Testing

Unit / integration

• ★ Vitest — Vite-native, Jest-compatible API, fast. The default for new TS projects.
• Jest — long-running standard; still huge install base. Vitest reads Jest tests with minimal changes.
• Bun test — built into Bun; very fast for Bun projects.
• node:test — Node's built-in runner; good for libraries that can't depend on a third-party runner.

End-to-end

• ★ Playwright — fastest, most reliable, multi-browser, traces, screenshots, codegen, component testing. Default for new E2E.
• Cypress — still hugely popular; richer dev UI; some teams prefer it for component tests.
• Puppeteer — narrower scope; mostly used for PDFs / scraping now.
• WebdriverIO — when you need real Selenium / Appium / mobile.

Component / Storybook

• ★ Storybook 9 — component workshop + visual regression + interaction tests.
• Ladle — lighter Storybook alternative built on Vite.
• Chromatic — visual regression hosted; free tier.
• Histoire — Vue-first Storybook alternative.

Mocking / fixtures

• ★ MSW (Mock Service Worker) — intercept fetch / XHR; use the same mocks in tests, dev, and Storybook.
• Mirage JS — older alternative.
• vitest-mock-extended, Faker.js, @anatine/zod-mock — fixture generation.

React-specific testing

• ★ Testing Library (@testing-library/react) — encourages user-perspective tests.
• happy-dom / jsdom — DOM simulation under Vitest/Jest.
• React Native Testing Library — RN equivalent.

Pick this if…

• Unit / integration: Vitest + Testing Library.
• E2E: Playwright.
• Component workshop: Storybook.
• Mocking network: MSW.
• Visual regression: Chromatic (or Playwright traces + Argos).