Vitest

A modern testing framework that shares Vite's config and gives you instant HMR in watch mode. You get a Jest-compatible API with native ESM support, so migration is usually just swapping `jest` for `vi`. Recent versions added control-flow hooks like `aroundEach`, better test metadata with tags, and real browser testing through Playwright. Coverage works out of the box with v8, snapshots update inline, and TypeScript needs zero extra config. If you're already using Vite, this is the obvious choice. If you're not, it's still faster than Jest and the browser mode actually runs tests in Chrome or Firefox instead of simulating DOM behavior.

Install to Claude Code

npx -y skills add itechmeat/llm-code --skill vitest --agent claude-code