Define a data property on an object. Will fall back to assignment in an engine without descriptors.

Terminal task list reborn! Create beautiful CLI interfaces via easy and logical to implement task lists that feel alive and interactive.

Implementation of Function.prototype.bind

The `postinstall` script helper for handling native bindings in legacy `npm` versions

Define multiple non-enumerable properties at once. Uses `Object.defineProperty` when available; falls back to standard assignment in older engines.

BDD/TDD assertion library for node.js and the browser. Test framework agnostic.

javascript standard data structure library which benchmark against C++ STL

Simple and complete DOM testing utilities that encourage good testing practices.

An ESnext spec-compliant `Array.prototype.findLastIndex` 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.

Returns an array of Typed Array names that are available in the current environment

Which kind of Typed Array is this JavaScript value? Works cross-realm, without `instanceof`, and despite Symbol.toStringTag.

Is this value a JS FinalizationRegistry? This module works cross-realm/iframe, and despite ES6 @@toStringTag.

Determine if a function is a native generator function.

Does this JS environment support the `name` property on functions?

Standard library

Fire events the same way the user does

Is this JS value callable? Works with Functions and GeneratorFunctions, despite ES6 @@toStringTag.

ES Math-related intrinsics and helpers, robustly cached.

Custom jest matchers to test the state of the DOM