It's documentation for the unstable core-js@3
, if you looking documentation for core-js@2
, please, check this branch.
Modular standard library for JavaScript. Includes polyfills for ECMAScript up to 2019: promises, symbols, collections, iterators, typed arrays, many other features, ECMAScript proposals, some cross-platform WHATWG / W3C ECMAScript-related features and proposals like setImmediate. You can load only required features or use it without global namespace pollution.
import 'core-js'; // <- at the top of your entry point
Array.from(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]
[1, [2, 3], [4, [5]]].flat(2); // => [1, 2, 3, 4, 5]
Promise.resolve(32).then(x => console.log(x)); // => 32
You can load only required features:
import 'core-js/features/array/from'; // <- at the top of your entry point
import 'core-js/features/array/flat'; // <- at the top of your entry point
import 'core-js/features/set'; // <- at the top of your entry point
import 'core-js/features/promise'; // <- at the top of your entry point
Array.from(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]
[1, [2, 3], [4, [5]]].flat(2); // => [1, 2, 3, 4, 5]
Promise.resolve(32).then(x => console.log(x)); // => 32
Or use it without global namespace pollution:
import from from 'core-js-pure/features/array/from';
import flat from 'core-js-pure/features/array/flat';
import Set from 'core-js-pure/features/set';
import Promise from 'core-js-pure/features/promise';
from(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]
flat([1, [2, 3], [4, [5]]], 2); // => [1, 2, 3, 4, 5]
Promise.resolve(32).then(x => console.log(x)); // => 32
- Usage
- Supported engines
- Features
- Missing polyfills
- Contributing
- Changelog
Installation:
// global version
npm i [email protected]
// version without global namespace pollution
npm i [email protected]
// bundled global version
npm i [email protected]
// Include all polyfills
require('core-js');
If you need already bundled version of core-js
, use core-js-bundle
npm
package or a version of this package from CDN (minified version).
Warning: if you use core-js
with the extension of native objects, load all core-js
modules at the top of entry point of your application, otherwise, you can have conflicts.
You can require only needed modules, like in examples at the top of README.md
. Available entry points for methods / constructors and namespaces: for example, core-js/es/array
(core-js-pure/es/array
) contains all ES Array
features, core-js/es
(core-js-pure/es
) contains all ES features.
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 upcore-js
instead of usage loader for each file, otherwise, you will have hundreds of requests.
In the pure
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. Special for that, available /virtual/
entry points. Example:
import fill from 'core-js-pure/features/array/virtual/fill';
import findIndex from 'core-js-pure/features/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-pure/features/array/virtual';
Array(10)::fill(0).map((a, b) => b * b)::findIndex(it => it && !(it % 8)); // => 4
core-js
integrated to some parts of babel
:
@babel/polyfill
IS core-js
and regenerator-runtime
for generators and async functions, it's just 2 lines, so if you load @babel/polyfill
- you load the full global version of core-js
.
@babel/runtime
simplifies work with core-js-pure
. It automatically replaces usage of modern features from ECMAScript standard library to imports from the version of core-js
without global namespace pollution, so instead of:
import from from 'core-js-pure/features/array/from';
import Set from 'core-js-pure/features/set';
import Promise from 'core-js-pure/features/promise';
from(new Set([1, 2, 3, 2, 1]));
Promise.resolve(32).then(x => console.log(x));
you can write just:
Array.from(new Set([1, 2, 3, 2, 1]));
Promise.resolve(32).then(x => console.log(x));
At this moment, it does not work with instance methods, only globals and statics.
@babel/preset-env
has useBuiltIns
option, which optimizes work with polyfill. It works only with stable ECMAScript features, polyfills for ECMAScript proposals you should import separately.
useBuiltIns: 'entry'
replacesimport '@babel/polyfill'
orimport 'core-js'
to import only required features for the target environment. So, for example, for enough modern target,
import 'core-js';
will be replaced to something like:
import 'core-js/modules/es.promise.finally';
import 'core-js/modules/es.string.pad-start';
import 'core-js/modules/es.string.pad-end';
// ...
useBuiltIns: 'usage'
adds at the top of each file imports of polyfills for features used in this file, so for:
// first file:
var set = new Set();
// second file:
var array = Array.of(1, 2, 3);
if target contains old environments without support those ECMAScript features we will have:
// first file:
import 'core-js/modules/es.set';
var set = new Set();
// second file:
import 'core-js/modules/es.array.of';
var array = Array.of(1, 2, 3);
In this case, feature detection is not perfect. Also, import of polyfills not at the top of your entry point can cause problems.
By default, core-js
set polyfills only when they required. That means that core-js
check is a feature available and works it correctly or not and if it has no problems, core-js
use native implementation.
But sometimes core-js
feature detection could be too strict for your case. For example, Promise
constructor requires the support of unhandled rejection tracking and @@species
.
Sometimes we could have inverse problem - knowingly broken environment with problems not covered by core-js
feature detection.
For those cases, we could redefine this behaviour for certain polyfills:
import configurator from 'core-js/configurator';
configurator({
useNative: ['Promise'], // polyfills will be used only if natives completely unavailable
usePolyfill: ['Array.from', 'String.prototype.padEnd'], // polyfills will be used anyway
useFeatureDetection: ['Map', 'Set'], // default behaviour
});
import 'core-js';
It does not work with some features. Also, if you change the default behavior, even core-js
internals may not work correctly.
For some cases could be useful add a blacklist of features. core-js-builder
package exports a function. This will conditionally include or exclude certain parts of core-js
:
require('core-js-builder')({
modules: ['es', 'esnext.reflect', 'web'], // modules / namespaces
blacklist: ['es.math', 'es.number.constructor'], // blacklist of modules / namespaces, by default - empty list
}).then(code => {
// ...
}).catch(error => {
// ...
});
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.
core-js(-pure)
core-js(-pure)/es
Modules es.object.assign
, es.object.is
, es.object.set-prototype-of
, es.object.to-string
, es.object.freeze
, es.object.seal
, es.object.prevent-extensions
, es.object.is-frozen
, es.object.is-sealed
, es.object.is-extensible
, es.object.get-own-property-descriptor
, es.object.get-own-property-descriptors
, es.object.get-prototype-of
, es.object.keys
, es.object.values
, es.object.entries
and es.object.get-own-property-names
.
Just ES5 features: es.object.create
, es.object.define-property
and es.object.define-properties
.
ES2017 Annex B - modules es.object.define-setter
, es.object.define-getter
, es.object.lookup-setter
and es.object.lookup-getter
class Object {
toString(): string; // ES2015+ fix: @@toStringTag support
__defineGetter__(property: PropertyKey, getter: Function): void;
__defineSetter__(property: PropertyKey, setter: Function): void;
__lookupGetter__(property: PropertyKey): Function | void;
__lookupSetter__(property: PropertyKey): Function | void;
static assign(target: Object, ...sources: Array<Object>): Object;
static create(prototype: Object | null, properties?: { [property: PropertyKey]: PropertyDescriptor }): Object;
static defineProperties(object: Object, properties: { [property: PropertyKey]: PropertyDescriptor })): Object;
static defineProperty(object: Object, property: PropertyKey, attributes: PropertyDescriptor): Object;
static entries(object: Object): Array<[string, mixed]>;
static freeze(object: any): any;
static getOwnPropertyDescriptor(object: any, property: PropertyKey): PropertyDescriptor | void;
static getOwnPropertyDescriptors(object: any): { [property: PropertyKey]: PropertyDescriptor };
static getOwnPropertyNames(object: any): Array<string>;
static getPrototypeOf(object: any): Object | null;
static is(value1: any, value2: any): boolean;
static isExtensible(object: any): boolean;
static isFrozen(object: any): boolean;
static isSealed(object: any): boolean;
static keys(object: any): Array<string>;
static preventExtensions(object: any): any;
static seal(object: any): any;
static setPrototypeOf(target: any, prototype: Object | null): any; // required __proto__ - IE11+
static values(object: any): Array<mixed>;
}
core-js(-pure)/es|features/object
core-js(-pure)/es|features/object/assign
core-js(-pure)/es|features/object/is
core-js(-pure)/es|features/object/set-prototype-of
core-js(-pure)/es|features/object/get-prototype-of
core-js(-pure)/es|features/object/create
core-js(-pure)/es|features/object/define-property
core-js(-pure)/es|features/object/define-properties
core-js(-pure)/es|features/object/get-own-property-descriptor
core-js(-pure)/es|features/object/get-own-property-descriptors
core-js(-pure)/es|features/object/keys
core-js(-pure)/es|features/object/values
core-js(-pure)/es|features/object/entries
core-js(-pure)/es|features/object/get-own-property-names
core-js(-pure)/es|features/object/freeze
core-js(-pure)/es|features/object/seal
core-js(-pure)/es|features/object/prevent-extensions
core-js(-pure)/es|features/object/is-frozen
core-js(-pure)/es|features/object/is-sealed
core-js(-pure)/es|features/object/is-extensible
core-js/es|features/object/to-string
core-js(-pure)/es|features/object/define-getter
core-js(-pure)/es|features/object/define-setter
core-js(-pure)/es|features/object/lookup-getter
core-js(-pure)/es|features/object/lookup-setter
let foo = { q: 1, w: 2 };
let bar = { e: 3, r: 4 };
let 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
let object = {
[Symbol.toStringTag]: 'Foo'
};
'' + object; // => '[object Foo]'
Object.keys('qwe'); // => ['0', '1', '2']
Object.getPrototypeOf('qwe') === String.prototype; // => true
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
}
// Shallow object cloning with prototype and descriptors:
let copy = Object.create(Object.getPrototypeOf(object), Object.getOwnPropertyDescriptors(object));
// Mixin:
Object.defineProperties(target, Object.getOwnPropertyDescriptors(source));
Modules es.function.name
, es.function.has-instance
. Just ES5: es.function.bind
.
