React Native Architecture

React Native Architecture

Production-ready patterns for React Native development with Expo, including navigation, state management, native modules, and offline-first architecture.

When to Use This Skill

• Starting a new React Native or Expo project
• Implementing complex navigation patterns
• Integrating native modules and platform APIs
• Building offline-first mobile applications
• Optimizing React Native performance
• Setting up CI/CD for mobile releases

Core Concepts

1. Project Structure

src/
├── app/                    # Expo Router screens
│   ├── (auth)/            # Auth group
│   ├── (tabs)/            # Tab navigation
│   └── _layout.tsx        # Root layout
├── components/
│   ├── ui/                # Reusable UI components
│   └── features/          # Feature-specific components
├── hooks/                 # Custom hooks
├── services/              # API and native services
├── stores/                # State management
├── utils/                 # Utilities
└── types/                 # TypeScript types

2. Expo vs Bare React Native

Quick Start

# Create new Expo project
npx create-expo-app@latest my-app -t expo-template-blank-typescript

# Install essential dependencies
npx expo install expo-router expo-status-bar react-native-safe-area-context
npx expo install @react-native-async-storage/async-storage
npx expo install expo-secure-store expo-haptics

// app/_layout.tsx
import { Stack } from 'expo-router';
import { ThemeProvider } from '@/providers/ThemeProvider';
import { QueryProvider } from '@/providers/QueryProvider';

export default function RootLayout() {
  return (
    <QueryProvider>
      <ThemeProvider>
        <Stack screenOptions={{ headerShown: false }}>
          <Stack.Screen name="(tabs)" />
          <Stack.Screen name="(auth)" />
          <Stack.Screen name="modal" options={{ presentation: 'modal' }} />
        </Stack>
      </ThemeProvider>
    </QueryProvider>
  );
}

Patterns

Pattern 1: Expo Router Navigation

// app/(tabs)/_layout.tsx
import { Tabs } from 'expo-router';
import { Home, Search, User, Settings } from 'lucide-react-native';
import { useTheme } from '@/hooks/useTheme';

export default function TabLayout() {
  const { colors } = useTheme();

  return (
    <Tabs
      screenOptions={{
        tabBarActiveTintColor: colors.primary,
        tabBarInactiveTintColor: colors.textMuted,
        tabBarStyle: { backgroundColor: colors.background },
        headerShown: false,
      }}
    >
      <Tabs.Screen
        name="index"
        options={{
          title: 'Home',
          tabBarIcon: ({ color, size }) => <Home size={size} color={color} />,
        }}
      />
      <Tabs.Screen
        name="search"
        options={{
          title: 'Search',
          tabBarIcon: ({ color, size }) => <Search size={size} color={color} />,
        }}
      />
      <Tabs.Screen
        name="profile"
        options={{
          title: 'Profile',
          tabBarIcon: ({ color, size }) => <User size={size} color={color} />,
        }}
      />
      <Tabs.Screen
        name="settings"
        options={{
          title: 'Settings',
          tabBarIcon: ({ color, size }) => <Settings size={size} color={color} />,
        }}
      />
    </Tabs>
  );
}

// app/(tabs)/profile/[id].tsx - Dynamic route
import { useLocalSearchParams } from 'expo-router';

export default function ProfileScreen() {
  const { id } = useLocalSearchParams<{ id: string }>();

  return <UserProfile userId={id} />;
}

// Navigation from anywhere
import { router } from 'expo-router';

// Programmatic navigation
router.push('/profile/123');
router.replace('/login');
router.back();

// With params
router.push({
  pathname: '/product/[id]',
  params: { id: '123', referrer: 'home' },
});

Pattern 2: Authentication Flow

// providers/AuthProvider.tsx
import { createContext, useContext, useEffect, useState } from 'react';
import { useRouter, useSegments } from 'expo-router';
import * as SecureStore from 'expo-secure-store';

interface AuthContextType {
  user: User | null;
  isLoading: boolean;
  signIn: (credentials: Credentials) => Promise<void>;
  signOut: () => Promise<void>;
}

const AuthContext = createContext<AuthContextType | null>(null);

export function AuthProvider({ children }: { children: React.ReactNode }) {
  const [user, setUser] = useState<User | null>(null);
  const [isLoading, setIsLoading] = useState(true);
  const segments = useSegments();
  const router = useRouter();

