React is fast by default, but complex apps can slow down. Here's how to identify and fix performance issues.
Measuring Performance
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React.memo
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useMemo and useCallback
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Code Splitting
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Virtualization
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State Management
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Avoiding Common Pitfalls
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Image Optimization
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Best Practices
Measuring:
✓ Profile before optimizing
✓ Use React DevTools Profiler
✓ Set performance budgets
✓ Test on slow devices
Rendering:
✓ Use React.memo appropriately
✓ Virtualize long lists
✓ Code split routes
✓ Lazy load below-the-fold
State:
✓ Keep state close to usage
✓ Avoid unnecessary updates
✓ Use refs for non-render values
✓ Split large state objects
Conclusion
React performance optimization starts with measurement. Use the Profiler to identify slow renders, apply React.memo judiciously, virtualize long lists, and code split routes. Most importantly, don't optimize prematurely—profile first, then fix actual bottlenecks.