From Web to Mobile: Converting a React.js App into a React Native App

With the growing demand for mobile apps, many developers find themselves wanting to bring their web applications to mobile platforms. If you've built a web app using React.js, you're already familiar with much of the ecosystem, making React Native an excellent choice for creating mobile apps. This blog will guide you through the process of converting a React.js app into a React Native app, offering tips and tools for a smooth transition.

---

Why React Native?

React Native allows you to build cross-platform mobile apps using JavaScript and React. It provides a near-native experience by leveraging platform-specific components while maintaining a single codebase for iOS and Android.

If you're already comfortable with React.js, transitioning to React Native can feel natural since both share similar concepts like components, state, and props.

---

Key Differences Between React.js and React Native

Before jumping into conversion, it's important to understand the differences:

1. HTML & CSS: React.js uses HTML and CSS for UI, but React Native uses its own components (e.g., <View>, <Text>, <Image>), styled via JavaScript objects.

2. DOM vs Native APIs: React.js manipulates the DOM, whereas React Native interacts with native mobile APIs.

3. Routing: React Router is commonly used in web apps, while React Native uses libraries like React Navigation.

4. Styling: Instead of CSS files, React Native uses StyleSheet or libraries like Tailwind CSS (via tailwind-rn) for styling.

---

Steps to Convert a React.js App into a React Native App

1. Set Up Your React Native Environment

Start by setting up a React Native environment:

• Install Node.js and npm.

• Install Expo CLI or React Native CLI for creating a new project.

# Using Expo
npx expo-cli init MyReactNativeApp

# Using React Native CLI
npx react-native init MyReactNativeApp

---

2. Identify Reusable Components

Examine your React.js app for components that can be reused in the mobile version:

• Logic and State Management: Hooks like useState and useEffect can be reused.

• Reusable Functions: Any helper functions, utilities, or business logic can be copied directly.

---

3. Replace Web-Specific Components

Since React Native does not support HTML tags like <div> or <button>, replace them with their React Native counterparts:

• <div> → <View>

• <p> or <span> → <Text>

• <img> → <Image>

Example:

// React.js
<div className="container">
  <h1>Hello, World!</h1>
  <img src="logo.png" alt="Logo" />
</div>

// React Native
import { View, Text, Image } from 'react-native';

<View style={{ padding: 10 }}>
  <Text style={{ fontSize: 20 }}>Hello, World!</Text>
  <Image source={require('./logo.png')} style={{ width: 100, height: 100 }} />
</View>

---

4. Adapt Styling

React Native styling uses JavaScript objects instead of CSS. Transition your styles as follows:

• Inline styles or create styles using StyleSheet.

• If you're using a CSS framework like Tailwind CSS, consider libraries like tailwind-rn.

Example:

// React.js (CSS)
<div className="container">Hello</div>

// React Native (StyleSheet)
import { StyleSheet, View, Text } from 'react-native';

<View style={styles.container}>
  <Text>Hello</Text>
</View>;

const styles = StyleSheet.create({
  container: {
    padding: 10,
    backgroundColor: 'lightblue',
  },
});

---

5. Implement Navigation

React Native doesn't support React Router. Use React Navigation instead:

npm install @react-navigation/native
npm install react-native-screens react-native-safe-area-context react-native-gesture-handler react-native-reanimated react-navigation-stack

Configure navigation:

import { NavigationContainer } from '@react-navigation/native';
import { createStackNavigator } from '@react-navigation/stack';

const Stack = createStackNavigator();

function App() {
  return (
    <NavigationContainer>
      <Stack.Navigator>
        <Stack.Screen name="Home" component={HomeScreen} />
        <Stack.Screen name="Details" component={DetailsScreen} />
      </Stack.Navigator>
    </NavigationContainer>
  );
}

---

6. Handle Platform-Specific Features

Leverage React Native's ability to target iOS and Android differently using:

• Platform-specific files (MyComponent.ios.js, MyComponent.android.js).

• The Platform API to apply conditional logic.

Example:

import { Platform } from 'react-native';

const platformMessage = Platform.OS === 'ios' ? 'Welcome iOS User!' : 'Welcome Android User!';

---

7. Test Your App

Test thoroughly on both iOS and Android simulators or devices. Use Expo for easier testing.

---

Tools to Simplify Conversion

• Expo: Simplifies app development with pre-configured settings.

• React Native Elements: Provides a set of customizable UI components.

• Tailwind-rn: Adapts Tailwind CSS for React Native.

---

Tips for a Smooth Transition

1. Keep the UI Simple: Mobile screens are smaller; adapt layouts accordingly.

2. Optimize Performance: Lazy load components, optimize images, and reduce unnecessary re-renders.

3. Focus on Accessibility: Use accessibility properties like accessible and accessibilityLabel.

---

Conclusion

Converting a React.js app to React Native is a manageable process, especially if you understand the differences and take advantage of reusable logic and components. By following the steps above, you can efficiently bring your web app to mobile platforms and reach a broader audience.

Happy coding! 🎉