Returns true if a value has the characteristics of a valid JavaScript data descriptor.

Encodings that map abstract data to visual representation.

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

Robust call-bound JavaScript intrinsics, using `call-bind` and `get-intrinsic`.

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

ES6 spec-compliant Object.assign shim. From https://github.com/es-shims/es6-shim

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

A querystring parser that supports nesting and arrays, with a depth limit

Determine if a function is a native generator function.

resolve like require.resolve() on behalf of files asynchronously and synchronously

ES6 spec-compliant RegExp.prototype.flags shim.

A light-weight module that brings Fetch API to node.js

A library for obtaining browser versions with their maximum supported Baseline feature set and Widely Available status.

Implementation of Function.prototype.bind

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

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

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

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

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

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