Vite plugin for Module Federation

Reason why 🤔

Microservices nowadays is a well-known concept and maybe you are using it in your current company. Do you know that now you can apply similar ideas on the Frontend? With Module Federation you can load separately compiled and deployed code into a unique application. This plugin makes Module Federation work together with Vite.

Working implementations

Vue

React

Svelte

SvelteKit

SolidJS

More examples here

Try this crazy example with all these bundlers together

pnpm install
pnpm run build
pnpm run multi-example

Getting started 🚀

https://module-federation.io/guide/basic/webpack.html

With @module-federation/vite, the process becomes delightfully simple, you will only find the differences from a normal Vite configuration.

This example is with Vue.js
The @module-federation/vite configuration remains the same for different frameworks.

The Remote Application configuration

file: remote/vite.config.ts

import { defineConfig } from 'vite';
import { federation } from '@module-federation/vite'; 👈

export default defineConfig({
  [...]
  plugins: [
    [...]
    federation({ 👈
      name: "remote",
      filename: "remoteEntry.js",
      // optional: additional "var" remoteEntry file
      // needed only for legacy hosts with "var" usage (remote.type = 'var')
      varFilename: "varRemoteEntry.js",
      exposes: {
        "./remote-app": "./src/App.vue",
      },
      shared: ["vue"],
    }),
  ],
  server: {
    origin: "http://localhost:{Your port}"
  },
  // Do you need to support build targets lower than chrome89?
  // You can use 'vite-plugin-top-level-await' plugin for that.
  build: {
    target: 'chrome89',
  },
  [...]
});

In this remote app configuration, we define a remoteEntry.js file that will expose the App component. The shared property ensures that both host and remote applications use the same vue library.

The Host Application configuration

file host/vite.config.ts

import { defineConfig } from 'vite';
import { federation } from '@module-federation/vite'; 👈

export default defineConfig({
  [...]
  plugins: [
    [...]
    federation({ 👈
      name: "host",
      remotes: {
        remote: {
          type: "module", // type "var" (default) for vite remote is supported with remote's `varFilename` option
          name: "remote",
          entry: "https://[...]/remoteEntry.js",
          entryGlobalName: "remote",
          shareScope: "default",
        },
      },
      filename: "remoteEntry.js",
      shared: ["vue"],
      // Optional parameter that controls where the host initialization script is injected.
      // By default, it is injected into the index.html file.
      // You can set this to "entry" to inject it into the entry script instead.
      // Useful if your application does not load from index.html.
      hostInitInjectLocation: "html", // or "entry"
      // Controls whether all CSS assets from the bundle should be added to every exposed module.
      // When false (default), the plugin will not process any CSS assets.
      // When true, all CSS assets are bundled into every exposed module.
      bundleAllCSS: false, // or true
      // Timeout for parsing modules in seconds.
      // Defaults to 10 seconds.
      moduleParseTimeout: 10,
      // Idle timeout for parsing modules in seconds. When set, the timeout
      // resets on every parsed module and only fires when there has been no
      // module activity for the configured duration. Prefer this over
      // moduleParseTimeout for large codebases where total build time may
      // exceed the fixed timeout value.
      moduleParseIdleTimeout: 10,
    }),
  ],
  server: {
    origin: "http://localhost:{Your port}"
  },
  // Do you need to support build targets lower than chrome89?
  // You can use 'vite-plugin-top-level-await' plugin for that.
  build: {
    target: 'chrome89',
  },
  [...]
});

The host app configuration specifies its name, the filename of its exposed remote entry remoteEntry.js, and importantly, the configuration of the remote application to load. You can specify the place the host initialization file is injected with the hostInitInjectLocation option, which is described in the example code above. The moduleParseTimeout option allows you to configure the maximum time to wait for module parsing during the build process. The moduleParseIdleTimeout option is an alternative that resets the timer on every parsed module. It only fires when there has been no module activity for the configured duration, making it suitable for large codebases where the total build time exceeds the fixed timeout.

Load the Remote App

In your host app, you can now import and use the remote app with defineAsyncComponent

file host/src/App.vue

<script setup lang="ts">
import { defineAsyncComponent } from "vue";
const RemoteMFE = defineAsyncComponent( 👈
  () => import("remote/remote-app")
);
</script>

<template>
  <RemoteMFE v-if="!!RemoteMFE" /> 👈
</template>

So far so good 🎉

Now you are ready to use Module Federation in Vite!