59 lines
5.4 KiB
Markdown
59 lines
5.4 KiB
Markdown
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# core-js
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[](#sponsors) [](#backers) [](https://gitter.im/zloirock/core-js?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge) [](https://www.npmjs.com/package/core-js) [](http://npm-stat.com/charts.html?package=core-js&author=&from=2014-11-18) [](https://travis-ci.org/zloirock/core-js) [](https://david-dm.org/zloirock/core-js?type=dev)
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> Modular standard library for JavaScript. Includes polyfills for [ECMAScript up to 2019](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.
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## As advertising: the author is looking for a good job -)
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## [core-js@3, babel and a look into the future](https://github.com/zloirock/core-js/tree/master/docs/2019-03-19-core-js-3-babel-and-a-look-into-the-future.md)
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## Raising funds
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`core-js` isn't backed by a company, so the future of this project depends on you. Become a sponsor or a backer [**on Open Collective**](https://opencollective.com/core-js) or [**on Patreon**](https://www.patreon.com/zloirock) if you are interested in `core-js`.
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---
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<a href="https://opencollective.com/core-js/sponsor/0/website" target="_blank"><img src="https://opencollective.com/core-js/sponsor/0/avatar.svg"></a><a href="https://opencollective.com/core-js/sponsor/1/website" target="_blank"><img src="https://opencollective.com/core-js/sponsor/1/avatar.svg"></a><a href="https://opencollective.com/core-js/sponsor/2/website" target="_blank"><img src="https://opencollective.com/core-js/sponsor/2/avatar.svg"></a><a href="https://opencollective.com/core-js/sponsor/3/website" target="_blank"><img src="https://opencollective.com/core-js/sponsor/3/avatar.svg"></a><a href="https://opencollective.com/core-js/sponsor/4/website" target="_blank"><img src="https://opencollective.com/core-js/sponsor/4/avatar.svg"></a><a href="https://opencollective.com/core-js/sponsor/5/website" target="_blank"><img src="https://opencollective.com/core-js/sponsor/5/avatar.svg"></a><a href="https://opencollective.com/core-js/sponsor/6/website" target="_blank"><img src="https://opencollective.com/core-js/sponsor/6/avatar.svg"></a><a href="https://opencollective.com/core-js/sponsor/7/website" target="_blank"><img src="https://opencollective.com/core-js/sponsor/7/avatar.svg"></a><a href="https://opencollective.com/core-js/sponsor/8/website" target="_blank"><img src="https://opencollective.com/core-js/sponsor/8/avatar.svg"></a><a href="https://opencollective.com/core-js/sponsor/9/website" target="_blank"><img src="https://opencollective.com/core-js/sponsor/9/avatar.svg"></a><a href="https://opencollective.com/core-js/sponsor/10/website" target="_blank"><img src="https://opencollective.com/core-js/sponsor/10/avatar.svg"></a><a href="https://opencollective.com/core-js/sponsor/11/website" target="_blank"><img src="https://opencollective.com/core-js/sponsor/11/avatar.svg"></a>
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---
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<a href="https://opencollective.com/core-js#backers" target="_blank"><img src="https://opencollective.com/core-js/backers.svg?width=890"></a>
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---
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[*Example*](http://goo.gl/a2xexl):
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```js
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import 'core-js'; // <- at the top of your entry point
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Array.from(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]
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[1, [2, 3], [4, [5]]].flat(2); // => [1, 2, 3, 4, 5]
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Promise.resolve(32).then(x => console.log(x)); // => 32
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```
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*You can load only required features*:
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```js
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import 'core-js/features/array/from'; // <- at the top of your entry point
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import 'core-js/features/array/flat'; // <- at the top of your entry point
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import 'core-js/features/set'; // <- at the top of your entry point
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import 'core-js/features/promise'; // <- at the top of your entry point
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Array.from(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]
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[1, [2, 3], [4, [5]]].flat(2); // => [1, 2, 3, 4, 5]
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Promise.resolve(32).then(x => console.log(x)); // => 32
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```
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*Or use it without global namespace pollution*:
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```js
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import from from 'core-js-pure/features/array/from';
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import flat from 'core-js-pure/features/array/flat';
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import Set from 'core-js-pure/features/set';
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import Promise from 'core-js-pure/features/promise';
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from(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]
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flat([1, [2, 3], [4, [5]]], 2); // => [1, 2, 3, 4, 5]
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Promise.resolve(32).then(x => console.log(x)); // => 32
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```
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**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).**
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