class Function {
name: string;
bind(thisArg: any, ...args: Array<mixed>): Function;
@@hasInstance(value: any): boolean;
}
core-js/es|features/function
core-js/es|features/function/name
core-js/es|features/function/has-instance
core-js/es|features/function/bind
core-js/es|features/function/virtual/bind
(function foo() {}).name // => 'foo'
console.log.bind(console, 42)(43); // => 42 43
Modules es.array.from
, es.array.is-array
, es.array.of
, es.array.copy-within
, es.array.fill
, es.array.find
, es.array.find-index
, es.array.iterator
, es.array.includes
, es.array.slice
, es.array.join
, es.array.index-of
, es.array.last-index-of
, es.array.every
, es.array.some
, es.array.for-each
, es.array.map
, es.array.filter
, es.array.reduce
, es.array.reduce-right
, es.array.reverse
, es.array.sort
class Array {
concat(...args: Array<mixed>): Array<mixed>; // with adding support of @@isConcatSpreadable and @@species
copyWithin(target: number, start: number, end?: number): this;
entries(): Iterator<[index, value]>;
every(callbackfn: (value: any, index: number, target: any) => boolean, thisArg?: any): boolean;
fill(value: any, start?: number, end?: number): this;
filter(callbackfn: (value: any, index: number, target: any) => boolean, thisArg?: any): Array<mixed>; // with adding support of @@species
find(callbackfn: (value: any, index: number, target: any) => boolean), thisArg?: any): any;
findIndex(callbackfn: (value: any, index: number, target: any) => boolean, thisArg?: any): number;
forEach(callbackfn: (value: any, index: number, target: any) => void, thisArg?: any): void;
includes(searchElement: any, from?: number): boolean;
indexOf(searchElement: any, from?: number): number;
join(separator: string = ','): string;
keys(): Iterator<index>;
lastIndexOf(searchElement: any, from?: number): number;
map(mapFn: (value: any, index: number, target: any) => any, thisArg?: any): Array<mixed>; // with adding support of @@species
reduce(callbackfn: (memo: any, value: any, index: number, target: any) => any, initialValue?: any): any;
reduceRight(callbackfn: (memo: any, value: any, index: number, target: any) => any, initialValue?: any): any;
reverse(): this; // Safari 12.0 bug fix
slice(start?: number, end?: number): Array<mixed>; // with adding support of @@species
splice(start?: number, deleteCount?: number, ...items: Array<mixed>): Array<mixed>; // with adding support of @@species
some(callbackfn: (value: any, index: number, target: any) => boolean, thisArg?: any): boolean;
sort(comparefn?: (a: any, b: any) => number): this;
values(): Iterator<value>;
@@iterator(): Iterator<value>;
@@unscopables: { [newMethodNames: string]: true };
static from(items: Iterable | ArrayLike, mapFn?: (value: any, index: number) => any, thisArg?: any): Array<mixed>;
static isArray(value: any): boolean;
static of(...args: Array<mixed>): Array<mixed>;
}
class Arguments {
@@iterator(): Iterator<value>; // available only in core-js methods
}
core-js(-pure)/es|features/array
core-js(-pure)/es|features/array/from
core-js(-pure)/es|features/array/of
core-js(-pure)/es|features/array/is-array
core-js(-pure)/es|features/array/concat
core-js(-pure)/es|features/array/copy-within
core-js(-pure)/es|features/array/fill
core-js(-pure)/es|features/array/find
core-js(-pure)/es|features/array/find-index
core-js(-pure)/es|features/array/includes
core-js(-pure)/es|features/array/iterator
core-js(-pure)/es|features/array/values
core-js(-pure)/es|features/array/keys
core-js(-pure)/es|features/array/entries
core-js(-pure)/es|features/array/slice
core-js(-pure)/es|features/array/splice
core-js(-pure)/es|features/array/join
core-js(-pure)/es|features/array/index-of
core-js(-pure)/es|features/array/last-index-of
core-js(-pure)/es|features/array/every
core-js(-pure)/es|features/array/some
core-js(-pure)/es|features/array/for-each
core-js(-pure)/es|features/array/map
core-js(-pure)/es|features/array/filter
core-js(-pure)/es|features/array/reduce
core-js(-pure)/es|features/array/reduce-right
core-js(-pure)/es|features/array/reverse
core-js(-pure)/es|features/array/sort
core-js(-pure)/es|features/array/virtual/concat
core-js(-pure)/es|features/array/virtual/copy-within
core-js(-pure)/es|features/array/virtual/fill
core-js(-pure)/es|features/array/virtual/find
core-js(-pure)/es|features/array/virtual/find-index
core-js(-pure)/es|features/array/virtual/includes
core-js(-pure)/es|features/array/virtual/iterator
core-js(-pure)/es|features/array/virtual/values
core-js(-pure)/es|features/array/virtual/keys
core-js(-pure)/es|features/array/virtual/entries
core-js(-pure)/es|features/array/virtual/slice
core-js(-pure)/es|features/array/virtual/splice
core-js(-pure)/es|features/array/virtual/join
core-js(-pure)/es|features/array/virtual/index-of
core-js(-pure)/es|features/array/virtual/last-index-of
core-js(-pure)/es|features/array/virtual/every
core-js(-pure)/es|features/array/virtual/some
core-js(-pure)/es|features/array/virtual/for-each
core-js(-pure)/es|features/array/virtual/map
core-js(-pure)/es|features/array/virtual/filter
core-js(-pure)/es|features/array/virtual/reduce
core-js(-pure)/es|features/array/virtual/reduce-right
core-js(-pure)/es|features/array/virtual/reverse
core-js(-pure)/es|features/array/virtual/sort
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', it => it * it); // => [1, 4, 9]
Array.of(1); // => [1]
Array.of(1, 2, 3); // => [1, 2, 3]
let array = ['a', 'b', 'c'];
for (let value of array) console.log(value); // => 'a', 'b', 'c'
for (let value of array.values()) console.log(value); // => 'a', 'b', 'c'
for (let key of array.keys()) console.log(key); // => 0, 1, 2
for (let [key, value] of array.entries()) {
console.log(key); // => 0, 1, 2
console.log(value); // => 'a', 'b', 'c'
}
function isOdd(value) {
return value % 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]
[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
The main part of String
features: modules es.string.from-code-point
, es.string.raw
, es.string.iterator
, es.string.split
, es.string.code-point-at
, es.string.ends-with
, es.string.includes
, es.string.repeat
, es.string.pad-start
, es.string.pad-end
, es.string.starts-with
and es.string.trim
.
Addiing support of well-known symbols @@match
, @@replace
, @@search
and @@split
and direct .exec
calls to related String
methods, modules es.string.match
, es.string.replace
, es.string.search
and es.string.split
.
Annex B HTML methods. Ugly, but it's also the part of the spec. Modules es.string.anchor
, es.string.big
, es.string.blink
, es.string.bold
, es.string.fixed
, es.string.fontcolor
, es.string.fontsize
, es.string.italics
, es.string.link
, es.string.small
, es.string.strike
, es.string.sub
and es.string.sup
.
