: 2, c: 3}
+Dict(map); // => {__proto__: null, a: 1, b: 2, c: 3}
+Dict([1, 2, 3].entries()); // => {__proto__: null, 0: 1, 1: 2, 2: 3}
+
+var dict = Dict({a: 42});
+dict instanceof Object; // => false
+dict.a; // => 42
+dict.toString; // => undefined
+'a' in dict; // => true
+'hasOwnProperty' in dict; // => false
+
+Dict.isDict({}); // => false
+Dict.isDict(Dict()); // => true
+```
+`Dict.keys`, `Dict.values` and `Dict.entries` returns iterators for objects.
+
+[*Examples*](http://goo.gl/xAvECH):
+```js
+var dict = {a: 1, b: 2, c: 3};
+
+for(var key of Dict.keys(dict))console.log(key); // => 'a', 'b', 'c'
+
+for(var val of Dict.values(dict))console.log(val); // => 1, 2, 3
+
+for(var [key, val] of Dict.entries(dict)){
+ console.log(key); // => 'a', 'b', 'c'
+ console.log(val); // => 1, 2, 3
+}
+
+new Map(Dict.entries(dict)); // => Map {a: 1, b: 2, c: 3}
+```
+Basic dict operations for objects with prototype [*examples*](http://goo.gl/B28UnG):
+```js
+'q' in {q: 1}; // => true
+'toString' in {}; // => true
+
+Dict.has({q: 1}, 'q'); // => true
+Dict.has({}, 'toString'); // => false
+
+({q: 1})['q']; // => 1
+({}).toString; // => function toString(){ [native code] }
+
+Dict.get({q: 1}, 'q'); // => 1
+Dict.get({}, 'toString'); // => undefined
+
+var O = {};
+O['q'] = 1;
+O['q']; // => 1
+O['__proto__'] = {w: 2};
+O['__proto__']; // => {w: 2}
+O['w']; // => 2
+
+var O = {};
+Dict.set(O, 'q', 1);
+O['q']; // => 1
+Dict.set(O, '__proto__', {w: 2});
+O['__proto__']; // => {w: 2}
+O['w']; // => undefined
+```
+Other methods of `Dict` module are static equialents of `Array.prototype` methods for dictionaries.
+
+[*Examples*](http://goo.gl/xFi1RH):
+```js
+var dict = {a: 1, b: 2, c: 3};
+
+Dict.forEach(dict, console.log, console);
+// => 1, 'a', {a: 1, b: 2, c: 3}
+// => 2, 'b', {a: 1, b: 2, c: 3}
+// => 3, 'c', {a: 1, b: 2, c: 3}
+
+Dict.map(dict, function(it){
+ return it * it;
+}); // => {a: 1, b: 4, c: 9}
+
+Dict.mapPairs(dict, function(val, key){
+ if(key != 'b')return [key + key, val * val];
+}); // => {aa: 1, cc: 9}
+
+Dict.filter(dict, function(it){
+ return it % 2;
+}); // => {a: 1, c: 3}
+
+Dict.some(dict, function(it){
+ return it === 2;
+}); // => true
+
+Dict.every(dict, function(it){
+ return it === 2;
+}); // => false
+
+Dict.find(dict, function(it){
+ return it > 2;
+}); // => 3
+Dict.find(dict, function(it){
+ return it > 4;
+}); // => undefined
+
+Dict.findKey(dict, function(it){
+ return it > 2;
+}); // => 'c'
+Dict.findKey(dict, function(it){
+ return it > 4;
+}); // => undefined
+
+Dict.keyOf(dict, 2); // => 'b'
+Dict.keyOf(dict, 4); // => undefined
+
+Dict.includes(dict, 2); // => true
+Dict.includes(dict, 4); // => false
+
+Dict.reduce(dict, function(memo, it){
+ return memo + it;
+}); // => 6
+Dict.reduce(dict, function(memo, it){
+ return memo + it;
+}, ''); // => '123'
+```
+#### Partial application
+Module [`core.function.part`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/core.function.part.js).
+```js
+Function
+ #part(...args | _) -> fn(...args)
+```
+
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js/core/function
+core-js(/library)/fn/function/part
+core-js(/library)/fn/function/virtual/part
+core-js(/library)/fn/_
+```
+`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`.
+
+[*Examples*](http://goo.gl/p9ZJ8K):
+```js
+var fn1 = log.part(1, 2);
+fn1(3, 4); // => 1, 2, 3, 4
+
+var fn2 = log.part(_, 2, _, 4);
+fn2(1, 3); // => 1, 2, 3, 4
+
+var fn3 = log.part(1, _, _, 4);
+fn3(2, 3); // => 1, 2, 3, 4
+
+fn2(1, 3, 5); // => 1, 2, 3, 4, 5
+fn2(1); // => 1, 2, undefined, 4
+```
+#### Number Iterator
+Module [`core.number.iterator`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/core.number.iterator.js).
