JSPM

A robust & optimized `String.prototype.repeat` polyfill, based on the ECMAScript 6 specification.

ES2017 spec-compliant Object.values shim.

An ES7/ES2016 spec-compliant `Array.prototype.includes` shim/polyfill/replacement that works as far down as ES3.

Symbol.observable ponyfill

An ES2015 mostly-spec-compliant `Reflect.getPrototypeOf` sham/polyfill/replacement that works in as many engines as possible

ES proposal-spec-compliant Object.fromEntries shim.

An ES2019 spec-compliant `Array.prototype.flatMap` shim/polyfill/replacement that works as far down as ES3.

TypedArray polyfill for old browsers

Web Streams, based on the WHATWG spec reference implementation

ES2017 spec-compliant Object.entries shim.

A robust & optimized `String.prototype.includes` polyfill, based on the ECMAScript 6 specification.

An ESnext spec-compliant `Array.prototype.toSorted` shim/polyfill/replacement that works as far down as ES3.

An ESnext spec-compliant `Array.prototype.findLast` shim/polyfill/replacement that works as far down as ES3.

A robust polyfill for the `CSS.escape` utility method as defined in CSSOM.

An ESnext spec-compliant `Object.groupBy` shim/polyfill/replacement that works as far down as ES3.

An ESnext spec-compliant iterator helpers shim/polyfill/replacement that works as far down as ES3.

WASI polyfill for browser and some wasm util

requestAnimationFrame polyfill for node and the browser

ES2015 Promise ponyfill

Assign the enumerable es6 Symbol properties from one or more objects to the first object passed on the arguments. Can be used as a supplement to other extend, assign or merge methods as a polyfill for the Symbols part of the es6 Object.assign method.

Standard library

A lightweight library that provides tools for organizing asynchronous code

ECMAScript extensions and shims

An ES5 spec-compliant `Array.prototype.reduce` shim/polyfill/replacement that works as far down as ES3.

ES2017 spec-compliant shim for `Object.getOwnPropertyDescriptors` that works in ES5.

Use the :focus-within pseudo-selector in CSS

Style form elements when they are empty

HTML5 `FormData` for Browsers and Node.

A JavaScript (JS) Map or Similar object polyfill if Map is not available.

ECMAScript 6 Symbol polyfill

AbortController for Node based on EventEmitter

Node.js os.homedir polyfill for older versions of node.js.

Polyfill/shim for util.promisify in node versions < v8

ES2015-compliant shim for Number.isNaN - the global isNaN returns false positives.

A polyfill for the Resize Observer API

JavaScript utilities with respect to emerging standard

ES spec-compliant shim for Object.hasOwn

Node.js path.dirname() ponyfill

Object.fromEntries() ponyfill (in 6 lines)

Returns true if a file path is absolute. Does not rely on the path module and can be used as a polyfill for node.js native `path.isAbolute`.

Style elements relative to other elements in CSS

ES2015 `Array#findIndex()` ponyfill

A pseudo-class for matching elements in a selector list

A tiny, zero-dependency yet spec-compliant asynchronous iterator polyfill/ponyfill for ReadableStreams.

Polyfill crypto.randomUUID

Use the :dir pseudo-class in CSS

Bare minimum fetch polyfill in 500 bytes

Polyfills the ResizeObserver API and supports box size options from the latest spec

This is a polyfill for Buffer#indexOf introduced in NodeJS 4.0.

is that thing a function? Use this module to find out

ES2017 spec-compliant String.prototype.padEnd shim.

backwards compatible version of builtin events.listenercount

Performance timer based on performance.mark() and measure()

An ES5 spec-compliant `Array.prototype.map` shim/polyfill/replacement that works as far down as ES3.

Polyfills for React Native.

Ponyfill for upcoming Element.scrollIntoView() APIs like scrollMode: if-needed, behavior: smooth and block: center

Minimal zero-dependency utilities for using JavaScript Iterables in all environments.

Simple setImmediate shim

Array.prototype.find ES6 polyfill.