RegExp
features: modules es.regexp.constructor
and es.regexp.flags
.
class String {
static fromCodePoint(...codePoints: Array<number>): string;
static raw({ raw: Array<string> }, ...substitutions: Array<string>): string;
split(separator: string, limit?: number): Array<string>;
includes(searchString: string, position?: number): boolean;
startsWith(searchString: string, position?: number): boolean;
endsWith(searchString: string, position?: number): boolean;
repeat(count: number): string;
padStart(length: number, fillStr?: string = ' '): string;
padEnd(length: number, fillStr?: string = ' '): string;
codePointAt(pos: number): number | void;
match(template: any): any; // ES2015+ fix for support @@match
replace(template: any, replacer: any): any; // ES2015+ fix for support @@replace
search(template: any): any; // ES2015+ fix for support @@search
split(template: any, limit: any): any; // ES2015+ fix for support @@split, some fixes for old engines
trim(): string;
anchor(name: string): string;
big(): string;
blink(): string;
bold(): string;
fixed(): string;
fontcolor(color: string): string;
fontsize(size: any): string;
italics(): string;
link(url: string): string;
small(): string;
strike(): string;
sub(): string;
sup(): string;
@@iterator(): Iterator<characters>;
}
class RegExp {
constructor(pattern: RegExp | string, flags?: string): RegExp; // ES2015+ fix - can alter flags (IE9+)
exec(): Array<string | undefined> | null; // IE8- fixes
toString(): string; // ES2015+ fix - generic
@@match(string: string): Array | null;
@@replace(string: string, replaceValue: Function | string): string;
@@search(string: string): number;
@@split(string: string, limit: number): Array<string>;
get flags: string; // IE9+
}
core-js(-pure)/es|features/string
core-js(-pure)/es|features/string/from-code-point
core-js(-pure)/es|features/string/raw
core-js(-pure)/es|features/string/includes
core-js(-pure)/es|features/string/starts-with
core-js(-pure)/es|features/string/ends-with
core-js(-pure)/es|features/string/repeat
core-js(-pure)/es|features/string/pad-start
core-js(-pure)/es|features/string/pad-end
core-js(-pure)/es|features/string/code-point-at
core-js(-pure)/es|features/string/trim
core-js(-pure)/es|features/string/anchor
core-js(-pure)/es|features/string/big
core-js(-pure)/es|features/string/blink
core-js(-pure)/es|features/string/bold
core-js(-pure)/es|features/string/fixed
core-js(-pure)/es|features/string/fontcolor
core-js(-pure)/es|features/string/fontsize
core-js(-pure)/es|features/string/italics
core-js(-pure)/es|features/string/link
core-js(-pure)/es|features/string/small
core-js(-pure)/es|features/string/strike
core-js(-pure)/es|features/string/sub
core-js(-pure)/es|features/string/sup
core-js(-pure)/es|features/string/iterator
core-js(-pure)/es|features/string/virtual/includes
core-js(-pure)/es|features/string/virtual/starts-with
core-js(-pure)/es|features/string/virtual/ends-with
core-js(-pure)/es|features/string/virtual/repeat
core-js(-pure)/es|features/string/virtual/pad-start
core-js(-pure)/es|features/string/virtual/pad-end
core-js(-pure)/es|features/string/virtual/code-point-at
core-js(-pure)/es|features/string/virtual/trim
core-js(-pure)/es|features/string/virtual/anchor
core-js(-pure)/es|features/string/virtual/big
core-js(-pure)/es|features/string/virtual/blink
core-js(-pure)/es|features/string/virtual/bold
core-js(-pure)/es|features/string/virtual/fixed
core-js(-pure)/es|features/string/virtual/fontcolor
core-js(-pure)/es|features/string/virtual/fontsize
core-js(-pure)/es|features/string/virtual/italics
core-js(-pure)/es|features/string/virtual/link
core-js(-pure)/es|features/string/virtual/small
core-js(-pure)/es|features/string/virtual/strike
core-js(-pure)/es|features/string/virtual/sub
core-js(-pure)/es|features/string/virtual/sup
core-js(-pure)/es|features/string/virtual/iterator
core-js/es|features/regexp
core-js/es|features/regexp/constructor
core-js(-pure)/es|features/regexp/flags
core-js/es|features/regexp/to-string
core-js/es|features/regexp/match
core-js/es|features/regexp/replace
core-js/es|features/regexp/search
core-js/es|features/regexp/split
for (let value of 'a๐ ฎทb') {
console.log(value); // => 'a', '๐ ฎท', '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'
'hello'.padStart(10); // => ' hello'
'hello'.padStart(10, '1234'); // => '12341hello'
'hello'.padEnd(10); // => 'hello '
'hello'.padEnd(10, '1234'); // => 'hello12341'
'๐ ฎท'.codePointAt(0); // => 134071
String.fromCodePoint(97, 134071, 98); // => 'a๐ ฎทb'
let name = 'Bob';
String.raw`Hi\n${name}!`; // => 'Hi\\nBob!' (ES2015 template string syntax)
String.raw({ raw: 'test' }, 0, 1, 2); // => 't0e1s2t'
'foo'.bold(); // => '<b>foo</b>'
'bar'.anchor('a"b'); // => '<a name="a"b">bar</a>'
'baz'.link('http://example.com'); // => '<a href="http://example.com">baz</a>'
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'
Module es.number.constructor
. Number
constructor support binary and octal literals, example:
Number('0b1010101'); // => 85
Number('0o7654321'); // => 2054353
Modules es.number.epsilon
, es.number.is-finite
, es.number.is-integer
, es.number.is-nan
, es.number.is-safe-integer
, es.number.max-safe-integer
, es.number.min-safe-integer
, es.number.parse-float
, es.number.parse-int
, es.number.to-fixed
, es.number.to-precision
, es.parse-int
, es.parse-float
.
class Number {
constructor(value: any): number;
toFixed(digits: number): string;
toPrecision(precision: number): string;
static isFinite(number: any): boolean;
static isNaN(number: any): boolean;
static isInteger(number: any): boolean;
static isSafeInteger(number: any): boolean;
static parseFloat(string: string): number;
static parseInt(string: string, radix?: number = 10): number;
static EPSILON: number;
static MAX_SAFE_INTEGER: number;
static MIN_SAFE_INTEGER: number;
}
function parseFloat(string: string): number;
function parseInt(string: string, radix?: number = 10): number;
core-js(-pure)/es|features/number
core-js/es|features/number/constructor
core-js(-pure)/es|features/number/is-finite
core-js(-pure)/es|features/number/is-nan
core-js(-pure)/es|features/number/is-integer
core-js(-pure)/es|features/number/is-safe-integer
core-js(-pure)/es|features/number/parse-float
core-js(-pure)/es|features/number/parse-int
core-js(-pure)/es|features/number/epsilon
core-js(-pure)/es|features/number/max-safe-integer
core-js(-pure)/es|features/number/min-safe-integer
core-js(-pure)/es|features/number/to-fixed
core-js(-pure)/es|features/number/to-precision
core-js(-pure)/es|features/parse-float
core-js(-pure)/es|features/parse-int
Modules es.math.acosh
, es.math.asinh
, es.math.atanh
, es.math.cbrt
, es.math.clz32
, es.math.cosh
, es.math.expm1
, es.math.fround
, es.math.hypot
, es.math.imul
, es.math.log10
, es.math.log1p
, es.math.log2
, es.math.sign
, es.math.sinh
, es.math.tanh
, es.math.trunc
.
namespace Math {
acosh(number: number): number;
asinh(number: number): number;
atanh(number: number): number;
cbrt(number: number): number;
clz32(number: number): number;
cosh(number: number): number;
expm1(number: number): number;
fround(number: number): number;
hypot(...args: Array<number>): number;
imul(number1: number, number2: number): number;
log1p(number: number): number;
log10(number: number): number;
log2(number: number): number;
sign(number: number): 1 | -1 | 0 | -0 | NaN;
sinh(number: number): number;
tanh(number: number): number;
trunc(number: number): number;
}
core-js(-pure)/es|features/math
core-js(-pure)/es|features/math/acosh
core-js(-pure)/es|features/math/asinh
core-js(-pure)/es|features/math/atanh
core-js(-pure)/es|features/math/cbrt
core-js(-pure)/es|features/math/clz32
core-js(-pure)/es|features/math/cosh
core-js(-pure)/es|features/math/expm1
core-js(-pure)/es|features/math/fround
core-js(-pure)/es|features/math/hypot
core-js(-pure)/es|features/math/imul
core-js(-pure)/es|features/math/log1p
core-js(-pure)/es|features/math/log10
core-js(-pure)/es|features/math/log2
core-js(-pure)/es|features/math/sign
core-js(-pure)/es|features/math/sinh
core-js(-pure)/es|features/math/tanh
core-js(-pure)/es|features/math/trunc
Modules es.date.to-string
, ES5 features with fixes: es.date.now
, es.date.to-iso-string
, es.date.to-json
and es.date.to-primitive
.
class Date {
toISOString(): string;
toJSON(): string;
toString(): string;
@@toPrimitive(hint: 'default' | 'number' | 'string'): string | number;
static now(): number;
}
core-js/es|features/date
core-js/es|features/date/to-string
core-js(-pure)/es|features/date/now
core-js(-pure)/es|features/date/to-iso-string
core-js(-pure)/es|features/date/to-json
core-js(-pure)/es|features/date/to-primitive
new Date(NaN).toString(); // => 'Invalid Date'
Modules es.promise
and es.promise.finally
.
class Promise {
constructor(executor: (resolve: Function, reject: Function) => void): Promise;
then(onFulfilled: Function, onRejected: Function): Promise;
catch(onRejected: Function): Promise;
finally(onFinally: Function): Promise;
static resolve(x: any): Promise;
static reject(r: any): Promise;
static all(iterable: Iterable): Promise;
static race(iterable: Iterable): Promise;
}
core-js(-pure)/es|features/promise
core-js(-pure)/es|features/promise/finally
Basic example:
function sleepRandom(time) {
return new Promise((resolve, reject) => {
setTimeout(resolve, time * 1e3, 0 | Math.random() * 1e3);
});
}
console.log('Run'); // => Run
sleepRandom(5).then(result => {
console.log(result); // => 869, after 5 sec.
return sleepRandom(10);
}).then(result => {
console.log(result); // => 202, after 10 sec.
