Jest

Execution Commands

Run Jest tests with precision — from a single test file to your entire suite. Learn to use watch mode, filter by name, run in parallel, and control test execution for fast feedback.

10 commands

Pro Tips

Use 'jest --watch' for TDD workflow — it re-runs only tests affected by changed files.

Run a single test: 'jest path/to/test.ts -t "test name pattern"' to focus on what you're debugging.

Use 'jest --bail' to stop on first failure — saves time in CI when you just need to know if something broke.

Common Mistakes

Running 'jest' without '--runInBand' runs tests in parallel by default. Tests with shared state may flake.

Jest caches transforms by default. If tests behave oddly after config changes, clear with 'jest --clearCache'.

Commands

Run all tests

$ jest

Run all test files.

Watch mode

$ jest --watch

Watch files for changes and rerun tests.

Watch all tests

$ jest --watchAll

Watch mode that reruns all tests.

Run specific file

$ jest path/to/test.spec.js

Run tests from a specific file.

Run by pattern

$ jest -t 'login'

Run tests matching name pattern.

Generate coverage

$ jest --coverage

Run tests with coverage report.

Verbose output

$ jest --verbose

Display detailed test results.

Changed files only

$ jest -o

Run tests for changed files only.

Only changed tests

$ jest --onlyChanged

Run tests related to changed files.

Serial execution

$ jest --runInBand

Run tests serially in current process.