core-js

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I highly recommend reading this: So, what's next?
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> Modular standard library for JavaScript. Includes polyfills for ECMAScript up to 2025: 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.

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Example of usage:
``js
import 'core-js/actual';

Promise.try(() => 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]

Iterator.concat([1, 2], function * (i) { while (true) yield i++; }(3))
.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.try(() => 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]

Iterator.concat([1, 2], function * (i) { while (true) yield i++; }(3))
.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.try(() => 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.concat([1, 2], function * (i) { while (true) yield i++; }(3))
.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.