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[![fundraising](https://opencollective.com/core-js/all/badge.svg?label=fundraising)](https://opencollective.com/core-js) [![PRs welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](https://github.com/zloirock/core-js/blob/master/CONTRIBUTING.md) [![version](https://img.shields.io/npm/v/core-js.svg)](https://www.npmjs.com/package/core-js) [![core-js downloads](https://img.shields.io/npm/dm/core-js.svg?label=npm%20i%20core-js)](https://npm-stat.com/charts.html?package=core-js&package=core-js-pure&package=core-js-compat&from=2014-11-18)

**I highly recommend reading this: [So, what's next?](https://github.com/zloirock/core-js/blob/master/docs/2023-02-14-so-whats-next.md)** --- > Modular standard library for JavaScript. Includes polyfills for [ECMAScript up to 2023](https://github.com/zloirock/core-js#ecmascript): [promises](https://github.com/zloirock/core-js#ecmascript-promise), [symbols](https://github.com/zloirock/core-js#ecmascript-symbol), [collections](https://github.com/zloirock/core-js#ecmascript-collections), iterators, [typed arrays](https://github.com/zloirock/core-js#ecmascript-typed-arrays), many other features, [ECMAScript proposals](https://github.com/zloirock/core-js#ecmascript-proposals), [some cross-platform WHATWG / W3C features and proposals](#web-standards) like [`URL`](https://github.com/zloirock/core-js#url-and-urlsearchparams). You can load only required features or use it without global namespace pollution. ## Raising funds `core-js` isn't backed by a company, so the future of this project depends on you. Become a sponsor or a backer if you are interested in `core-js`: [**Open Collective**](https://opencollective.com/core-js), [**Patreon**](https://patreon.com/zloirock), [**Boosty**](https://boosty.to/zloirock), **Bitcoin ( bc1qlea7544qtsmj2rayg0lthvza9fau63ux0fstcz )**, [**Alipay**](https://user-images.githubusercontent.com/2213682/219464783-c17ad329-17ce-4795-82a7-f609493345ed.png). ---

---

--- [*Example of usage*](https://tinyurl.com/2mknex43): ```js import 'core-js/actual'; Promise.resolve(42).then(it => console.log(it)); // => 42 Array.from(new Set([1, 2, 3]).union(new Set([3, 4, 5]))); // => [1, 2, 3, 4, 5] [1, 2].flatMap(it => [it, it]); // => [1, 1, 2, 2] (function * (i) { while (true) yield i++; })(1) .drop(1).take(5) .filter(it => it % 2) .map(it => it ** 2) .toArray(); // => [9, 25] structuredClone(new Set([1, 2, 3])); // => new Set([1, 2, 3]) ``` *You can load only required features*: ```js import 'core-js/actual/promise'; import 'core-js/actual/set'; import 'core-js/actual/iterator'; import 'core-js/actual/array/from'; import 'core-js/actual/array/flat-map'; import 'core-js/actual/structured-clone'; Promise.resolve(42).then(it => console.log(it)); // => 42 Array.from(new Set([1, 2, 3]).union(new Set([3, 4, 5]))); // => [1, 2, 3, 4, 5] [1, 2].flatMap(it => [it, it]); // => [1, 1, 2, 2] (function * (i) { while (true) yield i++; })(1) .drop(1).take(5) .filter(it => it % 2) .map(it => it ** 2) .toArray(); // => [9, 25] structuredClone(new Set([1, 2, 3])); // => new Set([1, 2, 3]) ``` *Or use it without global namespace pollution*: ```js import Promise from 'core-js-pure/actual/promise'; import Set from 'core-js-pure/actual/set'; import Iterator from 'core-js-pure/actual/iterator'; import from from 'core-js-pure/actual/array/from'; import flatMap from 'core-js-pure/actual/array/flat-map'; import structuredClone from 'core-js-pure/actual/structured-clone'; Promise.resolve(42).then(it => console.log(it)); // => 42 from(new Set([1, 2, 3]).union(new Set([3, 4, 5]))); // => [1, 2, 3, 4, 5] flatMap([1, 2], it => [it, it]); // => [1, 1, 2, 2] Iterator.from(function * (i) { while (true) yield i++; }(1)) .drop(1).take(5) .filter(it => it % 2) .map(it => it ** 2) .toArray(); // => [9, 25] structuredClone(new Set([1, 2, 3])); // => new Set([1, 2, 3]) ``` **It's a global version (first 2 examples), for more info see [`core-js` documentation](https://github.com/zloirock/core-js/blob/master/README.md).**

	Stars	Issues	Version	Updated	Created
core-js	23,939	34	3.37.1	5 days ago	11 years ago
es6-shim	3,116	33	0.35.8	a year ago	12 years ago
polyfill-library			4.8.0	a year ago	6 years ago
polyfill-service	7,516	24	3.25.3	5 years ago	9 years ago

core-js vs es6-shim vs polyfill-library vs polyfill-service

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