React Best Practices Audit

Focused audit layer for React and Next.js. Start with the six universal checks — these are the highest-leverage bugs and appear in almost every codebase. Then route to the reference that matches the user's specific question.

Universal Checks (no exceptions — run these every time)

These six checks take seconds to scan for and catch the most common, highest-impact mistakes. Skip them only if you have already verified them in the same session.

1. Components defined inside other components They are re-created on every render. Their state resets. All memoization is lost. React.memo on them does nothing. Extract to module scope.