ECMAScript6 Map polyfill

Error.captureStackTrace ponyfill

ES spec-compliant shim for TypedArray.prototype.slice

An ESnext spec-compliant `Array.prototype.toReversed` shim/polyfill/replacement that works as far down as ES3.

A ponyfill for the ES 2015 (ES6) `Array.from()`.

Common layer to be used by crypto libraries based on WebCrypto API for input validation.

Polyfill exporting trevnorris's 0.11+ asyncListener API.

ECMAScript 2015 (ES6) Object.assign polyfill and ponyfill

Fork of eventsource package - W3C compliant EventSource client for Node.js and browser (polyfill)

A BroadcastChannel that works in New Browsers, Old Browsers, WebWorkers, NodeJs, Deno and iframes

Polyfill for the Encoding Living Standard's API.

Support any Observable library and polyfill

A robust & optimized `String.fromCodePoint` polyfill, based on the ECMAScript 6 specification.

ES Proposal spec-compliant shim for AggregateError

ES Proposal spec-compliant shim for Promise.allSettled

Polyfill Node.js core modules in Webpack.

Polyfill for the proposed React context API

An ES5 spec-compliant `Array.prototype.filter` shim/polyfill/replacement that works as far down as ES3.

Path2D API for node. Can be used for server-side rendering with canvas

Polyfill for: https://tc39.es/proposal-intl-displaynames

A cross platform Promise.allSettled polyfill

ES Proposal spec-compliant shim for Promise.prototype.finally

ECMAScript 5 compatibility shims for legacy JavaScript engines

ES2019 spec-compliant String.prototype.trimLeft shim.

ES2017 spec-compliant String.prototype.padStart shim.

Spec-compliant shim for Symbol.prototype.description proposal.

A small implementation of `crypto.getRandomValues` for React Native. This is useful to polyfill for libraries like [uuid](https://www.npmjs.com/package/uuid) that depend on it.

ES2019 spec-compliant String.prototype.trimLeft shim.

A lightweight and trustworthy URL polyfill for React Native

ES2015 spec-compliant shim for Reflect.ownKeys

Polyfill for the proposed React context API

ES6 Array.find ponyfill. Return the first array element which satisfies a testing function.

Polyfills Path2D api for canvas rendering

Fake IndexedDB: a pure JS in-memory implementation of the IndexedDB API

A ponyfill (doesn't overwrite the native methods) to use Edge Runtime APIs in any environment.

A robust & optimized `String.prototype.codePointAt` polyfill, based on the ECMAScript 6 specification.

The fastest smallest Javascript polyfill for the encode of TextEncoder and decode of TextDecoder for UTF-8 only. Made by AnonyCo with ❤️ from 🐕s.

finds an item in an array matching a predicate function, and returns its index

A polyfill for http://www.w3.org/TR/eventsource/

Polyfill the ECMA-402 Intl API (except collation)

An ESnext spec-compliant shim/polyfill/replacement for all Well-Known Symbols that works in any environment with Symbols.

Smooth Scroll behavior polyfill

Ensure a path doesn't contain null bytes

a simple polyfill for javascript URLSearchParams

ES2015 (ES6) Number.isInteger polyfill

Polyfill/shim for `document.contains`

Text Decoder

Comprehensive TypeScript/JavaScript utility library with cross-environment support (Node.js, browser, web worker) providing helper functions, polyfills (ES5-ES2023), type checking utilities, and optimized implementations for better minification and code r

EventSource polyfill for browser and node.js

Return the prototype of a provided object.

Cross-browser JavaScript shim that fully implements element.classList (referenced on MDN)

ECMAScript6 WeakMap polyfill

A polyfill for creating CustomEvents on IE9+ if the native implementation is missing.

Ponyfill for ES2020 Intl.NumberFormat

Intl.MessageFormat / Unicode MessageFormat 2 parser, runtime and polyfill

Polyfill for Intl.PluralRules

Test whether a path exists on the filesystem.

Polyfill for perf_hooks.monitorEventLoopDelay(...)

Polyfills nodejs builtin modules and globals for the browser.

