text: README
  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.
  What is Chai?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.
  InstallationInstallation
  Node.jsNode.js
  chai is available on npm. To install it, type:
  $ npm install --save-dev chai
  BrowsersBrowsers
  You can also use it within the browser; install via npm and use the
  chai.js file found within the download. For example:
  <script src="./node_modules/chai/chai.js"></script>
  UsageUsage
  Import the library in your code, and then pick one of the styles you'd like to use - either
  assert,
  expect or
  should:
  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)Pre-Native Modules Usage (registers the chai testing style globally)
  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)Pre-Native Modules Usage (as local variables)
  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)Native Modules Usage (registers the chai testing style globally)
  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)Native Modules Usage (local import only)
  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 MochaUsage with Mocha
  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.
  PluginsPlugins
  Chai offers a robust Plugin architecture for extending Chai's assertions and interfaces.
  - Need a plugin? View the official plugin list.
  - Want to build a plugin? Read the plugin api documentation.
  - Have a plugin and want it listed? Simply add the following keywords to your package.json:
  chai-plugin
  browserif your plugin works in the browser as well as Node.js
  browser-onlyif your plugin does not work with Node.js
  Related ProjectsRelated Projects
  - chaijs / chai-docs: The chaijs.com website source code.
  - chaijs / assertion-error: Custom
  Errorconstructor thrown upon an assertion failing.
  - chaijs / deep-eql: Improved deep equality testing for Node.js and the browser.
  - chaijs / type-detect: Improved typeof detection for Node.js and the browser.
  - chaijs / check-error: Error comparison and information related utility for Node.js and the browser.
  - chaijs / loupe: Inspect utility for Node.js and browsers.
  - chaijs / pathval: Object value retrieval given a string path.
  - chaijs / get-func-name: Utility for getting a function's name for node and the browser.
  ContributingContributing
  Thank you very much for considering to contribute!
  Please make sure you follow our Code Of Conduct and we also strongly recommend reading our Contributing Guide.
  Here are a few issues other contributors frequently ran into when opening pull requests:
  - Please do not commit changes to the
  chai.jsbuild. We do it once per release.
  - Before pushing your commits, please make sure you rebase them.
  ContributorsContributors
  Please see the full Contributors Graph for our list of contributors.
  Core ContributorsCore 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.