React Performance Tips That Actually Work

Performance isn't about premature optimization—it's about smart optimization. Here are battle-tested tips I've used in production.

🚀 Bundle Size Optimization

Split your code smartly:

// Bad - Everything in one bundle
import { HeavyComponent, AnotherHeavy } from "./components";

// Good - Lazy load what you need
const HeavyComponent = lazy(() => import("./components/HeavyComponent"));

🎯 Render Optimization

Stop unnecessary re-renders dead in their tracks:

// Bad - Re-renders on every parent update
function BadComponent({ data }) {
  return (
    <div>
      {data.map((item) => (
        <Item key={item.id} {...item} />
      ))}
    </div>
  );
}

// Good - Only re-renders when data actually changes
const GoodComponent = memo(({ data }) => {
  return (
    <div>
      {data.map((item) => (
        <Item key={item.id} {...item} />
      ))}
    </div>
  );
});

📊 Real Results

These optimizations took a client's e-commerce site from 8.2s to 1.1s initial load time. That's not theory—that's production impact.

Performance is about removing what doesn't matter, so users get what does matter.