  // Check authentication on mount
  useEffect(() => {
    checkAuth();
  }, []);

  // Protect routes
  useEffect(() => {
    if (isLoading) return;

    const inAuthGroup = segments[0] === '(auth)';

    if (!user && !inAuthGroup) {
      router.replace('/login');
    } else if (user && inAuthGroup) {
      router.replace('/(tabs)');
    }
  }, [user, segments, isLoading]);

  async function checkAuth() {
    try {
      const token = await SecureStore.getItemAsync('authToken');
      if (token) {
        const userData = await api.getUser(token);
        setUser(userData);
      }
    } catch (error) {
      await SecureStore.deleteItemAsync('authToken');
    } finally {
      setIsLoading(false);
    }
  }

  async function signIn(credentials: Credentials) {
    const { token, user } = await api.login(credentials);
    await SecureStore.setItemAsync('authToken', token);
    setUser(user);
  }

  async function signOut() {
    await SecureStore.deleteItemAsync('authToken');
    setUser(null);
  }

  if (isLoading) {
    return <SplashScreen />;
  }

  return <AuthContext.Provider value={{ user, isLoading, signIn, signOut }}>{children}</AuthContext.Provider>;
}

export const useAuth = () => {
  const context = useContext(AuthContext);
  if (!context) throw new Error('useAuth must be used within AuthProvider');
  return context;
};

Pattern 3: Offline-First with React Query

// providers/QueryProvider.tsx
import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
import { createAsyncStoragePersister } from '@tanstack/query-async-storage-persister';
import { PersistQueryClientProvider } from '@tanstack/react-query-persist-client';
import AsyncStorage from '@react-native-async-storage/async-storage';
import NetInfo from '@react-native-community/netinfo';
import { onlineManager } from '@tanstack/react-query';

// Sync online status
onlineManager.setEventListener((setOnline) => {
  return NetInfo.addEventListener((state) => {
    setOnline(!!state.isConnected);
  });
});

const queryClient = new QueryClient({
  defaultOptions: {
    queries: {
      gcTime: 1000 * 60 * 60 * 24, // 24 hours
      staleTime: 1000 * 60 * 5, // 5 minutes
      retry: 2,
      networkMode: 'offlineFirst',
    },
    mutations: {
      networkMode: 'offlineFirst',
    },
  },
});

const asyncStoragePersister = createAsyncStoragePersister({
  storage: AsyncStorage,
  key: 'REACT_QUERY_OFFLINE_CACHE',
});

export function QueryProvider({ children }: { children: React.ReactNode }) {
  return (
    <PersistQueryClientProvider client={queryClient} persistOptions={{ persister: asyncStoragePersister }}>
      {children}
    </PersistQueryClientProvider>
  );
}

// hooks/useProducts.ts
import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';

export function useProducts() {
  return useQuery({
    queryKey: ['products'],
    queryFn: api.getProducts,
    // Use stale data while revalidating
    placeholderData: (previousData) => previousData,
  });
}

export function useCreateProduct() {
  const queryClient = useQueryClient();

  return useMutation({
    mutationFn: api.createProduct,
    // Optimistic update
    onMutate: async (newProduct) => {
      await queryClient.cancelQueries({ queryKey: ['products'] });
      const previous = queryClient.getQueryData(['products']);

      queryClient.setQueryData(['products'], (old: Product[]) => [...old, { ...newProduct, id: 'temp-' + Date.now() }]);

      return { previous };
    },
    onError: (err, newProduct, context) => {
      queryClient.setQueryData(['products'], context?.previous);
    },
    onSettled: () => {
      queryClient.invalidateQueries({ queryKey: ['products'] });
    },
  });
}

