react-native-stability-reliability

name	React Native Stability & Reliability
description	Technical rules for a stable, crash-free, and performant React Native app.

🛡️ React Native Stability & Reliability

To ensure the application remains stable in production, you must strictly follow these technical rules.

1. Error Boundaries & Crash Prevention

• Never let an unhandled JS exception crash the app (White Screen of Death).
• Wrap major navigators and complex screens in ErrorBoundary components.
• Always use try/catch for async/await operations, particularly when interacting with native modules (like FileSystem, SecureStore, Camera).

2. Memory Leak Prevention

• Clean up listeners: Whenever you subscribe to an event (Socket.io, AppState, Keyboard, Dimensions, EventBus), you MUST return a cleanup function in your useEffect.

useEffect(() => {
  const subscription = AppState.addEventListener('change', handleAppStateChange);
  return () => {
    subscription.remove(); // MANDATORY CLEANUP
  };
}, []);

• Avoid closures that trap large objects in memory.

3. Secure Data Storage

• Never store sensitive data (tokens, passwords, PII) in AsyncStorage.
• Always use expo-secure-store for authentication tokens and sensitive user preferences.

4. Network & Offline Resilience

• Do not assume the network is always available.
• Always provide a timeout for API requests (handled globally via Axios/apiFetch configuration).
• Use React Query's staleTime and cacheTime intelligently to reduce unnecessary background fetches.
• Display fallback UI (Skeletons or offline indicators) when data cannot be fetched.

5. Render Performance

• Avoid defining functions inside the render method of FlatLists.
• Always extract renderItem and keyExtractor outside the component or wrap them in useCallback.
• Use memo for complex list items to prevent re-rendering the entire list when a single item changes.
• Beware of StyleSheet.flatten or passing inline objects {} to deeply nested components as it breaks referential equality.

6. Deep Linking & Navigation Safety

• Always handle undefined routes gracefully.
• Validate parameters received from deep links before using them (e.g., using Zod) as they can be malformed or malicious.