react-performance-optimization

Slow rendering in React typically stems from unnecessary re-renders. Use React.memo to prevent child components from re-rendering when props haven't changed, useMemo to cache expensive computations, and useCallback to maintain stable function references across renders. These memoization techniques eliminate redundant renders and speed up component updates.

React.memo wraps entire components to skip re-renders when props are shallow-equal, ideal for expensive child components. useMemo caches the result of expensive computations within a component, returning the same value until dependencies change. Use React.memo for component-level optimization and useMemo for computation-level caching within render functions.

Code splitting with React.lazy and Suspense dynamically imports components only when needed, shrinking your initial bundle. Wrap lazy-loaded components in Suspense boundaries to display fallback UI while loading. This defers non-critical code, enabling faster first paint and improving Time to Interactive metrics.

Virtualization renders only visible list items in the viewport, dramatically reducing DOM nodes for large datasets. Combined with memoization of list item components, this technique prevents lag when scrolling tables and lists with thousands of rows, maintaining 60 FPS performance even with heavy data.

No. Memoization adds overhead and should target demonstrable bottlenecks. Profile first with React DevTools Profiler to identify slow renders. Prioritize memoization for expensive child components with frequent parent updates, pure components handling large datasets, or list items in virtualized containers.

Yes. These techniques complement each other: code splitting reduces initial bundle and defer load, while memoization prevents unnecessary re-renders of loaded components. Together they address both startup latency and runtime smoothness, creating faster initial experiences and responsive interactions.