Pattern 4: Native Module Integration

// services/haptics.ts
import * as Haptics from 'expo-haptics';
import { Platform } from 'react-native';

export const haptics = {
  light: () => {
    if (Platform.OS !== 'web') {
      Haptics.impactAsync(Haptics.ImpactFeedbackStyle.Light);
    }
  },
  medium: () => {
    if (Platform.OS !== 'web') {
      Haptics.impactAsync(Haptics.ImpactFeedbackStyle.Medium);
    }
  },
  heavy: () => {
    if (Platform.OS !== 'web') {
      Haptics.impactAsync(Haptics.ImpactFeedbackStyle.Heavy);
    }
  },
  success: () => {
    if (Platform.OS !== 'web') {
      Haptics.notificationAsync(Haptics.NotificationFeedbackType.Success);
    }
  },
  error: () => {
    if (Platform.OS !== 'web') {
      Haptics.notificationAsync(Haptics.NotificationFeedbackType.Error);
    }
  },
};

// services/biometrics.ts
import * as LocalAuthentication from 'expo-local-authentication';

export async function authenticateWithBiometrics(): Promise<boolean> {
  const hasHardware = await LocalAuthentication.hasHardwareAsync();
  if (!hasHardware) return false;

  const isEnrolled = await LocalAuthentication.isEnrolledAsync();
  if (!isEnrolled) return false;

  const result = await LocalAuthentication.authenticateAsync({
    promptMessage: 'Authenticate to continue',
    fallbackLabel: 'Use passcode',
    disableDeviceFallback: false,
  });

  return result.success;
}

// services/notifications.ts
import * as Notifications from 'expo-notifications';
import { Platform } from 'react-native';
import Constants from 'expo-constants';

Notifications.setNotificationHandler({
  handleNotification: async () => ({
    shouldShowAlert: true,
    shouldPlaySound: true,
    shouldSetBadge: true,
  }),
});

export async function registerForPushNotifications() {
  let token: string | undefined;

  if (Platform.OS === 'android') {
    await Notifications.setNotificationChannelAsync('default', {
      name: 'default',
      importance: Notifications.AndroidImportance.MAX,
      vibrationPattern: [0, 250, 250, 250],
    });
  }

  const { status: existingStatus } = await Notifications.getPermissionsAsync();
  let finalStatus = existingStatus;

  if (existingStatus !== 'granted') {
    const { status } = await Notifications.requestPermissionsAsync();
    finalStatus = status;
  }

  if (finalStatus !== 'granted') {
    return null;
  }

  const projectId = Constants.expoConfig?.extra?.eas?.projectId;
  token = (await Notifications.getExpoPushTokenAsync({ projectId })).data;

  return token;
}

Pattern 5: Platform-Specific Code

// components/ui/Button.tsx
import { Platform, Pressable, StyleSheet, Text, ViewStyle } from 'react-native';
import * as Haptics from 'expo-haptics';
import Animated, { useAnimatedStyle, useSharedValue, withSpring } from 'react-native-reanimated';

const AnimatedPressable = Animated.createAnimatedComponent(Pressable);

interface ButtonProps {
  title: string;
  onPress: () => void;
  variant?: 'primary' | 'secondary' | 'outline';
  disabled?: boolean;
}

export function Button({ title, onPress, variant = 'primary', disabled = false }: ButtonProps) {
  const scale = useSharedValue(1);

  const animatedStyle = useAnimatedStyle(() => ({
    transform: [{ scale: scale.value }],
  }));

  const handlePressIn = () => {
    scale.value = withSpring(0.95);
    if (Platform.OS !== 'web') {
      Haptics.impactAsync(Haptics.ImpactFeedbackStyle.Light);
    }
  };

  const handlePressOut = () => {
    scale.value = withSpring(1);
  };

  return (
    <AnimatedPressable
     
     
     
      disabled={disabled}
      style={[styles.button, styles[variant], disabled && styles.disabled, animatedStyle]}
    >
      <Text style={[styles.text, styles[`${variant}Text`]]}>{title}</Text>
    </AnimatedPressable>
  );
}

