chai

Chai is a BDD / TDD assertion library for node and the browser that can be delightfully paired with any javascript testing framework.

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 ``` ## 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 import { assert } from 'chai'; // Using Assert style import { expect } from 'chai'; // Using Expect style import { should } from 'chai'; // Using Should style ``` ### Register 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 ``` ### Import assertion styles as local variables ```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` import { expect, use } from 'chai'; // Creates local variables `expect` and `use`; useful for plugin use ``` ### 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 / 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. ### 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. [![Jake Luer](https://avatars3.githubusercontent.com/u/58988?v=3&s=50)](https://github.com/logicalparadox) [![Veselin Todorov](https://avatars3.githubusercontent.com/u/330048?v=3&s=50)](https://github.com/vesln) [![Keith Cirkel](https://avatars3.githubusercontent.com/u/118266?v=3&s=50)](https://github.com/keithamus) [![Lucas Fernandes da Costa](https://avatars3.githubusercontent.com/u/6868147?v=3&s=50)](https://github.com/lucasfcosta) [![Grant Snodgrass](https://avatars3.githubusercontent.com/u/17260989?v=3&s=50)](https://github.com/meeber)

	Stars	Issues	Version	Updated	Created
assert			2.1.0	8 months ago	13 years ago
chai	8,064	93	5.1.0	2 months ago	12 years ago
jest	43,581	366	29.7.0	7 months ago	12 years ago
rewire	3,070	51	7.0.0	8 months ago	12 years ago
should	1,901	11	13.2.3	6 years ago	13 years ago
sinon	9,557	42	17.0.1	6 months ago	13 years ago

assert vs chai vs jest vs rewire vs should vs sinon

Downloads in past1 Month3 Months6 Months1 Year2 Years5 YearsAll time

Stats

Popular Searches

Sick of boring JavaScript newsletters?

Downloads in past