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 features and proposals like
URL
. You can load only required features or use it without global namespace pollution.
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 or on Patreon if you are interested in core-js
.
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
It's a global version (first 2 examples), for more info see core-js
documentation.