Blob.js implements the W3C Blob interface in browsers that do not natively support it.

A browser polyfill for W3C EventSource (http://www.w3.org/TR/eventsource/)

Mouse state change listener

Cross browser mouse event property access

JavaScript implementation of the Web Animations API

Intl.DateTimeFormat polyfill

A Javascript polyfill for browsers that don't support the object-fit CSS property

Polyfill for Scoped CSS

The URLSearchParams polyfill.

HTML Custom Elements Polyfill

An implementation and polyfill of the Resize Observer draft.

Web Components Polyfills

An ES5 spec-compliant `Array.prototype.every` shim/polyfill/replacement that works as far down as ES3.

Return the closest element matching a selector up the DOM tree

Promise.witResolvers() polyfill

A polyfill for the asynchronous clipboard API

WebGL2 API Polyfills for WebGL1 WebGLRenderingContext

A polyfill for the encryptionScheme field in EME

ES 2021 spec-compliant shim for Promise.any

Client-side support for CSS custom properties (aka "CSS variables") in legacy and modern browsers

A robust ES3-compatible polyfill for the `RegExp.escape` proposal - see https://github.com/tc39/proposal-regex-escaping

Constructible style sheets/adopted style sheets polyfill

A BroadcastChannel that works in New Browsers, Old Browsers, WebWorkers

Ponyfill for smooth scrolling elements into view (if needed!)

Wrapper for the Page Visibility API

A polyfill for the proposed inert API

A Barcode Detection API polyfill that uses ZXing webassembly under the hood

Polyfill for the Proxy object

Polyfill object-fit and object-position on images on IE9, IE10, IE11, Edge, Safari, ...

Deno namespace shim for Node.js

Polyfill for navigator.sendBeacon()

An ES spec-compliant `Array.prototype.forEach` shim/polyfill/replacement that works as far down as ES3.

Polyfill for RFC 566: @cached

An ES-spec-compliant (proposed) Array.prototype.at shim/polyfill/replacement that works as far down as ES3

Polyfill for RFC 580: Destroyables

A fork of create-react-context in MIT license

Polyfill for the basic functionality of `Function.name` accessor property in its pre-ES6 form

An ES5 mostly-spec-compliant `Object.getPrototypeOf` sham/polyfill/replacement that works in as many engines as possible

polyfill for `KeyboardEvent.prototype.key`

A polyfill for Ember CLI's TypeScript blueprint capabilities.

Javascript Error Polyfill

A robust & optimized `String.prototype.startsWith` polyfill, based on the ECMAScript 6 specification.

A polyfill for the Record and Tuple Stage 2 ECMAScript proposal.

A cross browser solution to scrolling during drag and drop.

This package includes the [core-js](https://github.com/zloirock/core-js) polyfill for `String#replaceAll`, along with TypeScript typings.

Polyfill requestAnimationFrame and cancelAnimationFrame

Popover Attribute Polyfill

Smooth Scroll behavior polyfill

MediaRecorder polyfill to record audio in Edge and Safari

A Javascript utility library for working with native objects.

A polyfill for the element internals specification

PostCSS plugin for Flexibility polyfill

JavaScript polyfill for the WHATWG spec of focusOptions, that enables a set of options to be passed to the focus method.

CSSOM-valid and jsdom/Jest-compatible matchMedia polyfill for server-side unit tests

A polyfill for Ember.assign in <= 2.4

CanvasRenderingContext2D.roundRect() and Path2D.roundRect() polyfill

Standard library

Transit is a data format and a set of libraries for conveying values between applications written in different languages. This library provides support for marshalling Transit data to/from Javascript.

A JavaScript polyfill for Flexbox

MDN polyfills

Polyfill for ES6 Promise

Super small `Element.matches` fix for older browsers (IE 9+, Edge 12+, Safari, Android browsers)

A polyfill for crypto.randomFill and crypto.randomFillSync from Node.js core

ECMAScript 7 compatibility shims for legacy JavaScript engines

A polyfill for the 'scroll-behavior' CSS-property

A minimal polyfill for Element.closest

Returns the first index at which a given element can be found.

