@module-federation/typescript

Federated Types

This plugin enables Typescript Types support for Module Federated Components.

Installation

$ npm i @module-federation/typescript

Usage

Register the plugin in webpack configuration (webpack.config.js) file

import webpack from 'webpack';
const { FederatedTypesPlugin } = require('@module-federation/typescript');

const federationConfig = {
  name: 'my-app',
  filename: 'remoteEntry.js',
  exposes: {
    //...exposed components
    './Button': './src/Button',
    './Input': './src/Input',
  },
  remotes: {
    app2: 'app2@http://localhost:3002/remoteEntry.js', // or Just the URL 'http://localhost:3002'
  },
  shared: ['react', 'react-dom'],
};

module.exports = {
  /* ... */
  plugins: [
    // ...
    new FederatedTypesPlugin({
      federationConfig,
      // ...
    }),
  ],
};

If you are running multiple remotes that use bi-directional module sharing, you may run into race conditions while starting up the webpack-dev-servers. The library now supports configuring retry options (which are enabled by default), along with the ability to serve the types out of the webpack compiler in a separate HTTP host.

Remember to only use typeServeOptions if you need to host them outside of webpack-dev-server locally, you'll also need to set the federationConfig for this plugin to reflect that new http server url.

module.exports = {
  /* ... */
  plugins: [
    // ...
    new FederatedTypesPlugin({
      federationConfig,
      typeFetchOptions: {
        /** The maximum time to wait for downloading remote types in milliseconds.
         * @default 2000  */
        downloadRemoteTypesTimeout?: number;
        /** The maximum number of retry attempts.
         * @default 3  */
        maxRetryAttempts?: number;
        /** The default number of milliseconds between retries.
         * @default 1000  */
        retryDelay?: number;
        /** Should retry if no types are found in destination. This could be due to another instance still compiling.
         * @default true  */
        shouldRetryOnTypesNotFound?: boolean;
        /** Should retry type fetching operations.
         * @default true  */
        shouldRetry?: boolean;
      },
      // Only enable if you need to serve types outside of webpack-dev-server
      typeServeOptions: {
        /** The port to serve type files on, this is separate from the webpack dev server port. */
        port?: number;
        /** The host to serve type files on. Example: 'localhost' */
        host?: string;
      }
      // ...
    }),
  ],
};

To enable verbose logging add folowing in webpack config:

infrastructureLogging: {
  level: 'log';
}

The Module Federation plugin is required to be registered separately from this plugin. The federation configuration provided to the Typescript plugin or Module Federation plugin can be different, as an example - to discern pure javascript remotes from Typescript remotes.

You need to register this plugin in both remote and host apps. The plugin will automatically create a directory named @mf-types in the host app - that contains all the types exported by the remote apps.

To have the type definitions automatically found for imports, add paths in tsconfig.json:

{
  "compilerOptions": {
    "baseUrl": ".",
    "paths": {
      "*": ["./@mf-types/*"]
    }
  }
}

baseUrl must also be set for paths to work properly

Plugin Options

Setting	Type	Required	Default	Description
additionalFilesToCompile	string[]	No	[]	Any additional files to be included (besides ModuleFederationPluginOptions.remotes) in the emission of Typescript types. This is useful for global.d.ts files not directly referenced.
compiler	tsc or vue-tsc	No	tsc	The compiler to use to emit declaration files. Use vue-tsc to emit declarations from your Vue Templates
disableTypeCompilation	boolean	No	false	Disable compiling types for exposed components
disableDownloadingRemoteTypes	boolean	No	false	Disable downloading types from remote apps
downloadRemoteTypesTimeout	number	No	2000	The maximum time to wait for downloading remote types. This is to prevent blocking compilation or hanging the plugin.
federationConfig		Yes	-	Configuration for ModuleFederationPlugin
typescriptFolderName	string	No	@mf-types	The folder name to download remote types and output compiled types
typescriptCompiledFolderName	string	No	_types	The folder name to output the raw output from the ts compiler

Usage in Next.js

You need to manually pass the federationConfig object to the plugin. The remotes value should contain absolute path.

Sample code:

// next.config.js
const FederatedTypesPlugin = require('@module-federation/typescript');

module.exports = {
  webpack: (config, { buildId, dev, isServer, defaultLoaders, webpack }) => {
    config.plugins.push(
      new FederatedTypesPlugin({
        federationConfig: {
          ...federationConfig,
          remotes: { app2: 'app2@http://localhost:3000/remoteEntry.js' },
        },
        // ...
      }),
    );
    return config;
  },
};

Support

Drop me a message on twitter for support/feedback, or maybe just say Hi at @prasannamestha

Credits

Shoutout to @ScriptedAlchemy for helping with the development of this plugin.