}).then(() => {
console.log('immediately after'); // => immediately after
throw Error('Irror!');
}).then(() => {
console.log('will not be displayed');
}).catch(x => console.log(x)); // => => Error: Irror!
Promise.resolve
and Promise.reject
example:
Promise.resolve(42).then(x => console.log(x)); // => 42
Promise.reject(42).catch(x => console.log(x)); // => 42
Promise.resolve($.getJSON('/data.json')); // => ES promise
Promise#finally
example:
Promise.resolve(42).finally(() => console.log('You will see it anyway'));
Promise.reject(42).finally(() => console.log('You will see it anyway'));
Promise.all
example:
Promise.all([
'foo',
sleepRandom(5),
sleepRandom(15),
sleepRandom(10) // after 15 sec:
]).then(x => console.log(x)); // => ['foo', 956, 85, 382]
Promise.race
example:
function timeLimit(promise, time) {
return Promise.race([promise, new Promise((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
Example with async functions:
let 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.
let [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, 'Error!');
console.log('Will not be displayed');
} catch (e) {
console.log(e); // => Error: 'Error!', after 5 sec.
}
})();
In Node.js, like in native implementation, available events unhandledRejection
and rejectionHandled
:
process.on('unhandledRejection', (reason, promise) => console.log('unhandled', reason, promise));
process.on('rejectionHandled', (promise) => console.log('handled', promise));
let promise = Promise.reject(42);
// unhandled 42 [object Promise]
setTimeout(() => promise.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:
window.addEventListener('unhandledrejection', e => console.log('unhandled', e.reason, e.promise));
window.addEventListener('rejectionhandled', e => console.log('handled', e.reason, e.promise));
// or
window.onunhandledrejection = e => console.log('unhandled', e.reason, e.promise);
window.onrejectionhandled = e => console.log('handled', e.reason, e.promise);
let promise = Promise.reject(42);
// => unhandled 42 [object Promise]
setTimeout(() => promise.catch(() => {}), 1e3);
// => handled 42 [object Promise]
Modules es.symbol
, es.symbol.async-iterator
, esnext.symbol.description
, es.symbol.has-instance
, es.symbol.is-concat-spreadable
, es.symbol.iterator
, es.symbol.match
, es.symbol.replace
, es.symbol.search
, es.symbol.species
, es.symbol.split
, es.symbol.to-primitive
, es.symbol.to-string-tag
, es.symbol.unscopables
, es.math.to-string-tag
, es.json.to-string-tag
.
class Symbol {
constructor(description?): symbol;
get description: string | void;
static asyncIterator: @@asyncIterator;
static hasInstance: @@hasInstance;
static isConcatSpreadable: @@isConcatSpreadable;
static iterator: @@iterator;
static match: @@match;
static replace: @@replace;
static search: @@search;
static species: @@species;
static split: @@split;
static toPrimitive: @@toPrimitive;
static toStringTag: @@toStringTag;
static unscopables: @@unscopables;
static for(key: string): symbol;
static keyFor(sym: symbol): string;
static useSimple(): void;
static useSetter(): void;
}
class Object {
static getOwnPropertySymbols(object: any): Array<symbol>;
}
Also wrapped some methods for correct work with Symbol
polyfill.
class Object {
static create(prototype: Object | null, properties?: { [property: PropertyKey]: PropertyDescriptor }): Object;
static defineProperties(object: Object, properties: { [property: PropertyKey]: PropertyDescriptor })): Object;
static defineProperty(object: Object, property: PropertyKey, attributes: PropertyDescriptor): Object;
static getOwnPropertyDescriptor(object: any, property: PropertyKey): PropertyDescriptor | void;
static getOwnPropertyNames(object: any): Array<string>;
propertyIsEnumerable(key: PropertyKey): boolean;
}
namespace JSON {
stringify(target: any, replacer?: Function | Array, space?: string | number): string | void;
}
core-js(-pure)/es|features/symbol
core-js(-pure)/es|features/symbol/async-iterator
core-js/es|features/symbol/description
core-js(-pure)/es|features/symbol/has-instance
core-js(-pure)/es|features/symbol/is-concat-spreadable
core-js(-pure)/es|features/symbol/iterator
core-js(-pure)/es|features/symbol/match
core-js(-pure)/es|features/symbol/replace
core-js(-pure)/es|features/symbol/search
core-js(-pure)/es|features/symbol/species
core-js(-pure)/es|features/symbol/split
core-js(-pure)/es|features/symbol/to-primitive
core-js(-pure)/es|features/symbol/to-string-tag
core-js(-pure)/es|features/symbol/unscopables
core-js(-pure)/es|features/symbol/for
core-js(-pure)/es|features/symbol/key-for
core-js(-pure)/es|features/object/get-own-property-symbols
core-js(-pure)/es|features/math/to-string-tag
core-js(-pure)/es|features/json/to-string-tag
let Person = (() => {
let NAME = Symbol('name');
return class {
constructor(name) {
this[NAME] = name;
}
getName() {
return this[NAME];
}
}
})();
let person = new Person('Vasya');
console.log(person.getName()); // => 'Vasya'
console.log(person['name']); // => undefined
console.log(person[Symbol('name')]); // => undefined, symbols are uniq
for (let key in person) console.log(key); // => nothing, symbols are not enumerable
Symbol.for
& Symbol.keyFor
example:
let symbol = Symbol.for('key');
symbol === Symbol.for('key'); // true
Symbol.keyFor(symbol); // 'key'
Example with methods for getting own object keys:
let object = { a: 1 };
Object.defineProperty(object, 'b', { value: 2 });
object[Symbol('c')] = 3;
Object.keys(object); // => ['a']
Object.getOwnPropertyNames(object); // => ['a', 'b']
Object.getOwnPropertySymbols(object); // => [Symbol(c)]
Reflect.ownKeys(object); // => ['a', 'b', Symbol(c)]
Symbol('foo').description; // => 'foo'
Symbol().description; // => undefined
- We can't add new primitive type,
Symbol
returns object. Symbol.for
andSymbol.keyFor
can't be shimmed cross-realm.- By default, to hide the keys,
Symbol
polyfill defines setter inObject.prototype
. For this reason, uncontrolled creation of symbols can cause memory leak and thein
operator is not working correctly withSymbol
polyfill:Symbol() in {} // => true
.
You can disable defining setters in Object.prototype
. Example:
Symbol.useSimple();
let symbol1 = Symbol('symbol1');
let object1 = {};
object1[symbol1] = true;
for (let key in object1) console.log(key); // => 'Symbol(symbol1)_t.qamkg9f3q', w/o native Symbol
Symbol.useSetter();
let symbol2 = Symbol('symbol2');
let object2 = {};
object2[symbol2] = true;
for (let key in object2) console.log(key); // nothing
- Currently,
core-js
not adds setters toObject.prototype
for well-known symbols for correct work something likeSymbol.iterator in foo
. It can cause problems with their enumerability. - Some problems possible with environment exotic objects (for example, IE
localStorage
).
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).
Module es.map
.
class Map {
constructor(iterable?: Iterable<[key, value]>): Map;
clear(): void;
delete(key: any): boolean;
forEach(callbackfn: (value: any, key: any, target: any) => void, thisArg: any): void;
get(key: any): any;
has(key: any): boolean;
set(key: any, val: any): this;
values(): Iterator<value>;
keys(): Iterator<key>;
entries(): Iterator<[key, value]>;
@@iterator(): Iterator<[key, value]>;
get size: number;
}
core-js(-pure)/es|features/map
let array = [1];
let map = new Map([['a', 1], [42, 2]]);
map.set(array, 3).set(true, 4);
console.log(map.size); // => 4
console.log(map.has(array)); // => true
console.log(map.has([1])); // => false
console.log(map.get(array)); // => 3
map.forEach((val, key) => {
console.log(val); // => 1, 2, 3, 4
console.log(key); // => 'a', 42, [1], true
});
map.delete(array);
console.log(map.size); // => 3
console.log(map.get(array)); // => undefined
console.log(Array.from(map)); // => [['a', 1], [42, 2], [true, 4]]
let map = new Map([['a', 1], ['b', 2], ['c', 3]]);
for (let [key, value] of map) {
console.log(key); // => 'a', 'b', 'c'
console.log(value); // => 1, 2, 3
}
for (let value of map.values()) console.log(value); // => 1, 2, 3
for (let key of map.keys()) console.log(key); // => 'a', 'b', 'c'
for (let [key, value] of map.entries()) {
console.log(key); // => 'a', 'b', 'c'
console.log(value); // => 1, 2, 3
}
Module es.set
.
