Optimizing React Performance

Performance optimization is crucial for delivering great user experiences. Let's explore practical React optimization techniques.

React.memo

Use React.memo to prevent unnecessary re-renders:

const ExpensiveComponent = React.memo(({ data }) => {
  return <div>{/* Complex rendering */}</div>;
});

useMemo and useCallback

Cache expensive computations and function references:

const expensiveValue = useMemo(() => {
  return computeExpensiveValue(data);
}, [data]);

const handleClick = useCallback(() => {
  doSomething();
}, []);

Code Splitting

Split your bundle for faster initial loads:

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

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

Virtualization

For long lists, use virtualization:

import { FixedSizeList } from 'react-window';

<FixedSizeList
  height={600}
  itemCount={items.length}
  itemSize={50}
  width="100%"
>
  {({ index, style }) => (
    <div style={style}>{items[index]}</div>
  )}
</FixedSizeList>

Performance Monitoring

Use React DevTools Profiler to identify bottlenecks:

1. Record a performance profile 2. Identify components with long render times 3. Optimize or memoize as needed

Best Practices

• Measure before optimizing
• Use React DevTools Profiler
• Optimize only when necessary
• Consider user experience impact

Performance optimization is an ongoing process. Start with the biggest wins and iterate.