![\"ChaiJS\"](\"http://chaijs.com/img/chai-logo.png\"){kind=logo}
\n \n \n chai\n
\n \n \n Chai is a BDD / TDD assertion library for node and the browser that can be delightfully paired with any javascript testing framework.\n
\n\n\n\nFor more information or to download plugins, view the [documentation](http://chaijs.com).\n\n## What is Chai?\n\nChai 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.\n\n## Installation\n\n### Node.js\n\n`chai` is available on [npm](http://npmjs.org). To install it, type:\n\n $ npm install --save-dev chai\n\n### Browsers\n\nYou can also use it within the browser; install via npm and use the `chai.js` file found within the download. For example:\n\n```html\n\n```\n\n## Usage\n\nImport the library in your code, and then pick one of the styles you'd like to use - either `assert`, `expect` or `should`:\n\n```js\nvar chai = require('chai'); \nvar assert = chai.assert; // Using Assert style\nvar expect = chai.expect; // Using Expect style\nvar should = chai.should(); // Using Should style\n```\n\n### Pre-Native Modules Usage (_registers the chai testing style globally_)\n\n```js\nrequire('chai/register-assert'); // Using Assert style\nrequire('chai/register-expect'); // Using Expect style\nrequire('chai/register-should'); // Using Should style\n```\n\n### Pre-Native Modules Usage (_as local variables_)\n\n```js\nconst { assert } = require('chai'); // Using Assert style\nconst { expect } = require('chai'); // Using Expect style\nconst { should } = require('chai'); // Using Should style\nshould(); // Modifies `Object.prototype`\n\nconst { expect, use } = require('chai'); // Creates local variables `expect` and `use`; useful for plugin use\n```\n\n### Native Modules Usage (_registers the chai testing style globally_)\n\n```js\nimport 'chai/register-assert'; // Using Assert style\nimport 'chai/register-expect'; // Using Expect style\nimport 'chai/register-should'; // Using Should style\n```\n\n### Native Modules Usage (_local import only_)\n\n```js\nimport { assert } from 'chai'; // Using Assert style\nimport { expect } from 'chai'; // Using Expect style\nimport { should } from 'chai'; // Using Should style\nshould(); // Modifies `Object.prototype`\n```\n\n### Usage with Mocha\n\n```bash\nmocha spec.js -r chai/register-assert # Using Assert style\nmocha spec.js -r chai/register-expect # Using Expect style\nmocha spec.js -r chai/register-should # Using Should style\n```\n\n[Read more about these styles in our docs](http://chaijs.com/guide/styles/).\n\n## Plugins\n\nChai offers a robust Plugin architecture for extending Chai's assertions and interfaces.\n\n- Need a plugin? View the [official plugin list](http://chaijs.com/plugins).\n- Want to build a plugin? Read the [plugin api documentation](http://chaijs.com/guide/plugins/).\n- Have a plugin and want it listed? Simply add the following keywords to your package.json:\n - `chai-plugin`\n - `browser` if your plugin works in the browser as well as Node.js\n - `browser-only` if your plugin does not work with Node.js\n\n### Related Projects\n\n- [chaijs / chai-docs](https://github.com/chaijs/chai-docs): The chaijs.com website source code.\n- [chaijs / assertion-error](https://github.com/chaijs/assertion-error): Custom `Error` constructor thrown upon an assertion failing.\n- [chaijs / deep-eql](https://github.com/chaijs/deep-eql): Improved deep equality testing for Node.js and the browser.\n- [chaijs / type-detect](https://github.com/chaijs/type-detect): Improved typeof detection for Node.js and the browser.\n- [chaijs / check-error](https://github.com/chaijs/check-error): Error comparison and information related utility for Node.js and the browser.\n- [chaijs / loupe](https://github.com/chaijs/loupe): Inspect utility for Node.js and browsers.\n- [chaijs / pathval](https://github.com/chaijs/pathval): Object value retrieval given a string path.\n\n### Contributing\n\nThank you very much for considering to contribute!\n\nPlease 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).\n\nHere are a few issues other contributors frequently ran into when opening pull requests:\n\n- Please do not commit changes to the `chai.js` build. We do it once per release.\n- Before pushing your commits, please make sure you [rebase](https://github.com/chaijs/chai/blob/master/CONTRIBUTING.md#pull-requests) them.\n\n### Contributors\n\nPlease see the full\n[Contributors Graph](https://github.com/chaijs/chai/graphs/contributors) for our\nlist of contributors.\n\n### Core Contributors\n\nFeel free to reach out to any of the core contributors with your questions or\nconcerns. We will do our best to respond in a timely manner.\n\n[](https://github.com/logicalparadox)\n[](https://github.com/vesln)\n[](https://github.com/keithamus)\n[](https://github.com/lucasfcosta)\n[](https://github.com/meeber)\n","_attachments":{},"homepage":"http://chaijs.com","bugs":{"url":"https://github.com/chaijs/chai/issues"},"license":"MIT"}