React & Next.js

React 19 + Next.js

• Server components by default — layout.tsx, loading.tsx, error.tsx are server components
• 'use client' only when needed — components with hooks must be client components
• No IIFEs in JSX — extract to a named component instead
• No raw HTML elements when shadcn has a component — use Button not <button>, Table not <table>, Progress not nested divs
• use* hook naming enforced
• Stable array keys — never use indices
• <Suspense> around useSearchParams()
• No Date.now() / Math.random() in render