Jest is a JavaScript testing framework designed to ensure correctness of any JavaScript codebase. It allows you to write tests with an approachable, familiar and feature-rich API that gives you results …

In your test files, Jest puts each of these methods and objects into the global environment. You don't have to require or import anything to use them. However, if you prefer explicit imports, you can do …

Note: Jest documentation uses yarn commands, but npm will also work. You can compare yarn and npm commands in the yarn docs, here. Let's get started by writing a test for a hypothetical function that …

Note: babel-jest is automatically installed when installing Jest and will automatically transform files if a babel configuration exists in your project. To avoid this behavior, you can explicitly reset the …

Need help? Jest is worked on by a team of volunteers in their spare time. You can find out ways to talk to community members below.

Jest is a universal testing platform, with the ability to adapt to any JavaScript library or framework. In this section, we'd like to link to community posts and articles about integrating Jest into popular JS libraries.

You can cherry pick specific features of Jest and use them as standalone packages. Here's a list of the available packages:

See React: Function and Class Components. Reminders that with Class components, we expect Jest to be used to test props and not methods directly. Now let's use React's test renderer and Jest's …

Jest はシンプルさを重視した、快適な JavaScript テスティングフレームワークです。 Babel, TypeScript, Node, React, Angular, Vue …… これらに限らず、様々なフレームワークを利用したプ …

Jest adds the inlineSnapshot string argument to the matcher in the test file (instead of an external .snap file) the first time that the test runs. Check out the section on Inline Snapshots for more info.