/react-native-dev

name: react-native-dev
description: |
  React Native and Expo development guide covering components, styling, animations, navigation,
  state management, forms, networking, performance optimization, testing, native capabilities,
  and engineering (project structure, deployment, SDK upgrades, CI/CD).
  Use when: building React Native or Expo apps, implementing animations or native UI, managing
  state, fetching data, writing tests, optimizing performance, deploying to App Store/Play Store,
  setting up CI/CD, upgrading Expo SDK, or configuring Tailwind/NativeWind.
license: MIT
metadata:
  version: "1.0.0"
  category: mobile
  sources:
    - expo/skills by Expo (https://github.com/expo/skills) — Native UI, navigation, and animation patterns
    - Expo documentation (docs.expo.dev)
    - React Native documentation (reactnative.dev)
    - EAS (Expo Application Services) documentation

React Native & Expo Development Guide

A practical guide for building production-ready React Native and Expo applications. Covers UI, animations, state, testing, performance, and deployment.

References

Consult these resources as needed:

• [references/navigation.md](references/navigation.md) — Expo Router: Stack, Tabs, NativeTabs (`headerLargeTitle`, `headerBackButtonDisplayMode`), links, modals, sheets, context menus
• [references/components.md](references/components.md) — FlashList patterns, `expo-image`, safe areas (`contentInsetAdjustmentBehavior`), native controls, blur/glass effects, storage
• [references/styling.md](references/styling.md) — StyleSheet, NativeWind/Tailwind, platform styles, theming, dark mode
• [references/animations.md](references/animations.md) — Reanimated 3: entering/exiting, shared values, gestures, scroll-driven
• [references/state-management.md](references/state-management.md) — Zustand (selectors, persist), Jotai (atoms, derived), React Query, Context
• [references/forms.md](references/forms.md) — React Hook Form + Zod: validation, multi-step, dynamic arrays
• [references/networking.md](references/networking.md) — fetch wrapper, React Query (optimistic updates), auth tokens, offline, API routes, webhooks
• [references/performance.md](references/performance.md) — Profiling workflow, FlashList + `memo`, bundle analysis, TTI, memory leaks, animation perf
• [references/testing.md](references/testing.md) — Jest, React Native Testing Library, E2E with Maestro
• [references/native-capabilities.md](references/native-capabilities.md) — Camera, location, permissions (`use*Permissions` hooks), haptics, notifications, biometrics
• [references/engineering.md](references/engineering.md) — Project layout (`components/ui/`, `stores/`, `services/`), path aliases, SDK upgrades, EAS build/submit, CI/CD, DOM components

Quick Reference

Component Preferences

| Purpose | Use | Instead of | |---------|-----|------------| | Lists | `FlashList` (`@shopify/flash-list`) + `memo` items | `FlatList` (no view recycling) | | Images | `expo-image` | RN `<Image>` (no cache, no WebP) | | Press | `Pressable` | `TouchableOpacity` (legacy) | | Audio | `expo-audio` | `expo-av` (deprecated) | | Video | `expo-video` | `expo-av` (deprecated) | | Animations | Reanimated 3 | RN Animated API (limited) | | Gestures | Gesture Handler | PanResponder (legacy) | | Platform check | `process.env.EXPO_OS` | `Platform.OS` | | Context | `React.use()` | `React.useContext()` (React 18) | | Safe area scroll | `contentInsetAdjustmentBehavior="automatic"` | `<SafeAreaView>` | | SF Symbols | `expo-image` with `source="sf:name"` | `expo-symbols` |

Scaling Up

| Situation | Consider | |-----------|----------| | Long lists with scroll jank | Virtualized list libraries (e.g. FlashList) | | Want Tailwind-style classes | NativeWind v4 | | High-frequency storage reads | Sync-based storage (e.g. MMKV) | | New project with Expo | Expo Router over bare React Navigation |

State Management

| State Type | Solution | |------------|----------| | Local UI state | `useState` / `useReducer` | | Shared app state | Zustand or Jotai | | Server / async data | React Query | | Form state | React Hook Form + Zod |

Performance Priorities

| Priority | Issue | Fix | |----------|-------|-----| | CRITICAL | Long list jank | `FlashList` + memoized items | | CRITICAL | Large bundle | Avoid barrel imports, enable R8 | | HIGH | Too many re-renders | Zustand selectors, React Compiler | | HIGH | Slow startup | Disable bundle compression, native nav | | MEDIUM | Animation drops | Only animate `transform`/`opacity` |

New Project Init

# 1. Create project
npx create-expo-app@latest my-app --template blank-typescript
cd my-app

# 2. Install Expo Router + core deps
npx expo install expo-router react-native-safe-area-context react-native-screens

# 3. (Optional) Common extras
npx expo install expo-image react-native-reanimated react-native-gesture-handler

Then configure:

1. Set entry point in `package.json`: `"main": "expo-router/entry"` 2. Add scheme in `app.json`: `"scheme": "my-app"` 3. Delete `App.tsx` and `index.ts` 4. Create `app/_layout.tsx` as root Stack layout 5. Create `app/(tabs)/_layout.tsx` for tab navigation 6. Create route files in `app/(tabs)/` (see [navigation.md](references/navigation.md))

For web support, also install: `npx expo install react-native-web react-dom @expo/metro-runtime`

Core Principles

**Consult references before writing**: when implementing navigation, lists, networking, or project setup, read the matching reference file above for patterns and pitfalls.

**Try Expo Go first** (`npx expo start`). Custom builds (`eas build`) only needed when using local Expo modules, Apple targets, or third-party native modules not in Expo Go.

**Conditional rendering**: use `{count > 0 && <Text />}` not `{count && <Text />}` (renders "0").

**Animation rule**: only animate `transform` and `opacity` — GPU-composited, no layout thrash.

**Imports**: always import directly from source, not barrel files —