Assertion

Assertion Library for Browser and Node.JS

Error constructor for test and validation frameworks that implements standardized AssertionError specification.

Format errors to display a diff between the actual and expected

Allow parsing of the module assertion attributes in the import statement

Support for import assertions in acorn

Pass two numbers, get a regex-compatible source string for matching ranges. Validated against more than 2.78 million test assertions.

Validate XML, Parse XML, Build XML without C/C++ based libraries

Extra assertions on top of node's assert module

Type check values

minimalistic-assert ===

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

A tiny invariant function

String validation and sanitization

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

simple, flexible, fun test framework

Lazy assertions without performance penalty

JavaScript test spies, stubs and mocks.

flow typed nullthrows

Featherweight assert module

Yet another JavaScript assertion/invariant library.

TypeScript implementation of invariant(condition, message)

A little library for asserting types and values, with zero dependencies.

Do things in development and nothing otherwise

typesafe assertion library for TypeScript 3.7+

uvu is an extremely fast and lightweight test runner for Node.js and the browser

[](https://github.com/mmkal/expect-type/actions/workflows/ci.yml)  [![X (formerly Twitter) Follow](https://img.shields.io/twitte

assert with status codes

assertion renderer for power-assert context

Adaptation of react-addons-shallow-compare, for independent usage

JavaScript Testing utilities for React

A simple and composable way to validate data in JavaScript (and TypeScript).

TypeScript definitions for http-assert

test framework agnostic BDD-style assertions

Next-gen browser and mobile automation test framework for Node.js

Additional Jest matchers

Helper function for exhaustive checks of discriminated unions in TypeScript

Type assertions aka less-broken `typeof`

Extends Chai with assertions about promises.

Hook and modify stdout and stderr

JavaScript Testing utilities for React

JavaScript Testing utilities for React

Disallow type assertions in TypeScript code

WebdriverIO Assertion Library

Function argument validation for humans

Extends Chai with assertions for the Sinon.JS mocking framework.

Useful utilities for working with Uint8Array (and Buffer)

Better assertions for node, reporting the expr, filename, lineno etc

A tiny javascript type testing tool

Precondition checking utilities.

tap-producing test harness for node and browsers