Optimization involves reducing bundle size, improving runtime speed, and enhancing perceived performance. Key strategies:

  • Code Splitting: Load code on demand (route-based or component-based) using React.lazy and Suspense.
  • Memoization: Prevent unnecessary re-renders using React.memo, useMemo, useCallback.
  • Bundle Analysis: Use tools (webpack-bundle-analyzer) to find large dependencies.
  • Tree Shaking: Ensure unused code is removed by the bundler.
  • Virtualization: Render only visible items in long lists/tables (react-window).
  • Optimize Context: Split contexts, memoize values to avoid excessive re-renders.
  • SSR/SSG: Improve initial load time with server-side rendering or static generation.
  • Profiling: Use React DevTools Profiler to find bottlenecks.

Simplified Example (React.memo):

import React from 'react';
// Assume UserProfile makes an expensive calculation or renders complex UI
function UserProfile({ user }) { console.log(`Rendering profile for ${user.name}`); // ... complex rendering ... return <div>{user.name}</div>;
}
// Memoize the component: It will only re-render if the 'user' prop changes reference or value.
const MemoizedUserProfile = React.memo(UserProfile);
// Usage: <MemoizedUserProfile user={currentUser} />