Quick wrapper that finds TextDecoder or polyfills a bad implementation

Polyfill for CSS `position: sticky`

<form>.requestSubmit() polyfill

Replaces `arr.includes(val)' with `arr.indexOf(val) >= 0`.

Polyfill for making HTML5 drag and drop possible in all browsers.

W3C's Fullscreen API Polyfill

Node's util.inspect, extracted for use on the Web

Return the first index at which a given element can be found.

Round a double-precision floating-point number toward zero.

User Timing polyfill

Simple ES6 Object.assign() polyfill for older environments.

Browser polyfill for making React Native compatible with web libs like pixi.js, three.js, phaser.js

A polyfill that fetches external SVGs referenced in use elements when the browser itself fails to do so.

Provide helpers that polyfill all methods defined in [iterator helpers proposal](https://github.com/tc39/proposal-iterator-helpers), both for `Iterator` and `AsyncIterator`, and even more.

A robust & optimized `String.prototype.endsWith` polyfill, based on the ECMAScript 6 specification.

All inclusive customElements polyfill for every browser

WebAssembly interpreter

A polyfill for the Resize Observer API

`Object.entries()` ponyfill

An ES-spec-compliant shim/polyfill/replacement for the `.cause` property on all Error types that works as far down as ES3

Validate your forms, frontend, without writing a single line of javascript!

Polyfill/shim for stream.finished in node versions < v10

Scoped CustomElementRegistry Polyfill

An EventTarget polyfill

HTML <details> element polyfill

Runtime polyfills for TypeScript libs, powered by core-js!

A polyfill for the native import() in the browser

Polyfill for the proposed CSS anchor positioning spec

Compatibility layer for efficient streaming of binary data using [WHATWG Streams](https://streams.spec.whatwg.org/)

React component for anchor links using the smoothscroll polyfill.

Polyfill/shim for stream.pipeline in node versions < v10

Object.fromEntries() polyfill

An ES-spec-compliant Set shim/polyfill/replacement that works as far down as ES3

An ESnext spec-compliant `DisposableStack`, `AsyncDisposableStack`, `Symbol.dispose`, and `Symbol.asyncDispose` shim/polyfill/replacement that works as far down as ES3.

Object.setPrototypeOf Polyfill

An ESnext spec-compliant `Set.prototype.difference` shim/polyfill/replacement that works as far down as ES3

Patches global.Promise to use bluebird and returns a bluebird instance

fs.promises polyfill

Tiny Web Share API Wrapper with fallback for unsupported browsers

ES Proposal spec-compliant shim for SuppressedError

An ES-spec-compliant Map shim/polyfill/replacement that works as far down as ES3

A browser polyfill for W3C EventSource (http://www.w3.org/TR/eventsource/)

A cross browser solution to scrolling during drag and drop.

Cross-browser implementation of W3C saveAs API

A polyfill of IntersectionObserver API

Standardizer for node's console.assert

polyfill for es8 Object.values

Polyfills and patches missing or partially supported web and core APIs

ECMAScript Map like object.

Polyfills the a[download] attribute

The minimal set of polyfills that the Aurelia platform needs to run on ES5 browsers.

Compute the arcsine of a double-precision floating-point number.

Polyfill for scrollend event

An ES5 spec-compliant `Array.prototype.some` shim/polyfill/replacement that works as far down as ES3.

Determines whether a string ends with the characters of another string.

get-own-property-symbols ========================

Simple, small and fast jQuery polyfill for the HTML5 <input type="range"> slider element

Polyfill Web Speech API with Cognitive Services Speech-to-Text service

TypeScript shim for DOMMatrix

Polyfill for BroadcastChannel for Safari, old Chrome and Opera

A polyfill for the proposed blocking elements stack API

A canvas.toBlob() implementation

PostCSS plugin that updates the standard object-fit tag to work with the object-fit-images polyfill for browsers that do not natively support object-fit.

Run ES Module syntax in any browser – even IE!

Polyfill to provide array.find on IE.