class Set {
constructor(iterable?: Iterable<value>): Set;
add(key: any): this;
clear(): void;
delete(key: any): boolean;
forEach((value: any, key: any, target: any) => void, thisArg: any): void;
has(key: any): boolean;
values(): Iterator<value>;
keys(): Iterator<value>;
entries(): Iterator<[value, value]>;
@@iterator(): Iterator<value>;
get size: number;
}
core-js(-pure)/es|features/set
let 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(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']
let set = new Set([1, 2, 3, 2, 1]);
for (let value of set) console.log(value); // => 1, 2, 3
for (let value of set.values()) console.log(value); // => 1, 2, 3
for (let key of set.keys()) console.log(key); // => 1, 2, 3
for (let [key, value] of set.entries()) {
console.log(key); // => 1, 2, 3
console.log(value); // => 1, 2, 3
}
Module es.weak-map
.
class WeakMap {
constructor(iterable?: Iterable<[key, value]>): WeakMap;
delete(key: Object): boolean;
get(key: Object): any;
has(key: Object): boolean;
set(key: Object, val: any): this;
}
core-js(-pure)/es|features/weak-map
let a = [1];
let b = [2];
let c = [3];
let weakmap = new WeakMap([[a, 1], [b, 2]]);
weakmap.set(c, 3).set(b, 4);
console.log(weakmap.has(a)); // => true
console.log(weakmap.has([1])); // => false
console.log(weakmap.get(a)); // => 1
weakmap.delete(a);
console.log(weakmap.get(a)); // => undefined
// Private properties store:
let Person = (() => {
let names = new WeakMap;
return class {
constructor(name) {
names.set(this, name);
}
getName() {
return names.get(this);
}
}
})();
let person = new Person('Vasya');
console.log(person.getName()); // => 'Vasya'
for (let key in person) console.log(key); // => only 'getName'
Module es.weak-set
.
class WeakSet {
constructor(iterable?: Iterable<value>): WeakSet;
add(key: Object): this;
delete(key: Object): boolean;
has(key: Object): boolean;
}
core-js(-pure)/es|features/weak-set
let a = [1];
let b = [2];
let c = [3];
let weakset = new WeakSet([a, b, a]);
weakset.add(c).add(b).add(c);
console.log(weakset.has(b)); // => true
console.log(weakset.has([2])); // => false
weakset.delete(b);
console.log(weakset.has(b)); // => false
- 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.
Implementations and fixes for 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 es.array-buffer.constructor
, es.array-buffer.is-view
, es.array-buffer.slice
, es.data-view
, es.typed-array.int8-array
, es.typed-array.uint8-array
, es.typed-array.uint8-clamped-array
, es.typed-array.int16-array
, es.typed-array.uint16-array
, es.typed-array.int32-array
, es.typed-array.uint32-array
, es.typed-array.float32-array
, es.typed-array.float64-array
, es.typed-array.copy-within
, es.typed-array.every
, es.typed-array.fill
, es.typed-array.filter
, es.typed-array.find
, es.typed-array.find-index
, es.typed-array.for-each
, es.typed-array.from
, es.typed-array.includes
, es.typed-array.index-of
, es.typed-array.iterator
, es.typed-array.last-index-of
, es.typed-array.map
, es.typed-array.of
, es.typed-array.reduce
, es.typed-array.reduce-right
, es.typed-array.reverse
, es.typed-array.set
, es.typed-array.slice
, es.typed-array.some
, es.typed-array.sort
, es.typed-array.subarray
, es.typed-array.to-locale-string
and es.typed-array.to-string
.
class ArrayBuffer {
constructor(length: any): ArrayBuffer;
slice(start: any, end: any): ArrayBuffer;
get byteLength: number;
static isView(arg: any): boolean;
}
class DataView {
constructor(buffer: ArrayBuffer, byteOffset?: number, byteLength?: number): DataView;
getInt8(offset: any): int8;
getUint8(offset: any): uint8
getInt16(offset: any, littleEndian?: boolean = false): int16;
getUint16(offset: any, littleEndian?: boolean = false): uint16;
getInt32(offset: any, littleEndian?: boolean = false): int32;
getUint32(offset: any, littleEndian?: boolean = false): uint32;
getFloat32(offset: any, littleEndian?: boolean = false): float32;
getFloat64(offset: any, littleEndian?: boolean = false): float64;
setInt8(offset: any, value: any): void;
setUint8(offset: any, value: any): void;
setInt16(offset: any, value: any, littleEndian?: boolean = false): void;
setUint16(offset: any, value: any, littleEndian?: boolean = false): void;
setInt32(offset: any, value: any, littleEndian?: boolean = false): void;
setUint32(offset: any, value: any, littleEndian?: boolean = false): void;
setFloat32(offset: any, value: any, littleEndian?: boolean = false): void;
setFloat64(offset: any, value: any, littleEndian?: boolean = false): void;
get buffer: ArrayBuffer;
get byteLength: number;
get byteOffset: number;
}
class [
Int8Array,
Uint8Array,
Uint8ClampedArray,
Int16Array,
Uint16Array,
Int32Array,
Uint32Array,
Float32Array,
Float64Array,
] {
constructor(length: number): %TypedArray%;
constructor(object: %TypedArray% | Iterable | ArrayLike): %TypedArray%;
constructor(buffer: ArrayBuffer, byteOffset?: number, length?: number): %TypedArray%;
copyWithin(target: number, start: number, end?: number): this;
every(callbackfn: (value: number, index: number, target: any) => boolean, thisArg?: any): boolean;
fill(value: number, start?: number, end?: number): this;
filter(callbackfn: (value: number, index: number, target: any) => boolean, thisArg?: any): %TypedArray%;
find(callbackfn: (value: number, index: number, target: any) => boolean), thisArg?: any): any;
findIndex(callbackfn: (value: number, index: number, target: any) => boolean, thisArg?: any): number;
forEach(callbackfn: (value: number, index: number, target: any) => void, thisArg?: any): void;
includes(searchElement: any, from?: number): boolean;
indexOf(searchElement: any, from?: number): number;
join(separator: string = ','): string;
lastIndexOf(searchElement: any, from?: number): number;
map(mapFn: (value: number, index: number, target: any) => number, thisArg?: any): %TypedArray%;
reduce(callbackfn: (memo: any, value: number, index: number, target: any) => any, initialValue?: any): any;
reduceRight(callbackfn: (memo: any, value: number, index: number, target: any) => any, initialValue?: any): any;
reverse(): this;
set(array: ArrayLike, offset?: number): void;
slice(start?: number, end?: number): %TypedArray%;
some(callbackfn: (value: number, index: number, target: any) => boolean, thisArg?: any): boolean;
sort(comparefn?: (a: number, b: number) => number): this;
subarray(begin?: number, end?: number): %TypedArray%;
toString(): string;
toLocaleString(): string;
values(): Iterator<value>;
keys(): Iterator<index>;
entries(): Iterator<[index, value]>;
@@iterator(): Iterator<value>;
get buffer: ArrayBuffer;
get byteLength: number;
get byteOffset: number;
get length: number;
BYTES_PER_ELEMENT: number;
static from(items: Iterable | ArrayLike, mapFn?: (value: any, index: number) => any, thisArg?: any): %TypedArray%;
static of(...args: Array<mixed>): %TypedArray%;
static BYTES_PER_ELEMENT: number;
}
core-js/es|features/array-buffer
core-js/es|features/array-buffer/constructor
core-js/es|features/array-buffer/is-view
core-js/es|features/array-buffer/slice
core-js/es|features/data-view
core-js/es|features/typed-array
core-js/es|features/typed-array/int8-array
core-js/es|features/typed-array/uint8-array
core-js/es|features/typed-array/uint8-clamped-array
core-js/es|features/typed-array/int16-array
core-js/es|features/typed-array/uint16-array
core-js/es|features/typed-array/int32-array
core-js/es|features/typed-array/uint32-array
core-js/es|features/typed-array/float32-array
core-js/es|features/typed-array/float64-array
core-js/es|features/typed-array/copy-within
core-js/es|features/typed-array/entries
core-js/es|features/typed-array/every
core-js/es|features/typed-array/fill
core-js/es|features/typed-array/filter
core-js/es|features/typed-array/find
core-js/es|features/typed-array/find-index
core-js/es|features/typed-array/for-each
core-js/es|features/typed-array/from
core-js/es|features/typed-array/includes
core-js/es|features/typed-array/index-of
core-js/es|features/typed-array/iterator
core-js/es|features/typed-array/join
core-js/es|features/typed-array/keys
core-js/es|features/typed-array/last-index-of
core-js/es|features/typed-array/map
core-js/es|features/typed-array/of
core-js/es|features/typed-array/reduce
core-js/es|features/typed-array/reduce-right
core-js/es|features/typed-array/reverse
core-js/es|features/typed-array/set
core-js/es|features/typed-array/slice
core-js/es|features/typed-array/some
core-js/es|features/typed-array/sort
core-js/es|features/typed-array/subarray
core-js/es|features/typed-array/to-locale-string
core-js/es|features/typed-array/to-string
core-js/es|features/typed-array/values
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]
let buffer = new ArrayBuffer(8);
let 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]
let typed = new Uint8Array([1, 2, 3]);
let a = typed.slice(1); // => [2, 3]
typed.buffer === a.buffer; // => false
let 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 (let value of typed) console.log(value); // => 1, 2, 3
for (let value of typed.values()) console.log(value); // => 1, 2, 3
for (let key of typed.keys()) console.log(key); // => 0, 1, 2
for (let [key, value] of typed.entries()) {
console.log(key); // => 0, 1, 2
console.log(value); // => 1, 2, 3
}
- Polyfills of Typed Arrays constructors work completely how should work by the spec, but because of internal usage of getters / setters on each instance, are slow and consumes significant memory. However, polyfills of Typed Arrays constructors required mainly for old IE, all modern engines have native Typed Arrays constructors and require only fixes of constructors and polyfills of methods.
