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

minimalistic-assert ===

Extra assertions on top of node's assert module

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

JavaScript test spies, stubs and mocks.

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Lazy assertions without performance penalty

flow typed nullthrows

Featherweight assert module

Do things in development and nothing otherwise

TypeScript implementation of invariant(condition, message)

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

Yet another JavaScript assertion/invariant library.

typesafe assertion library for TypeScript 3.7+

assert with status codes

assertion renderer for power-assert context

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

Useful utilities for working with Uint8Array (and Buffer)

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

test framework agnostic BDD-style assertions

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

TypeScript definitions for http-assert

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

Hook and modify stdout and stderr

Helper function for exhaustive checks of discriminated unions in TypeScript

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

Type assertions aka less-broken `typeof`

Additional Jest matchers

Extends Chai with assertions about promises.

JavaScript Testing utilities for React

Function argument validation for humans

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

WebdriverIO Assertion Library

Precondition checking utilities.

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

JavaScript Testing utilities for React

JavaScript Testing utilities for React

A tiny javascript type testing tool

tap-producing test harness for node and browsers