ES spec-like internal slots
An ES2015 mostly-spec-compliant `Reflect.getPrototypeOf` sham/polyfill/replacement that works in as many engines as possible
Does this JS environment support the `name` property on functions?
An ES2019 spec-compliant `Array.prototype.flat` shim/polyfill/replacement that works as far down as ES3.
Gets the description of a Symbol. Handles `Symbol()` vs `Symbol('')` properly when possible.
Fast, disk space efficient package manager
An ES7/ES2016 spec-compliant `Array.prototype.includes` shim/polyfill/replacement that works as far down as ES3.
Simple and complete DOM testing utilities that encourage good testing practices.
ES Math-related intrinsics and helpers, robustly cached.
A library for obtaining browser versions with their maximum supported Baseline feature set and Widely Available status.
ECMAScript “ToPrimitive” algorithm. Provides ES5 and ES2015 versions.
Is this value a JS regex? Works cross-realm/iframe, and despite ES6 @@toStringTag
TypeScript-first schema declaration and validation library with static type inference
An ESnext spec-compliant `Array.prototype.findLast` shim/polyfill/replacement that works as far down as ES3.
Is this value a JS Boolean? This module works cross-realm/iframe, and despite ES6 @@toStringTag.
Helper functions for V8 coverage files.
ES2017 spec-compliant Object.values shim.
Determine if the JS environment has BigInt support.
ECMAScript spec-compliant polyfill/shim for `globalThis`
Unbox a boxed JS primitive value.
An ESnext spec-compliant `Array.prototype.findLastIndex` shim/polyfill/replacement that works as far down as ES3.
Helper package to shim a method into `Array.prototype[Symbol.unscopables]`
Simple and complete React DOM testing utilities that encourage good testing practices.
Encode FormData content into the multipart/form-data format