Modules es.reflect.apply
, es.reflect.construct
, es.reflect.define-property
, es.reflect.delete-property
, es.reflect.get
, es.reflect.get-own-property-descriptor
, es.reflect.get-prototype-of
, es.reflect.has
, es.reflect.is-extensible
, es.reflect.own-keys
, es.reflect.prevent-extensions
, es.reflect.set
, es.reflect.set-prototype-of
.
namespace Reflect {
apply(target: Function, thisArgument: any, argumentsList: Array<mixed>): any;
construct(target: Function, argumentsList: Array<mixed>, newTarget?: Function): Object;
defineProperty(target: Object, propertyKey: PropertyKey, attributes: PropertyDescriptor): boolean;
deleteProperty(target: Object, propertyKey: PropertyKey): boolean;
get(target: Object, propertyKey: PropertyKey, receiver?: any): any;
getOwnPropertyDescriptor(target: Object, propertyKey: PropertyKey): PropertyDescriptor | void;
getPrototypeOf(target: Object): Object | null;
has(target: Object, propertyKey: PropertyKey): boolean;
isExtensible(target: Object): boolean;
ownKeys(target: Object): Array<string | symbol>;
preventExtensions(target: Object): boolean;
set(target: Object, propertyKey: PropertyKey, V: any, receiver?: any): boolean;
setPrototypeOf(target: Object, proto: Object | null): boolean; // required __proto__ - IE11+
}
core-js(-pure)/es|features/reflect
core-js(-pure)/es|features/reflect/apply
core-js(-pure)/es|features/reflect/construct
core-js(-pure)/es|features/reflect/define-property
core-js(-pure)/es|features/reflect/delete-property
core-js(-pure)/es|features/reflect/get
core-js(-pure)/es|features/reflect/get-own-property-descriptor
core-js(-pure)/es|features/reflect/get-prototype-of
core-js(-pure)/es|features/reflect/has
core-js(-pure)/es|features/reflect/is-extensible
core-js(-pure)/es|features/reflect/own-keys
core-js(-pure)/es|features/reflect/prevent-extensions
core-js(-pure)/es|features/reflect/set
core-js(-pure)/es|features/reflect/set-prototype-of
let object = { a: 1 };
Object.defineProperty(object, 'b', { value: 2 });
object[Symbol('c')] = 3;
Reflect.ownKeys(object); // => ['a', 'b', Symbol(c)]
function C(a, b) {
this.c = a + b;
}
let instance = Reflect.construct(C, [20, 22]);
instance.c; // => 42
The TC39 process.
core-js/stage/4
entry point contains only stage 4 proposals, core-js/stage/3
- stage 3 and stage 4, etc.
core-js(-pure)/stage/4
None.
core-js(-pure)/stage/3
Array#flat
andArray#flatMap
proposal - modulesesnext.array.flat
andesnext.array.flat-map
class Array {
flat(depthArg?: number = 1): Array<mixed>;
flatMap(mapFn: (value: any, index: number, target: any) => any, thisArg: any): Array<mixed>;
}
core-js/proposals/array-flat-and-flat-map
core-js(-pure)/features/array/flat
core-js(-pure)/features/array/flat-map
core-js(-pure)/features/array/virtual/flat
core-js(-pure)/features/array/virtual/flat-map
[1, [2, 3], [4, 5]].flat(); // => [1, 2, 3, 4, 5]
[1, [2, [3, [4]]], 5].flat(); // => [1, 2, [3, [4]], 5]
[1, [2, [3, [4]]], 5].flat(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]
Object.fromEntries
, proposal, moduleesnext.object.from-entries
class Object {
static fromEntries(iterable: Iterable<[key, value]>): Object;
}
core-js/proposals/object-from-entries
core-js(-pure)/features/object/from-entries
const map = new Map([['a', 1], ['b', 2]]);
Object.fromEntries(map); // => { a: 1, b: 2 }
class Unit {
constructor(id) {
this.id = id;
}
toString() {
return `unit${ this.id }`;
}
}
const units = new Set([new Unit(101), new Unit(102)]);
Object.fromEntries(units.entries()); // => { unit101: Unit { id: 101 }, unit102: Unit { id: 102 } }
String#matchAll
proposal - moduleesnext.string.match-all
class String {
matchAll(regexp: RegExp): Iterator;
}
core-js/proposals/string-match-all
core-js(-pure)/features/string/match-all
core-js(-pure)/features/string/virtual/match-all
for (let [_, d, D] of '1111a2b3cccc'.matchAll(/(\d)(\D)/g)) {
console.log(d, D); // => 1 a, 2 b, 3 c
}
String#trimLeft
,String#trimRight
/String#trimStart
,String#trimEnd
proposal - modulesesnext.string.trim-left
,esnext.string.trim-right
class String {
trimLeft(): string;
trimRight(): string;
trimStart(): string;
trimEnd(): string;
}
core-js/proposals/string-trim-start-end
core-js(-pure)/features/string/trim-start
core-js(-pure)/features/string/trim-end
core-js(-pure)/features/string/trim-left
core-js(-pure)/features/string/trim-right
core-js(-pure)/features/string/virtual/trim-start
core-js(-pure)/features/string/virtual/trim-end
core-js(-pure)/features/string/virtual/trim-left
core-js(-pure)/features/string/virtual/trim-right
' hello '.trimLeft(); // => 'hello '
' hello '.trimRight(); // => ' hello'
globalThis
proposal - moduleesnext.global-this
.
let globalThis: Object;
core-js/proposals/global-this
core-js(-pure)/features/global-this
globalThis.Array === Array; // => true
core-js(-pure)/stage/2
- New
Set
methods proposal - modulesesnext.set.difference
,esnext.set.intersection
,esnext.set.symmetric-difference
,esnext.set.union
class Set {
difference(iterable: Iterable<mixed>): Set;
intersection(iterable: Iterable<mixed>): Set;
symmetric-difference(iterable: Iterable<mixed>): Set;
union(iterable: Iterable<mixed>): Set;
}
core-js/proposals/set-methods
core-js(-pure)/features/set/difference
core-js(-pure)/features/set/intersection
core-js(-pure)/features/set/symmetric-difference
core-js(-pure)/features/set/union
new Set([1, 2, 3]).union([3, 4, 5]); // => Set {1, 2, 3, 4, 5}
new Set([1, 2, 3]).intersection([3, 4, 5]); // => Set {3}
new Set([1, 2, 3]).difference([3, 4, 5]); // => Set {1, 2}
new Set([1, 2, 3]).symmetricDifference([3, 4, 5]); // => Set {1, 2, 4, 5}
core-js(-pure)/stage/1
- Getting last item from
Array
proposal - modulesesnext.array.last-item
andesnext.array.last-index
class Array {
get lastItem: value;
set lastItem(value);
get lastIndex: uint;
}
core-js/proposals/array-last
core-js/features/array/last-item
core-js/features/array/last-index
[1, 2, 3].lastItem; // => 3
[1, 2, 3].lastIndex; // => 2
const array = [1, 2, 3];
array.lastItem = 4;
array; // => [1, 2, 4]
String#replaceAll
proposal - moduleesnext.string.replace-all
class String {
replaceAll(searchString: string, replaceString: string): string;
}
core-js/proposals/string-replace-all
core-js/features/string/replace-all
'Test abc test test abc test.'.replaceAll('abc', 'foo'); // -> 'Test foo test test foo test.'
