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

Type check values

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

A tiny invariant function

minimalistic-assert ===

Extra assertions on top of node's assert module

String validation and sanitization

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

simple, flexible, fun test framework

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Do things in development and nothing otherwise

JavaScript test spies, stubs and mocks.

flow typed nullthrows

Lazy assertions without performance penalty

assertion renderer for power-assert context

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

Helpers for asserting that a JavaScript environment supports certain features necessary for the operation of the Solana JavaScript SDK

Featherweight assert module

TypeScript implementation of invariant(condition, message)

Useful utilities for working with Uint8Array (and Buffer)

assert with status codes

typesafe assertion library for TypeScript 3.7+

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

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

test framework agnostic BDD-style assertions

Yet another JavaScript assertion/invariant library.

TypeScript definitions for http-assert

Hook and modify stdout and stderr

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

Helper function for exhaustive checks of discriminated unions in TypeScript

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

Extends Chai with assertions about promises.

JavaScript Testing utilities for React

Type assertions aka less-broken `typeof`

Additional Jest matchers

Function argument validation for humans

WebdriverIO Assertion Library

JavaScript Testing utilities for React

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

A tiny javascript type testing tool

JavaScript Testing utilities for React

Rich matchers inspired by Hamcrest. Useful for generating helpful assertion failure messages in tests.

tap-producing test harness for node and browsers

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