First Federated Application

First Federated Application Overview

First Federated Application lets you structure Module Federation work so it stays readable, testable, and easy to scale. Instead of ad-hoc code, you follow a clear pattern that other developers can recognise immediately.

The key is to keep first federated application focused and predictable. Start from the minimal example here, then layer in only the complexity your feature actually needs.

const { ModuleFederationPlugin } = require('webpack').container;

module.exports = {
  plugins: [
    new ModuleFederationPlugin({
      name: 'shell',
      remotes: { catalog: 'catalog@http://localhost:3001/remoteEntry.js' },
      exposes: {},
      shared: { react: { singleton: true }, 'react-dom': { singleton: true } },
    }),
  ],
};

ModuleFederationPlugin configures which modules an app exposes, consumes, and shares.

First Federated Application Example

new ModuleFederationPlugin({
  name: 'app',
  filename: 'remoteEntry.js',
  exposes: { './Widget': './src/Widget' },
  remotes: { other: 'other@http://host/remoteEntry.js' },
  shared: { react: { singleton: true } },
});

• Start from a minimal First Federated Application example and grow it only as needed.
• Keep configuration explicit so First Federated Application behaves the same in every environment.
• Name things clearly so teammates understand your First Federated Application at a glance.
• Add tests around First Federated Application early to lock in expected behaviour.

Module Federation Cheatsheet

Key Module Federation settings related to first federated application.

How First Federated Application Works in Module Federation

First Federated Application builds on Module Federation's ability to load code from another independently built and deployed application at runtime. Each app can be a host, a remote, or both.

ModuleFederationPlugin configures which modules an app exposes, consumes, and shares.

• Remotes expose modules through a remoteEntry.js manifest.
• Hosts declare remotes and import exposed modules dynamically.
• Shared dependencies are deduplicated, ideally as singletons.
• Each micro frontend builds and deploys on its own schedule.

Practical Guidance for First Federated Application

In production, first federated application needs careful version management and graceful failure handling. Align shared dependency versions and always render a fallback when a remote cannot load.

Common Mistakes

• Skipping error handling and edge cases when wiring up first federated application.
• Leaving first federated application untested, so regressions slip into production.
• Over-engineering first federated application before you actually need the extra flexibility.
• Ignoring documentation, which makes first federated application hard for the next developer to change.

Key Takeaways

• First Federated Application is a core part of working effectively with Module Federation.
• Start small and keep first federated application focused on a single responsibility.
• Apply consistent patterns so first federated application scales across your project.
• Test and document first federated application to keep it maintainable over time.