core-js-pure
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Package description
The core-js-pure package is a version of core-js that doesn't pollute the global namespace. It provides polyfills for ECMAScript features, including promises, symbols, collections, iterators, typed arrays, and many other features that are part of the ECMAScript specification but may not be available in all JavaScript environments.
Polyfilling Promises
This code sample demonstrates how to polyfill Promises using core-js-pure. It allows you to use Promises in environments where they are not natively supported.
import 'core-js-pure/stable/promise';
const promise = Promise.resolve(42);
promise.then(value => console.log(value));Polyfilling Array methods
This code sample shows how to polyfill Array.prototype.find method. It enables the use of this method in environments where it is not part of the Array prototype.
import 'core-js-pure/stable/array/find';
const array = [1, 2, 3];
const found = array.find(item => item > 1);
console.log(found); // 2Polyfilling Object static methods
This code sample illustrates how to polyfill Object.assign method. It allows the merging of multiple source objects into a target object in environments that do not support this method natively.
import 'core-js-pure/stable/object/assign';
const target = { a: 1 };
const source = { b: 2 };
const returnedTarget = Object.assign(target, source);
console.log(returnedTarget); // { a: 1, b: 2 }Polyfilling String methods
This code sample demonstrates how to polyfill String.prototype.includes method. It provides a way to check if one string may be found within another string, returning true or false as appropriate.
import 'core-js-pure/stable/string/includes';
const string = 'hello world';
const includesHello = string.includes('hello');
console.log(includesHello); // trueBabel-polyfill is a package that includes core-js and a custom regenerator runtime to emulate a full ES2015+ environment. It's similar to core-js-pure but is more tightly coupled with Babel's transpilation process.
The es6-shim package provides polyfills for many new JavaScript features introduced in ES5 and ES6. It is similar to core-js-pure but does not offer as modular an approach, and it may include shims for features that are not strictly polyfills.
The polyfill-service (also known as polyfill.io) is a service that provides polyfills based on the user's browser user-agent. Unlike core-js-pure, it is a service rather than a package you include in your code, and it dynamically serves only the polyfills needed by the browser.
Changelog
Iterator
Iterator.fromIterator.prototype.dropIterator.prototype.everyIterator.prototype.filterIterator.prototype.findIterator.prototype.flatMapIterator.prototype.forEachIterator.prototype.mapIterator.prototype.reduceIterator.prototype.someIterator.prototype.takeIterator.prototype.toArrayIterator.prototype.toAsyncIterator.prototype[@@toStringTag]AsyncIterator
AsyncIterator.fromAsyncIterator.prototype.dropAsyncIterator.prototype.everyAsyncIterator.prototype.filterAsyncIterator.prototype.findAsyncIterator.prototype.flatMapAsyncIterator.prototype.forEachAsyncIterator.prototype.mapAsyncIterator.prototype.reduceAsyncIterator.prototype.someAsyncIterator.prototype.takeAsyncIterator.prototype.toArrayAsyncIterator.prototype[@@toStringTag]/actual/ entries, unconditional forced replacement disabled for features that survived to Stage 3.from accept strings, .flatMap throws on strings returned from the callback, proposal-iterator-helpers/244, proposal-iterator-helpers/250.from and .flatMap throws on non-object iterators, proposal-iterator-helpers/253Set methods proposal:
Set.prototype.intersectionSet.prototype.unionSet.prototype.differenceSet.prototype.symmetricDifferenceSet.prototype.isSubsetOfSet.prototype.isSupersetOfSet.prototype.isDisjointFromSet-like objects as an argument, not all iterablesSets as this, no @@species support, and other minor changes/actual/ entries, unconditional forced replacement changed to feature detection/actual/ namespace)/full/ namespace), those methods are available with fallbacks to old semantics (in addition to Set-like, they accept iterable objects). This behavior will be removed from the next major releaseString.prototype.isWellFormedString.prototype.toWellFormed/actual/ entries, disabled unconditional forced replacementusing statement" and split into 2 (sync and async) proposalsSymbol.disposeSymbol.asyncDisposeSuppressedErrorDisposableStack
