Micro-frontend, Module Federation

Learn how to build a scalable super app with React Native and Module Federation. This guide covers micro frontends, modular architecture, and seamless integration techniques for modern app development

Building a Super App with React Native and Module Federation: A Step-by-Step Guide

Building a super app with micro frontends in React Native using Module Federation involves a combination of tools, strategies, and patterns. Module Federation, introduced in Webpack 5, enables sharing code between different applications (or micro frontends). In the context of React Native, you can achieve a similar architecture by combining Module Federation concepts with React Native-specific tools and strategies. Here's a step-by-step guide:

1. Understand the Requirements

• Super App: A unified app hosting multiple smaller apps (micro-apps) with their own independent development, deployment, and scaling.

• Micro Frontends: Breaking down your super app into smaller, self-contained modules that are independently deployable and maintainable.

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2. Tools and Libraries

• Webpack 5 with Module Federation: Use for code splitting and sharing components across micro-apps.

• React Native Web: Bridges React Native components to the web, making them compatible with Module Federation.

• Metro Bundler: The React Native default bundler. You'll need to adjust its setup for federation.

• Hermes or JSI: Use JavaScript engines and bridging for efficient communication between modules.

• React Navigation: For seamless navigation between micro frontends.

• Module Federation Tools: Libraries like @module-federation/native-federation.

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3. Architecture

1. Super App Shell:

   • Acts as a host container for micro frontends.

   • Manages shared services like authentication, global state, theming, and navigation.

   • Loads micro frontends dynamically using Module Federation.

2. Micro Frontends:

   • Self-contained React Native applications or features.

   • Expose components, screens, or services via Module Federation.

3. Shared Components and Libraries:

   • Reusable UI components, hooks, or utilities shared across micro frontends.

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4. Implement Module Federation

1. Setup Webpack for Module Federation:

   • Configure Webpack in each micro frontend and the super app to expose/consume modules.

   Example webpack.config.js for a micro-frontend:

   javascriptCopy codeconst { ModuleFederationPlugin } = require('webpack').container;
   
   module.exports = {
     // Other configurations
     plugins: [
       new ModuleFederationPlugin({
         name: 'MicroFrontend',
         filename: 'remoteEntry.js',
         exposes: {
           './SomeComponent': './src/components/SomeComponent',
         },
         shared: ['react', 'react-native'],
       }),
     ],
   };

   In the super app:

   javascriptCopy codeconst { ModuleFederationPlugin } = require('webpack').container;
   
   module.exports = {
     plugins: [
       new ModuleFederationPlugin({
         name: 'SuperApp',
         remotes: {
           MicroFrontend: 'MicroFrontend@http://localhost:3001/remoteEntry.js',
         },
         shared: ['react', 'react-native'],
       }),
     ],
   };

2. React Native Web for Compatibility:

   • Add react-native-web to your micro frontends to make them compatible with Webpack.

   • Configure aliases in webpack.config.js for React Native dependencies.

   javascriptCopy coderesolve: {
     alias: {
       'react-native$': 'react-native-web',
     },
   },

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5. Metro Bundler Configuration

To use Module Federation with React Native’s Metro bundler:

• Consider using tools like @module-federation/native-federation to adapt Module Federation concepts to React Native.

• Update metro.config.js to work with federated modules.

Example:

javascriptCopy codeconst { withMetro } = require('@module-federation/native-federation/metro');

module.exports = withMetro({
  projectRoot: __dirname,
});

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6. Navigation Integration

• Use React Navigation to allow seamless navigation between micro frontends.

• Each micro frontend defines its own navigation stack but integrates with the super app shell.

Example:

javascriptCopy codeconst AppShell = () => {
  return (
    <NavigationContainer>
      <Stack.Navigator>
        <Stack.Screen name="Home" component={HomeScreen} />
        <Stack.Screen
          name="MicroFrontend"
          getComponent={() => import('MicroFrontend/SomeScreen').then((mod) => mod.default)}
        />
      </Stack.Navigator>
    </NavigationContainer>
  );
};

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7. Shared State Management

Use libraries like Redux or Recoil for shared global state across micro frontends. Use Webpack’s shared configuration to ensure dependencies are not duplicated.

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8. Deployment and Updates

• Host micro frontends independently (e.g., on a CDN or a server).

• Use Module Federation to load the latest version dynamically, enabling incremental updates without redeploying the super app.

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9. Testing and Performance Optimization

• Test each micro frontend independently.

• Optimize Webpack configurations for tree-shaking and efficient code splitting.

• Use tools like React DevTools and Profiler for debugging.

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10. Challenges to Address

• Performance: Ensure seamless user experience with lazy loading and efficient communication.

• Consistency: Maintain UI and state consistency across micro frontends.

• Compatibility: Resolve issues between Metro and Webpack.

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Example Repository

• Consider starting with this guide on Module Federation with React Native or a boilerplate that supports React Native and Webpack integration.