React Native Performance Patterns

Quick Guide: Profile before optimizing -- use React Native DevTools Profiler (replaces Flipper since 0.76) and platform profilers to find actual bottlenecks. Target 60 FPS (16.67ms per frame). Understand JS thread vs UI thread: animations on the UI thread, business logic on JS. Use React.memo + useCallback for list items, FlashList for large lists, InteractionManager to defer heavy work during transitions. React Compiler (v1.0+) auto-memoizes most components -- verify before adding manual memoization. Always test in release builds; dev mode adds significant overhead.

<critical_requirements>

CRITICAL: Before Using This Skill

(You MUST profile BEFORE optimizing -- use React Native DevTools Profiler or platform tools to identify actual bottlenecks, never optimize blindly)

(You MUST test performance in RELEASE builds -- dev mode adds significant overhead that masks real performance characteristics)

(You MUST understand the JS thread vs UI thread distinction -- animations belong on the UI thread, heavy computation must be deferred with InteractionManager)

(You MUST memoize renderItem callbacks and item components for FlashList/FlatList -- inline functions break virtualization performance)

(You MUST check if React Compiler is enabled before adding manual useMemo/useCallback/React.memo -- the compiler auto-memoizes and manual hints become redundant)