core-js

Modular standard library for JavaScript. Includes polyfills for ECMAScript up to 2021: 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.

As advertising: the author is looking for a good job -)

core-js@3, babel and a look into the future

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 on Open Collective or on Patreon if you are interested in core-js.

Example:

import 'https://deno.land/x/corejs@v3.16.1/index.js'; // <- at the top of your entry point

Object.hasOwn({ foo: 42 }, 'foo'); // => true

[1, 2, 3, 4, 5, 6, 7].at(-3);      // => 5

Promise.any([
  Promise.resolve(1),
  Promise.reject(2),
  Promise.resolve(3),
]).then(console.log);              // => 1

[1, 2, 3, 4, 5, 6, 7].values()
  .drop(1)
  .take(5)
  .filter(it => it % 2)
  .map(it => it ** 2)
  .toArray();                     // => [9, 25]

It’s a bundled global version for Deno 1.0+, for more info see core-js documentation.