React Performance Optimization Techniques

Performance optimization is crucial for delivering a great user experience. Let's explore various techniques to optimize React applications.

Component Optimization

Memoization

// Use React.memo for functional components
const MemoizedComponent = React.memo(({ data }) => {
  return <div>{data}</div>;
});

// Use useMemo for expensive calculations
const memoizedValue = useMemo(() => computeExpensiveValue(a, b), [a, b]);

// Use useCallback for function props
const memoizedCallback = useCallback(() => {
  doSomething(a, b);
}, [a, b]);

Code Splitting

Route-based Code Splitting

const LazyComponent = lazy(() => import("./LazyComponent"));

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

Component-level Code Splitting

const HeavyComponent = lazy(() => import("./HeavyComponent"));

Virtualization

List Virtualization

import { FixedSizeList } from "react-window";

function VirtualizedList({ items }) {
  return (
    <FixedSizeList
      height={400}
      width={300}
      itemCount={items.length}
      itemSize={35}
    >
      {({ index, style }) => <div style={style}>{items[index]}</div>}
    </FixedSizeList>
  );
}

State Management

Local State vs Global State

• Use local state for component-specific data
• Use global state only when necessary
• Consider using Context API for medium-scale state

Conclusion

Key takeaways for React performance optimization:

1. Implement proper memoization
2. Use code splitting for large applications
3. Apply virtualization for long lists
4. Optimize state management
5. Monitor performance metrics