reviewing-performance-patterns

Unnecessary re-renders occur when components update without prop or state changes. Audit re-render behavior by tracking render counts, checking memoization decisions, and reviewing which components truly need to update. React 19 patterns help you spot and eliminate these inefficiencies.

React.memo prevents re-renders when props haven't changed; useMemo caches computed values; useCallback memoizes functions. Apply these strategically during performance audits—wrap components selectively, ensure correct dependency arrays, and leverage React Compiler benefits to avoid over-memoization.

Bundle size optimization combines code-splitting, Server Components, and lazy loading strategies. Review splitting opportunities, apply Server Components appropriately, and optimize resource preloading. This reduces initial payload and improves load performance across React 19 apps.

Server Components render on the server, reducing client-side JavaScript and improving performance. Determine which components should run server-side versus client-side, then apply Server Components appropriately within your React 19 architecture for optimal rendering and resource efficiency.

Anti-patterns include memoizing everything indiscriminately, incorrect dependency arrays, and wrapping low-cost components unnecessarily. Performance audits catch these; focus memoization on genuinely expensive renders and ensure dependencies are accurate to prevent bugs and overhead.