// Platform-specific files
// Button.ios.tsx - iOS-specific implementation
// Button.android.tsx - Android-specific implementation
// Button.web.tsx - Web-specific implementation

// Or use Platform.select
const styles = StyleSheet.create({
  button: {
    paddingVertical: 12,
    paddingHorizontal: 24,
    borderRadius: 8,
    alignItems: 'center',
    ...Platform.select({
      ios: {
        shadowColor: '#000',
        shadowOffset: { width: 0, height: 2 },
        shadowOpacity: 0.1,
        shadowRadius: 4,
      },
      android: {
        elevation: 4,
      },
    }),
  },
  primary: {
    backgroundColor: '#007AFF',
  },
  secondary: {
    backgroundColor: '#5856D6',
  },
  outline: {
    backgroundColor: 'transparent',
    borderWidth: 1,
    borderColor: '#007AFF',
  },
  disabled: {
    opacity: 0.5,
  },
  text: {
    fontSize: 16,
    fontWeight: '600',
  },
  primaryText: {
    color: '#FFFFFF',
  },
  secondaryText: {
    color: '#FFFFFF',
  },
  outlineText: {
    color: '#007AFF',
  },
});

Pattern 6: Performance Optimization

// components/ProductList.tsx
import { FlashList } from '@shopify/flash-list';
import { memo, useCallback } from 'react';

interface ProductListProps {
  products: Product[];
  onProductPress: (id: string) => void;
}

// Memoize list item
const ProductItem = memo(function ProductItem({ item, onPress }: { item: Product; onPress: (id: string) => void }) {
  const handlePress = useCallback(() => onPress(item.id), [item.id, onPress]);

  return (
    <Pressable style={styles.item}>
      <FastImage source={{ uri: item.image }} style={styles.image} resizeMode="cover" />
      <Text style={styles.title}>{item.name}</Text>
      <Text style={styles.price}>${item.price}</Text>
    </Pressable>
  );
});

export function ProductList({ products, onProductPress }: ProductListProps) {
  const renderItem = useCallback(
    ({ item }: { item: Product }) => <ProductItem item={item} />,
    [onProductPress]
  );

  const keyExtractor = useCallback((item: Product) => item.id, []);

  return (
    <FlashList
      data={products}
      renderItem={renderItem}
      keyExtractor={keyExtractor}
      estimatedItemSize={100}
      // Performance optimizations
      removeClippedSubviews={true}
      maxToRenderPerBatch={10}
      windowSize={5}
      // Pull to refresh
     
      refreshing={isRefreshing}
    />
  );
}

EAS Build & Submit

// eas.json
{
  "cli": { "version": ">= 5.0.0" },
  "build": {
    "development": {
      "developmentClient": true,
      "distribution": "internal",
      "ios": { "simulator": true }
    },
    "preview": {
      "distribution": "internal",
      "android": { "buildType": "apk" }
    },
    "production": {
      "autoIncrement": true
    }
  },
  "submit": {
    "production": {
      "ios": { "appleId": "your@email.com", "ascAppId": "123456789" },
      "android": { "serviceAccountKeyPath": "./google-services.json" }
    }
  }
}

# Build commands
eas build --platform ios --profile development
eas build --platform android --profile preview
eas build --platform all --profile production

# Submit to stores
eas submit --platform ios
eas submit --platform android

# OTA updates
eas update --branch production --message "Bug fixes"

Best Practices

Do's

• Use Expo - Faster development, OTA updates, managed native code
• FlashList over FlatList - Better performance for long lists
• Memoize components - Prevent unnecessary re-renders
• Use Reanimated - 60fps animations on native thread
• Test on real devices - Simulators miss real-world issues

Don'ts

• Don't inline styles - Use StyleSheet.create for performance
• Don't fetch in render - Use useEffect or React Query
• Don't ignore platform differences - Test on both iOS and Android
• Don't store secrets in code - Use environment variables
• Don't skip error boundaries - Mobile crashes are unforgiving

Resources

• Expo Documentation
• Expo Router
• React Native Performance
• FlashList