🇷🇺 Русская версия (тема 05 в подготовке к интервью): 05. Performance optimization в React

From the job posting: "Understanding of performance optimization techniques in React (lazy loading, memoization, virtualization)."

High-load web app, mobile-first - performance is not optional, it's a requirement.

Interviewers will ask about real cases: "Your feed with 10k messages is lagging — what do you do?"

Checklist

• [ ] How to measure: React DevTools Profiler, Chrome Performance, Web Vitals
• [ ] Core Web Vitals: LCP, INP, CLS — what they are and how to improve them
• [ ] Causes of unnecessary re-renders
• [ ] React.memo, useMemo, useCallback - where they help, where they don't
• [ ] List virtualization (react-window, TanStack Virtual)
• [ ] Code splitting: route-based, component-based, library-based
• [ ] Bundle size: analyzer, tree shaking, import cost
• [ ] Lazy loading images, preload, prefetch
• [ ] Web Workers for heavy computations
• [ ] Debouncing / throttling in React
• [ ] Concurrent features: useTransition, useDeferredValue
• [ ] Finding memory leaks
• [ ] Layout shifts and forced synchronous layouts (reflow)
• [ ] Animations: CSS vs JS, GPU acceleration