<h1 align=center> <a href="http://chaijs.com" title="Chai Documentation"> <img alt="ChaiJS" src="http://chaijs.com/img/chai-logo.png"> </a> <br> chai </h1> <p align=center> Chai is a BDD / TDD assertion library for <a href="http://nodejs.org">node</a> and the browser that can be delightfully paired with any javascript testing framework. </p> <p align=center> <a href="./LICENSE"> <img alt="license:mit" src="https://img.shields.io/badge/license-mit-green.svg?style=flat-square" /> </a> <a href="https://github.com/chaijs/chai/releases"> <img alt="tag:?" src="https://img.shields.io/github/tag/chaijs/chai.svg?style=flat-square" /> </a> <a href="https://www.npmjs.com/package/chai"> <img alt="node:?" src="https://img.shields.io/badge/node-%3E=4.0-blue.svg?style=flat-square" /> </a> <br/> <a href="https://saucelabs.com/u/chaijs"> <img alt="Selenium Test Status" src="https://saucelabs.com/browser-matrix/chaijs.svg" /> </a> <br/> <a href="https://www.npmjs.com/packages/chai"> <img alt="downloads:?" src="https://img.shields.io/npm/dm/chai.svg?style=flat-square" /> </a> <a href="https://travis-ci.org/chaijs/chai"> <img alt="build:?" src="https://img.shields.io/travis/chaijs/chai/master.svg?style=flat-square" /> </a> <a href="https://codecov.io/gh/chaijs/chai"> <img alt="coverage:?" src="https://img.shields.io/codecov/c/github/chaijs/chai.svg?style=flat-square" /> </a> <a href=""> <img alt="devDependencies:?" src="https://img.shields.io/david/chaijs/chai.svg?style=flat-square" /> </a> <br/> <a href="https://chai-slack.herokuapp.com/"> <img alt="Join the Slack chat" src="https://img.shields.io/badge/slack-join%20chat-E2206F.svg?style=flat-square" /> </a> <a href="https://gitter.im/chaijs/chai"> <img alt="Join the Gitter chat" src="https://img.shields.io/badge/gitter-join%20chat-D0104D.svg?style=flat-square" /> </a> <a href="https://opencollective.com/chaijs"> <img alt="OpenCollective Backers" src="https://opencollective.com/chaijs/backers/badge.svg?style=flat-square" /> </a> </p> For more information or to download plugins, view the [documentation](http://chaijs.com). ## What is Chai? Chai is an _assertion library_, similar to Node's built-in `assert`. It makes testing much easier by giving you lots of assertions you can run against your code. ## Installation ### Node.js `chai` is available on [npm](http://npmjs.org). To install it, type: $ npm install --save-dev chai ### Browsers You can also use it within the browser; install via npm and use the `chai.js` file found within the download. For example: ```html <script src="./node_modules/chai/chai.js"></script> ``` ## Usage Import the library in your code, and then pick one of the styles you'd like to use - either `assert`, `expect` or `should`: ```js var chai = require('chai'); var assert = chai.assert; // Using Assert style var expect = chai.expect; // Using Expect style var should = chai.should(); // Using Should style ``` ### Pre-Native Modules Usage (_registers the chai testing style globally_) ```js require('chai/register-assert'); // Using Assert style require('chai/register-expect'); // Using Expect style require('chai/register-should'); // Using Should style ``` ### Pre-Native Modules Usage (_as local variables_) ```js const { assert } = require('chai'); // Using Assert style const { expect } = require('chai'); // Using Expect style const { should } = require('chai'); // Using Should style should(); // Modifies `Object.prototype` const { expect, use } = require('chai'); // Creates local variables `expect` and `use`; useful for plugin use ``` ### Native Modules Usage (_registers the chai testing style globally_) ```js import 'chai/register-assert'; // Using Assert style import 'chai/register-expect'; // Using Expect style import 'chai/register-should'; // Using Should style ``` ### Native Modules Usage (_local import only_) ```js import { assert } from 'chai'; // Using Assert style import { expect } from 'chai'; // Using Expect style import { should } from 'chai'; // Using Should style should(); // Modifies `Object.prototype` ``` ### Usage with Mocha ```bash mocha spec.js -r chai/register-assert # Using Assert style mocha spec.js -r chai/register-expect # Using Expect style mocha spec.js -r chai/register-should # Using Should style ``` [Read more about these styles in our docs](http://chaijs.com/guide/styles/). ## Plugins Chai offers a robust Plugin architecture for extending Chai's assertions and interfaces. - Need a plugin? View the [official plugin list](http://chaijs.com/plugins). - Want to build a plugin? Read the [plugin api documentation](http://chaijs.com/guide/plugins/). - Have a plugin and want it listed? Simply add the following keywords to your package.json: - `chai-plugin` - `browser` if your plugin works in the browser as well as Node.js - `browser-only` if your plugin does not work with Node.js ### Related Projects - [chaijs / chai-docs](https://github.com/chaijs/chai-docs): The chaijs.com website source code. - [chaijs / assertion-error](https://github.com/chaijs/assertion-error): Custom `Error` constructor thrown upon an assertion failing. - [chaijs / deep-eql](https://github.com/chaijs/deep-eql): Improved deep equality testing for Node.js and the browser. - [chaijs / type-detect](https://github.com/chaijs/type-detect): Improved typeof detection for Node.js and the browser. - [chaijs / check-error](https://github.com/chaijs/check-error): Error comparison and information related utility for Node.js and the browser. - [chaijs / loupe](https://github.com/chaijs/loupe): Inspect utility for Node.js and browsers. - [chaijs / pathval](https://github.com/chaijs/pathval): Object value retrieval given a string path. - [chaijs / get-func-name](https://github.com/chaijs/get-func-name): Utility for getting a function's name for node and the browser. ### Contributing Thank you very much for considering to contribute! Please make sure you follow our [Code Of Conduct](https://github.com/chaijs/chai/blob/master/CODE_OF_CONDUCT.md) and we also strongly recommend reading our [Contributing Guide](https://github.com/chaijs/chai/blob/master/CONTRIBUTING.md). Here are a few issues other contributors frequently ran into when opening pull requests: - Please do not commit changes to the `chai.js` build. We do it once per release. - Before pushing your commits, please make sure you [rebase](https://github.com/chaijs/chai/blob/master/CONTRIBUTING.md#pull-requests) them. ### Contributors Please see the full [Contributors Graph](https://github.com/chaijs/chai/graphs/contributors) for our list of contributors. ### Core Contributors Feel free to reach out to any of the core contributors with your questions or concerns. We will do our best to respond in a timely manner. [](https://github.com/logicalparadox) [](https://github.com/vesln) [](https://github.com/keithamus) [](https://github.com/lucasfcosta) [](https://github.com/meeber)