+```js
+Number
+ #@@iterator() -> iterator
+```
+
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/core/number
+core-js(/library)/fn/number/iterator
+core-js(/library)/fn/number/virtual/iterator
+```
+[*Examples*](http://goo.gl/o45pCN):
+```js
+for(var i of 3)console.log(i); // => 0, 1, 2
+
+[...10]; // => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+
+Array.from(10, Math.random); // => [0.9817775336559862, 0.02720663254149258, ...]
+
+Array.from(10, function(it){
+ return this + it * it;
+}, .42); // => [0.42, 1.42, 4.42, 9.42, 16.42, 25.42, 36.42, 49.42, 64.42, 81.42]
+```
+#### Escaping strings
+Modules [`core.regexp.escape`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/core.regexp.escape.js), [`core.string.escape-html`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/core.string.escape-html.js) and [`core.string.unescape-html`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/core.string.unescape-html.js).
+```js
+RegExp
+ .escape(str) -> str
+String
+ #escapeHTML() -> str
+ #unescapeHTML() -> str
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/core/regexp
+core-js(/library)/core/string
+core-js(/library)/fn/regexp/escape
+core-js(/library)/fn/string/escape-html
+core-js(/library)/fn/string/unescape-html
+core-js(/library)/fn/string/virtual/escape-html
+core-js(/library)/fn/string/virtual/unescape-html
+```
+[*Examples*](http://goo.gl/6bOvsQ):
+```js
+RegExp.escape('Hello, []{}()*+?.\\^$|!'); // => 'Hello, \[\]\{\}\(\)\*\+\?\.\\\^\$\|!'
+
+'<script>doSomething();</script>'.escapeHTML(); // => '&lt;script&gt;doSomething();&lt;/script&gt;'
+'&lt;script&gt;doSomething();&lt;/script&gt;'.unescapeHTML(); // => '<script>doSomething();</script>'
+```
+#### delay
+Module [`core.delay`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/core.delay.js). [Promise](#ecmascript-6-promise)-returning delay function, [esdiscuss](https://esdiscuss.org/topic/promise-returning-delay-function).
+```js
+delay(ms) -> promise
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/core/delay
+core-js(/library)/fn/delay
+```
+[*Examples*](http://goo.gl/lbucba):
+```js
+delay(1e3).then(() => console.log('after 1 sec'));
+
+(async () => {
+ await delay(3e3);
+ console.log('after 3 sec');
+
+ while(await delay(3e3))console.log('each 3 sec');
+})();
+```
+#### Helpers for iterators
+Modules [`core.is-iterable`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/core.is-iterable.js), [`core.get-iterator`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/core.get-iterator.js), [`core.get-iterator-method`](https://github.com/zloirock/core-js/blob/v2.5.0/modules/core.get-iterator-method.js) - helpers for check iterability / get iterator in the `library` version or, for example, for `arguments` object:
+```js
+core
+ .isIterable(var) -> bool
+ .getIterator(iterable) -> iterator
+ .getIteratorMethod(var) -> function | undefined
+```
+[*CommonJS entry points:*](#commonjs)
+```js
+core-js(/library)/fn/is-iterable
+core-js(/library)/fn/get-iterator
+core-js(/library)/fn/get-iterator-method
+```
+[*Examples*](http://goo.gl/SXsM6D):
+```js
+var list = (function(){
+ return arguments;
+})(1, 2, 3);
+
+console.log(core.isIterable(list)); // true;
+
+var iter = core.getIterator(list);
+console.log(iter.next().value); // 1
+console.log(iter.next().value); // 2
+console.log(iter.next().value); // 3
+console.log(iter.next().value); // undefined
+
+core.getIterator({}); // TypeError: [object Object] is not iterable!
+
+var iterFn = core.getIteratorMethod(list);
+console.log(typeof iterFn); // 'function'
+var iter = iterFn.call(list);
+console.log(iter.next().value); // 1
+console.log(iter.next().value); // 2
+console.log(iter.next().value); // 3
+console.log(iter.next().value); // undefined
+
+console.log(core.getIteratorMethod({})); // undefined
+```
+
+## Missing polyfills
+- 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).
+- 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/).
+- 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.
+- 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.
+- 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).
+- `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).
+- ECMA-402 `Intl` is missed because of size. You can use [this polyfill](https://github.com/andyearnshaw/Intl.js/).
generated by cgit v1.2.3 (git 2.39.1) at 2025-09-28 18:52:27 +0000