Shared Design Tokens

Shared Design Tokens Overview

Shared Design Tokens is a building block you will reach for often in Module Federation. It keeps related logic together and makes your intent obvious to reviewers and future maintainers.

When you learn shared design tokens properly, you avoid the guesswork that leads to bugs and rework. The example below shows the shape you will use in most real Module Federation projects.

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.

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

Module Federation Cheatsheet

Key Module Federation settings related to shared design tokens.

How Shared Design Tokens Works in Module Federation

Shared Design Tokens 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 Shared Design Tokens

In production, shared design tokens 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 shared design tokens.
• Leaving shared design tokens untested, so regressions slip into production.
• Over-engineering shared design tokens before you actually need the extra flexibility.
• Ignoring documentation, which makes shared design tokens hard for the next developer to change.

Key Takeaways

• Shared Design Tokens is a core part of working effectively with Module Federation.
• Start small and keep shared design tokens focused on a single responsibility.
• Apply consistent patterns so shared design tokens scales across your project.
• Test and document shared design tokens to keep it maintainable over time.