React Performance - Fundamentals and Common Challenges | Gurzu

In this episode of knowledge ketchup, Dawa gives an overview of React performance fundamentals, common challenges, and practical tips to build faster, more efficient applications.

Transcript

1. REACT PERFORMANCE PERFORMANCE FUNDAMENTALS AND COMMON CHALLENGES
2. Why Performance Matters • Laggy user experience degrades engagement and satisfaction • Negatively affects Core Web Vitals, harming SEO performance • Leads to excessive memory consumption, increasing risk of crashes
3. Common Performance Pitfalls Frequent state and prop updates trigger unnecessary re-renders Too many nested components make the app slower and harder to manage Inefficient DOM manipulations slow down rendering and responsiveness
4. Problematic Code Example (All 3 Issues Combined) Unnecessary Re-renders – Updating unrelated state like text causes components like Child and GrandChild to re-render without any real change. Re-rendering during frequent actions like typing triggers extra DOM updates, making the interface slow and unresponsive.
5. React.memo prevents Child and GrandChild from re-rendering when only text changes. Re-renders only happen when count changes. What's Improved Here? Reduce Unnecessary re-render React.memo(): Prevents re-renders of functional components if props haven't changed • useMemo(): Caches the result of an expensive computation and only recalculates it when its dependencies change, helping prevent unnecessary recalculations on every render. useCallback(): Returns a memoized version of a function that only changes if its dependencies change, preventing unnecessary re-creations of functions on re-renders—useful when passing callbacks to optimized child components.
6. Optimizing Data Fetching & State Management Virtualization / Windowing – Improve performance by rendering only the list items currently visible on the screen (not the entire list), using libraries like react-window or react-virtualized Efficient State Updates – Improve app performance by updating state immutably, batching multiple updates together, and keeping shared state to a minimum. Data Fetching Libraries – Use tools like React Query or SWR to automatically cache data and keep it updated with the server, so your app stays fast and shows fresh information without extra work.
7. Code Optimization & Bundling Code Splitting & Lazy Loading: Use React.lazy + Suspense for route-based or component-based loading Bundle Size Reduction: Remove unused code, enable tree-shaking, compress assets
8. Throttling & Debouncing: Reduce function calls for scroll, resize, and input events React Fragments: Use <></> or <React.Fragment> to group without adding extra DOM nodes Web Workers: Offload heavy calculations to avoid blocking main thread Intersection Observer :Detects when elements enter the viewport, useful for lazy loading, infinite scroll, and triggering animations efficiently. Other Optimization Techniques
9. Monitoring and Profiling React DevTools Profiler: Analyze component render times Browser Developer Tools: Inspect network usage, script execution, layout paint times
10. Thank you very much! PRESENTED BY DAWA GYALCHEN SHERPA