React Performance Optimization: Advanced Techniques

Why Performance Matters

Performance isn't just a technical concern—it directly impacts user experience and business metrics. Studies show that a 1-second delay in page load can reduce conversions by 7%.

Memoization Strategies

React.memo for Component Memoization

const ExpensiveComponent = React.memo(({ data }) => {
  // Only re-renders when data changes
  return <div>{/* Complex rendering */}</div>;
});

useMemo for Expensive Calculations

const sortedData = useMemo(() => {
  return data.sort((a, b) => a.value - b.value);
}, [data]);

useCallback for Function Stability

const handleClick = useCallback(() => {
  // Handler logic
}, [dependency]);

Code Splitting

Use dynamic imports to split your bundle:

const LazyComponent = lazy(() => import('./HeavyComponent'));

function App() {
  return (
    <Suspense fallback={<Loading />}>
      <LazyComponent />
    </Suspense>
  );
}

Virtual Lists for Large Data Sets

For lists with thousands of items, use virtualization:

import { useVirtualizer } from '@tanstack/react-virtual';

function VirtualList({ items }) {
  const virtualizer = useVirtualizer({
    count: items.length,
    getScrollElement: () => parentRef.current,
    estimateSize: () => 50,
  });
  
  // Render only visible items
}

Conclusion

Performance optimization is an ongoing process. Measure first, optimize what matters, and always validate improvements with real data.