Common React Native Mistakes That Hurt Production Apps

Mistake #1: Not Handling Network Failures

Mobile networks are unreliable. Apps must gracefully handle offline states, timeouts, and partial failures. I've seen production apps crash because they assumed network requests always succeed.

typescript

// ❌ Bad: No error handling
async function fetchUserData() {
  const response = await fetch('/api/user');
  const data = await response.json();
  setUser(data);
}

// ✅ Good: Comprehensive error handling
async function fetchUserData() {
  try {
    const controller = new AbortController();
    const timeoutId = setTimeout(() => controller.abort(), 10000);
    
    const response = await fetch('/api/user', {
      signal: controller.signal,
    });
    
    clearTimeout(timeoutId);
    
    if (!response.ok) {
      throw new Error(`HTTP ${response.status}: ${response.statusText}`);
    }
    
    const data = await response.json();
    setUser(data);
    setError(null);
  } catch (err) {
    if (err.name === 'AbortError') {
      setError('Request timeout - please try again');
    } else if (!navigator.onLine) {
      setError('No internet connection');
    } else {
      setError('Failed to load user data');
      Sentry.captureException(err);
    }
  }
}

Mistake #2: Ignoring Android Back Button

Android's back button behavior must be explicitly handled. Failing to do so creates a frustrating user experience and app store rejections.

typescript

import { BackHandler } from 'react-native';

function useBackHandler(handler: () => boolean) {
  useEffect(() => {
    // Return true to prevent default back behavior
    BackHandler.addEventListener('hardwareBackPress', handler);
    
    return () => {
      BackHandler.removeEventListener('hardwareBackPress', handler);
    };
  }, [handler]);
}

// Example: Confirm before exiting
function App() {
  useBackHandler(() => {
    if (hasUnsavedChanges) {
      Alert.alert(
        'Discard changes?',
        'You have unsaved changes.',
        [
          { text: 'Cancel', style: 'cancel' },
          { text: 'Discard', onPress: () => navigation.goBack() },
        ]
      );
      return true; // Prevent default
    }
    return false; // Allow default
  });
}

Mistake #3: Memory Leaks from Animations

Animated values that aren't cleaned up cause memory leaks and performance degradation over time. This is especially problematic in long-running apps.

Leak Source	Impact	Fix
Animated.Value listeners	Memory accumulation	Remove listeners in cleanup
Running animations on unmount	Crashes, warnings	Stop animations in useEffect cleanup
Reanimated worklets	Native memory leaks	Cancel animations properly

typescript

// ❌ Bad: Animation continues after unmount
function FadeInView({ children }) {
  const fadeAnim = useRef(new Animated.Value(0)).current;
  
  useEffect(() => {
    Animated.timing(fadeAnim, {
      toValue: 1,
      duration: 1000,
      useNativeDriver: true,
    }).start();
  }, []);
  
  return <Animated.View style={{ opacity: fadeAnim }}>{children}</Animated.View>;
}

// ✅ Good: Animation cleaned up on unmount
function FadeInView({ children }) {
  const fadeAnim = useRef(new Animated.Value(0)).current;
  
  useEffect(() => {
    const animation = Animated.timing(fadeAnim, {
      toValue: 1,
      duration: 1000,
      useNativeDriver: true,
    });
    
    animation.start();
    
    return () => {
      animation.stop();
      fadeAnim.setValue(0);
    };
  }, [fadeAnim]);
  
  return <Animated.View style={{ opacity: fadeAnim }}>{children}</Animated.View>;
}

Mistake #4: Not Testing on Real Devices

Simulators/emulators don't represent real-world conditions. Always test on physical devices, especially lower-end Android devices which represent the majority of users globally.

Test Scenario	Why It Matters	Real Device Only
Camera/Sensors	Hardware integration bugs	✓
Low memory	Crashes on budget devices	✓
Slow network	Loading states, timeouts	✓
Push notifications	User engagement critical	✓

Mistake #5: Blocking the Main Thread

Heavy computations on the JS thread freeze the UI. Move expensive work to background threads or native modules:

typescript

// ❌ Bad: Blocks UI thread
function processLargeDataset(data: any[]) {
  const result = data.map(item => {
    // Complex computation
    return expensiveTransform(item);
  });
  setProcessedData(result);
}

// ✅ Good: Use InteractionManager
import { InteractionManager } from 'react-native';

function processLargeDataset(data: any[]) {
  InteractionManager.runAfterInteractions(() => {
    const result = data.map(item => expensiveTransform(item));
    setProcessedData(result);
  });
}

// ✅ Better: Use react-native-worklets or web workers
import { useRunOnJS } from 'react-native-reanimated';

function processInBackground(data: any[]) {
  'worklet';
  const result = data.map(item => expensiveTransform(item));
  useRunOnJS(setProcessedData)(result);
}

React Native Production Mistakes Infographic

Prevention is Better Than Cure

These mistakes are preventable with proper code reviews, testing, and monitoring. Implement error boundaries, use crash reporting (Sentry/Crashlytics), and monitor performance metrics in production. Your users will thank you.