react-native-expert

> **AI-consumed reference.** Optimized for Claude to read during execution. > Human-readable explanation: see [docs/architecture/HIERARCHICAL_PLANNING.md](../../../docs/architecture/HIERARCHICAL_PLANNING.md) > or [docs/getting-started/](../../../docs/getting-started/) depending on topic. # React Native Expert — Gotchas & Decisions Use Context7 for React Native/Expo docs. ## Key Decisions ```toon decisions[4]{choice,use_when}: FlatList vs FlashList,"FlashList (@shopify/flash-list) for large lists — 5-10x faster. FlatList for simple short lists" Storage hierarchy,"AsyncStorage: non-sensitive KV. SecureStore: tokens/secrets. MMKV: high-perf sync access" Expo vs bare RN,"Expo: most projects (EAS Build handles native). Bare: custom native modules required" NativeWind vs StyleSheet,"NativeWind for Tailwind familiarity. StyleSheet for performance-critical views" ``` ## Gotchas - FlatList: always set `keyExtractor`, `getItemLayout` (fixed height), `maxToRenderPerBatch`, `windowSize` - `ScrollView` inside `FlatList` or vice versa — causes layout issues. Use `SectionList` or nested FlatList with `horizontal` - `Platform.select({ ios: X, android: Y, default: Z })` — always include `default` for web - `Animated.Value` persists across renders — create in `useRef` not `useState` - `useWindowDimensions()` over `Dimensions.get()` — the hook updates on rotation - Expo: `npx expo install` for compatible package versions — `npm install` may get incompatible versions - `react-nati...