Promise.allSettled
proposal - moduleesnext.promise.all-settled
class Promise {
static allSettled(iterable): promise;
}
core-js/proposals/promise-all-settled
core-js(-pure)/features/promise/all-settled
Promise.allSettled([
Promise.resolve(1),
Promise.reject(2),
Promise.resolve(3),
]).then(console.log); // => [{ value: 1, status: 'fulfilled' }, { reason: 2, status: 'rejected' }, { value: 3, status: 'fulfilled' }]
Promise.try
proposal - moduleesnext.promise.try
class Promise {
static try(callbackfn: Function): promise;
}
core-js/proposals/promise-try
core-js(-pure)/features/promise/try
Promise.try(() => 42).then(it => console.log(`Promise, resolved as ${it}`));
Promise.try(() => { throw 42; }).catch(it => console.log(`Promise, rejected as ${it}`));
- New collections methods proposals:
- New
Set
andMap
methods proposal - modulesesnext.set.add-all
,esnext.set.delete-all
,esnext.set.every
,esnext.set.filter
,esnext.set.find
,esnext.set.join
,esnext.set.map
,esnext.set.reduce
,esnext.set.some
,esnext.map.delete-all
,esnext.map.every
,esnext.map.filter
,esnext.map.find
,esnext.map.find-key
,esnext.map.group-by
,esnext.map.includes
,esnext.map.key-by
,esnext.map.key-of
,esnext.map.map-keys
,esnext.map.map-values
,esnext.map.merge
,esnext.map.reduce
,esnext.map.some
,esnext.weak-set.add-all
,esnext.weak-set.delete-all
,esnext.weak-map.delete-all
.of
and.from
methods on collection constructors proposal - modulesesnext.set.of
,esnext.set.from
,esnext.map.of
,esnext.map.from
,esnext.weak-set.of
,esnext.weak-set.from
,esnext.weak-map.of
,esnext.weak-map.from
class Set {
static of(...args: Array<mixed>): Set;
static from(iterable: Iterable<mixed>, mapFn?: (value: any, index: number) => any, thisArg?: any): Set;
addAll(...args: Array<mixed>): this;
deleteAll(...args: Array<mixed>): boolean;
every(callbackfn: (value: any, key: any, target: any) => boolean, thisArg?: any): boolean;
filter(callbackfn: (value: any, key: any, target: any) => boolean, thisArg?: any): Set;
find(callbackfn: (value: any, key: any, target: any) => boolean), thisArg?: any): any;
join(separator: string = ','): string;
map(callbackfn: (value: any, key: any, target: any) => boolean, thisArg?: any): Set;
reduce(callbackfn: (memo: any, value: any, key: any, target: any) => any, initialValue?: any): any;
some(callbackfn: (value: any, key: any, target: any) => boolean, thisArg?: any): boolean;
}
class Map {
static groupBy(iterable: Iterable<mixed>, callbackfn?: (value: any) => any): Map;
static of(...args: Array<[key, value]>): Map;
static from(iterable: Iterable<mixed>, mapFn?: (value: any, index: number) => [key: any, value: any], thisArg?: any): Map;
static keyBy(iterable: Iterable<mixed>, callbackfn?: (value: any) => any): Map;
deleteAll(...args: Array<mixed>): boolean;
every(callbackfn: (value: any, key: any, target: any) => boolean, thisArg?: any): boolean;
filter(callbackfn: (value: any, key: any, target: any) => boolean, thisArg?: any): Map;
find(callbackfn: (value: any, key: any, target: any) => boolean), thisArg?: any): any;
findKey(callbackfn: (value: any, key: any, target: any) => boolean), thisArg?: any): any;
includes(searchElement: any): boolean;
keyOf(searchElement: any): any;
mapKeys(mapFn: (value: any, index: number, target: any) => any, thisArg?: any): Map;
mapValues(mapFn: (value: any, index: number, target: any) => any, thisArg?: any): Map;
merge(iterable: Iterable<mixed>): Map;
reduce(callbackfn: (memo: any, value: any, key: any, target: any) => any, initialValue?: any): any;
some(callbackfn: (value: any, key: any, target: any) => boolean, thisArg?: any): boolean;
}
class WeakSet {
static of(...args: Array<mixed>): WeakSet;
static from(iterable: Iterable<mixed>, mapFn?: (value: any, index: number) => Object, thisArg?: any): WeakSet;
addAll(...args: Array<mixed>): this;
deleteAll(...args: Array<mixed>): boolean;
}
class WeakMap {
static of(...args: Array<[key, value]>): WeakMap;
static from(iterable: Iterable<mixed>, mapFn?: (value: any, index: number) => [key: Object, value: any], thisArg?: any): WeakMap;
deleteAll(...args: Array<mixed>): boolean;
}
core-js/proposals/collection-methods
core-js/proposals/collection-of-from
core-js(-pure)/features/set/add-all
core-js(-pure)/features/set/delete-all
core-js(-pure)/features/set/every
core-js(-pure)/features/set/filter
core-js(-pure)/features/set/find
core-js(-pure)/features/set/from
core-js(-pure)/features/set/join
core-js(-pure)/features/set/map
core-js(-pure)/features/set/of
core-js(-pure)/features/set/reduce
core-js(-pure)/features/set/some
core-js(-pure)/features/map/delete-all
core-js(-pure)/features/map/every
core-js(-pure)/features/map/filter
core-js(-pure)/features/map/find
core-js(-pure)/features/map/find-key
core-js(-pure)/features/map/from
core-js(-pure)/features/map/group-by
core-js(-pure)/features/map/includes
core-js(-pure)/features/map/key-by
core-js(-pure)/features/map/key-of
core-js(-pure)/features/map/map-keys
core-js(-pure)/features/map/map-values
core-js(-pure)/features/map/merge
core-js(-pure)/features/map/of
core-js(-pure)/features/map/reduce
core-js(-pure)/features/map/some
core-js(-pure)/features/weak-set/add-all
core-js(-pure)/features/weak-set/delete-all
core-js(-pure)/features/weak-set/of
core-js(-pure)/features/weak-set/from
core-js(-pure)/features/weak-map/delete-all
core-js(-pure)/features/weak-map/of
core-js(-pure)/features/weak-map/from
Set.of(1, 2, 3, 2, 1); // => Set {1, 2, 3}
Map.from([[1, 2], [3, 4]], ([key, value]) => [key ** 2, value ** 2]); // => Map {1: 4, 9: 16}
compositeKey
andcompositeSymbol
methods from richer keys proposal - modulesesnext.composite-key
andesnext.composite-symbol
function compositeKey(...args: Array<mixed>): object;
function compositeSymbol(...args: Array<mixed>): symbol;
core-js/proposals/richer-keys
core-js(-pure)/features/composite-key
core-js(-pure)/features/composite-symbol
// returns a symbol
const symbol = compositeSymbol({});
console.log(typeof symbol); // => 'symbol'
// works the same, but returns a plain frozen object without a prototype
const key = compositeKey({});
console.log(typeof key); // => 'object'
console.log({}.toString.call(key)); // => '[object Object]'
console.log(Object.getPrototypeOf(key)); // => null
console.log(Object.isFrozen(key)); // => true
const a = ['a'];
const b = ['b'];
const c = ['c'];
console.log(compositeSymbol(a) === compositeSymbol(a)); // => true
console.log(compositeSymbol(a) !== compositeSymbol(['a'])); // => true
console.log(compositeSymbol(a, 1) === compositeSymbol(a, 1)); // => true
console.log(compositeSymbol(a, b) !== compositeSymbol(b, a)); // => true
console.log(compositeSymbol(a, b, c) === compositeSymbol(a, b, c)); // => true
console.log(compositeSymbol(1, a) === compositeSymbol(1, a)); // => true
console.log(compositeSymbol(1, a, 2, b) === compositeSymbol(1, a, 2, b)); // => true
console.log(compositeSymbol(a, a) === compositeSymbol(a, a)); // => true
Observable
proposal - modulesesnext.observable
andesnext.symbol.observable
class Observable {
constructor(subscriber: Function): Observable;
subscribe(observer: Function | { next?: Function, error?: Function, complete?: Function }): Subscription;
@@observable(): this;
static of(...items: Aray<mixed>): Observable;
static from(x: Observable | Iterable): Observable;
static get @@species: this;
}
class Symbol {
static observable: @@observable;
}
core-js/proposals/observable
core-js(-pure)/features/observable
core-js(-pure)/features/symbol/observable
new Observable(observer => {
observer.next('hello');
observer.next('world');
observer.complete();
}).subscribe({
next(it) { console.log(it); },
complete() { console.log('!'); }
});
Math
extensions proposal - modulesesnext.math.clamp
,esnext.math.DEG_PER_RAD
,esnext.math.degrees
,esnext.math.fscale
,esnext.math.RAD_PER_DEG
,esnext.math.radians
andesnext.math.scale
namespace Math {
DEG_PER_RAD: number;
RAD_PER_DEG: number;
clamp(x: number, lower: number, upper: number): number;
degrees(radians: number): number;
fscale(x: number, inLow: number, inHigh: number, outLow: number, outHigh: number): number;
radians(degrees: number): number;
scale(x: number, inLow: number, inHigh: number, outLow: number, outHigh: number): number;
}
core-js/proposals/math-extensions
core-js(-pure)/features/math/clamp
core-js(-pure)/features/math/deg-per-rad
core-js(-pure)/features/math/degrees
core-js(-pure)/features/math/fscale
core-js(-pure)/features/math/rad-per-deg
core-js(-pure)/features/math/radians
core-js(-pure)/features/math/scale
Math.signbit
proposal - moduleesnext.math.signbit
namespace Math {
signbit(x: number): boolean;
}
core-js/proposals/math-signbit
core-js(-pure)/features/math/signbit
Math.signbit(NaN); // => NaN
Math.signbit(1); // => true
Math.signbit(-1); // => false
Math.signbit(0); // => true
Math.signbit(-0); // => false
Number.fromString
proposal - moduleesnext.number.from-string
class Number {
fromString(string: string, radix: number): number;
}
core-js/proposals/number-from-string
core-js(-pure)/features/number/from-string
String#codePoints
proposal - moduleesnext.string.code-points
class String {
codePoints(): Iterator<codePoint, position>;
}
core-js/proposals/string-code-points
core-js(-pure)/features/string/code-points
for (let { codePoint, position } of 'qwe'.codePoints()) {
console.log(codePoint); // => 113, 119, 101
console.log(position); // => 0, 1, 2
}
- Seeded pseudo-random numbers proposal - module
esnext.math.seeded-prng
class Math {
seededPRNG({ seed: number }): Iterator<number>;
}
core-js/proposals/seeded-random
core-js(-pure)/features/math/seeded-prng
for (let x of Math.seededPRNG({ seed: 42 })) {
console.log(x); // => 0.16461519912315087, 0.2203933906000046, 0.8249682894209105
if (x > .8) break;
}
Symbol.patternMatch
for pattern matching proposal - moduleesnext.symbol.pattern-match
.
