Helper function for exhaustive checks of discriminated unions in TypeScript

Like a Set, but provides the index of the `key` in the backing array

The assert module from Node.js, for the browser.

minimalistic-assert ===

Synchronous validation of a path existing either as a file or as a directory.

Parses, serializes, and manipulates MIME types, according to the WHATWG MIME Sniffing Standard

correct invalid SPDX expressions

A robust, ES3 compatible, "has own property" predicate.

assert with status codes

Extra assertions on top of node's assert module

Is this value a JS SharedArrayBuffer?

Which kind of boxed JS primitive is this?

Is this value a JS ArrayBuffer?

What is the type of this builtin JS value?

Is this value a JS Typed Array? This module works cross-realm/iframe, does not depend on `instanceof` or mutable properties, and despite ES6 Symbol.toStringTag.

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

`Object.getOwnPropertyDescriptor`, but accounts for IE's broken implementation.

Robustly get the length of a Typed Array

Is this specifier a node.js core module?

`Object.defineProperty`, but not IE 8's broken one.