About Jest
Jest is the most popular JavaScript testing framework. It provides test running, assertions, mocking, and code coverage out of the box.
Key Features
- Zero config
- Snapshot testing
- Parallel execution
- Built-in mocking
- Code coverage
- Watch mode
Jest became the default JavaScript testing framework by making testing frictionless. It works out of the box with zero configuration for most projects, includes a powerful mocking system, generates code coverage reports, and runs tests in parallel for speed. Jest's snapshot testing feature captures the output of components or functions and alerts you when they change, making it easy to catch unintended regressions. The watch mode reruns only tests affected by your changes, providing fast feedback during development. Jest supports TypeScript, React, Node.js, Angular, and Vue with minimal setup.