Vitest Best Practices

Vitest 5-compatible testing guide with 46 rules across 8 categories. Vitest 5 requires Node.js 22.12+ and Vite 6.4+; Vitest 4.1 remains on backport support.

When to Apply

Reference these guidelines when:

• Writing new Vitest tests
• Debugging flaky or slow tests
• Setting up test configuration
• Reviewing test code in PRs
• Migrating from Jest to Vitest
• Optimizing CI/CD test performance

Jest-specific APIs and configuration outside documented migration differences are out of scope; use Jest's own documentation for tests that still run under Jest.

Rule Categories by Priority