DisposableStack.prototype.disposeDisposableStack.prototype.useDisposableStack.prototype.adoptDisposableStack.prototype.deferDisposableStack.prototype.moveDisposableStack.prototype[@@dispose]AsyncDisposableStack
AsyncDisposableStack.prototype.disposeAsyncAsyncDisposableStack.prototype.useAsyncDisposableStack.prototype.adoptAsyncDisposableStack.prototype.deferAsyncDisposableStack.prototype.moveAsyncDisposableStack.prototype[@@asyncDispose]Iterator.prototype[@@dispose]AsyncIterator.prototype[@@asyncDispose]/actual/ namespace entries for Stage 3 proposalString.dedent stage 2 proposal
String.dedentreact-native target for React Native with bundled Hermes.oculus target was renamed to quest.opera_mobile target name is confusing since it contains data for the Chromium-based Android version, but iOS Opera is Safari-based. So opera_mobile target was renamed to opera-android.android target name is also confusing for someone - that means Android WebView, some think thinks that it's Chrome for Android, but they have some differences. For avoiding confusion, added chrome-android target.firefox-android target.oculus and opera_mobile fields are available in the compat data till the next major release.Array.fromAsync marked as supported from Bun 0.3.0String.prototype.{ isWellFormed, toWellFormed } marked as supported from Bun 0.4.0Array by copy proposal marked as supported from Deno 1.27, deno/16429{ Map, WeakMap }.prototype.emplace became stricter by the spec draft@@species pattern) of some .prototype methods from the new collections methods proposal and the Array deduplication proposal that most likely will not be implemented since it contradicts the current TC39 policyNumber constructor, #1154, #1155, thanks @trososset(Timeout|Interval|Immediate) extra arguments fix for Bun 0.3.0- (similarly to IE9-), bun/1633structuredClone, #1156Readme
Modular standard library for JavaScript. Includes polyfills for ECMAScript up to 2023: 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 if you are interested in core-js: Open Collective, Patreon, Bitcoin ( bc1qlea7544qtsmj2rayg0lthvza9fau63ux0fstcz ).
import 'core-js/actual'; // <- at the top of your entry point
Array.from(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]
[1, 2, 3, 4, 5].group(it => it % 2); // => { 1: [1, 3, 5], 0: [2, 4] }
Promise.resolve(42).then(x => console.log(x)); // => 42
structuredClone(new Set([1, 2, 3])); // => new Set([1, 2, 3])
queueMicrotask(() => console.log('called as microtask'));
You can load only required features:
import 'core-js/actual/array/from'; // <- at the top of your entry point
import 'core-js/actual/array/group'; // <- at the top of your entry point
import 'core-js/actual/set'; // <- at the top of your entry point
import 'core-js/actual/promise'; // <- at the top of your entry point
import 'core-js/actual/structured-clone'; // <- at the top of your entry point
import 'core-js/actual/queue-microtask'; // <- at the top of your entry point
Array.from(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]
[1, 2, 3, 4, 5].group(it => it % 2); // => { 1: [1, 3, 5], 0: [2, 4] }
Promise.resolve(42).then(x => console.log(x)); // => 42
structuredClone(new Set([1, 2, 3])); // => new Set([1, 2, 3])
queueMicrotask(() => console.log('called as microtask'));
Or use it without global namespace pollution:
import from from 'core-js-pure/actual/array/from';
import group from 'core-js-pure/actual/array/group';
import Set from 'core-js-pure/actual/set';
import Promise from 'core-js-pure/actual/promise';
import structuredClone from 'core-js-pure/actual/structured-clone';
import queueMicrotask from 'core-js-pure/actual/queue-microtask';
from(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]
group([1, 2, 3, 4, 5], it => it % 2); // => { 1: [1, 3, 5], 0: [2, 4] }
Promise.resolve(42).then(x => console.log(x)); // => 42
structuredClone(new Set([1, 2, 3])); // => new Set([1, 2, 3])
queueMicrotask(() => console.log('called as microtask'));
It's a version without global namespace pollution (the third example), for more info see core-js documentation.
FAQs
Standard library
The npm package core-js-pure receives a total of 10,139,152 weekly downloads. As such, core-js-pure popularity was classified as popular.
We found that core-js-pure demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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