class Symbol {
static patternMatch: @@patternMatch;
}
core-js/proposals/pattern-matching
core-js(-pure)/features/symbol/pattern-match
Symbol.dispose
forusing
statement proposal - moduleesnext.symbol.dispose
.
class Symbol {
static dispose: @@dispose;
}
core-js/proposals/using-statement
core-js(-pure)/features/symbol/dispose
core-js(-pure)/stage/0
String#at
proposal - moduleesnext.string.at
class String {
at(index: number): string;
}
core-js/proposals/string-at
core-js(-pure)/features/string/at
core-js(-pure)/features/string/virtual/at
'a๐ ฎทb'.at(1); // => '๐ ฎท'
'a๐ ฎทb'.at(1).length; // => 2
- Efficient 64 bit arithmetic proposal - modules
esnext.math.iaddh
,esnext.math.isubh
,esnext.math.imulh
andesnext.math.umulh
namespace Math {
iaddh(lo0: number, hi0: number, lo1: number, hi1: number): number;
isubh(lo0: number, hi0: number, lo1: number, hi1: number): number;
imulh(a: number, b: number): number;
umulh(a: number, b: number): number;
}
core-js/proposals/efficient-64-bit-arithmetic
core-js(-pure)/features/math/iaddh
core-js(-pure)/features/math/isubh
core-js(-pure)/features/math/imulh
core-js(-pure)/features/math/umulh
core-js(-pure)/stage/pre
Reflect
metadata proposal - modulesesnext.reflect.define-metadata
,esnext.reflect.delete-metadata
,esnext.reflect.get-metadata
,esnext.reflect.get-metadata-keys
,esnext.reflect.get-own-metadata
,esnext.reflect.get-own-metadata-keys
,esnext.reflect.has-metadata
,esnext.reflect.has-own-metadata
andesnext.reflect.metadata
.
namespace Reflect {
defineMetadata(metadataKey: any, metadataValue: any, target: Object, propertyKey?: PropertyKey): void;
getMetadata(metadataKey: any, target: Object, propertyKey?: PropertyKey): any;
getOwnMetadata(metadataKey: any, target: Object, propertyKey?: PropertyKey): any;
hasMetadata(metadataKey: any, target: Object, propertyKey?: PropertyKey): boolean;
hasOwnMetadata(metadataKey: any, target: Object, propertyKey?: PropertyKey): boolean;
deleteMetadata(metadataKey: any, target: Object, propertyKey?: PropertyKey): boolean;
getMetadataKeys(target: Object, propertyKey?: PropertyKey): Array<mixed>;
getOwnMetadataKeys(target: Object, propertyKey?: PropertyKey): Array<mixed>;
metadata(metadataKey: any, metadataValue: any): decorator(target: Object, targetKey?: PropertyKey) => void;
}
core-js/proposals/reflect-metadata
core-js(-pure)/features/reflect/define-metadata
core-js(-pure)/features/reflect/delete-metadata
core-js(-pure)/features/reflect/get-metadata
core-js(-pure)/features/reflect/get-metadata-keys
core-js(-pure)/features/reflect/get-own-metadata
core-js(-pure)/features/reflect/get-own-metadata-keys
core-js(-pure)/features/reflect/has-metadata
core-js(-pure)/features/reflect/has-own-metadata
core-js(-pure)/features/reflect/metadata
let object = {};
Reflect.defineMetadata('foo', 'bar', object);
Reflect.ownKeys(object); // => []
Reflect.getOwnMetadataKeys(object); // => ['foo']
Reflect.getOwnMetadata('foo', object); // => 'bar'
core-js(-pure)/web
Module web.timers
. Additional arguments fix for IE9-.
function setTimeout(callback: any, time: any, ...args: Array<mixed>): number;
function setInterval(callback: any, time: any, ...args: Array<mixed>): number;
core-js(-pure)/web/timers
core-js(-pure)/features/set-timeout
core-js(-pure)/features/set-interval
// Before:
setTimeout(log.bind(null, 42), 1000);
// After:
setTimeout(log, 1000, 42);
Module web.immediate
. setImmediate
proposal polyfill.
function setImmediate(callback: any, ...args: Array<mixed>): number;
function clearImmediate(id: number): void;
core-js(-pure)/web/immediate
core-js(-pure)/features/set-immediate
core-js(-pure)/features/clear-immediate
setImmediate((arg1, arg2) => {
console.log(arg1, arg2); // => Message will be displayed with minimum delay
}, 'Message will be displayed', 'with minimum delay');
clearImmediate(setImmediate(() => {
console.log('Message will not be displayed');
}));
Spec, module web.queue-microtask
function queueMicrotask(fn: Function): void;
core-js/web/queue-microtask
core-js(-pure)/features/queue-microtask
queueMicrotask(() => console.log('called as microtask'));
Some DOM collections should have iterable interface or should be inherited from Array
. That means they should have forEach
, keys
, values
, entries
and @@iterator
methods for iteration. So add them. Modules web.dom-collections.iterator
and web.dom-collections.for-each
.
class [
CSSRuleList,
CSSStyleDeclaration,
CSSValueList,
ClientRectList,
DOMRectList,
DOMStringList,
DataTransferItemList,
FileList,
HTMLAllCollection,
HTMLCollection,
HTMLFormElement,
HTMLSelectElement,
MediaList,
MimeTypeArray,
NamedNodeMap,
PaintRequestList,
Plugin,
PluginArray,
SVGLengthList,
SVGNumberList,
SVGPathSegList,
SVGPointList,
SVGStringList,
SVGTransformList,
SourceBufferList,
StyleSheetList,
TextTrackCueList,
TextTrackList,
TouchList,
] {
@@iterator(): Iterator<value>;
}
class [DOMTokenList, NodeList] {
entries(): Iterator<[key, value]>;
forEach(callbackfn: (value: any, index: number, target: any) => void, thisArg: any): void;
keys(): Iterator<key>;
values(): Iterator<value>;
@@iterator(): Iterator<value>;
}
core-js(-pure)/web/dom-collections
core-js(-pure)/features/dom-collections/iterator
core-js/features/dom-collections/for-each
for (let { id } of document.querySelectorAll('*')) {
if (id) console.log(id);
}
for (let [index, { id }] of document.querySelectorAll('*').entries()) {
if (id) console.log(index, id);
}
document.querySelectorAll('*').forEach(it => console.log(it.id));
Modules core.is-iterable
, core.get-iterator
, core.get-iterator-method
- helpers for check iterability / get iterator in the pure
version or, for example, for arguments
object:
function isIterable(value: any): boolean;
function getIterator(value: any): Object;
function getIteratorMethod(value: any): Function | void;
core-js-pure/features/is-iterable
core-js-pure/features/get-iterator
core-js-pure/features/get-iterator-method
import isIterable from 'core-js-pure/features/is-iterable';
import getIterator from 'core-js-pure/features/get-iterator';
import getIteratorMethod from 'core-js-pure/features/get-iterator-method';
let list = (function () {
return arguments;
})(1, 2, 3);
console.log(isIterable(list)); // true;
let iterator = getIterator(list);
console.log(iterator.next().value); // 1
console.log(iterator.next().value); // 2
console.log(iterator.next().value); // 3
console.log(iterator.next().value); // undefined
getIterator({}); // TypeError: [object Object] is not iterable!
let method = getIteratorMethod(list);
console.log(typeof method); // 'function'
let iterator = method.call(list);
console.log(iterator.next().value); // 1
console.log(iterator.next().value); // 2
console.log(iterator.next().value); // 3
console.log(iterator.next().value); // undefined
console.log(getIteratorMethod({})); // undefined
- ES
JSON
is missing now only in IE7- and never will it be added tocore-js
, if you need it in these old browsers, many implementations are available. - ES
String#normalize
is not a very useful feature, but this polyfill will be very large. If you need it, you can use unorm. - ES
Proxy
can't be polyfilled, but for Node.js / Chromium with additional flags you can try harmony-reflect for adapt old styleProxy
API to final ES2015 version. 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 incore-js
. Looking at a large number of requests it may be added in the future. Now you can use, for example, this polyfill.- ECMA-402
Intl
is missed because of size. You can use this polyfill.