@module-federation/vite/README.md

Vite plugin for Module Federation

# Vite plugin for Module Federation

[![npm](https://img.shields.io/npm/v/@module-federation/vite.svg)](https://www.npmjs.com/package/@module-federation/vite)

## Reason why 🤔

[Microservices](https://martinfowler.com/articles/microservices.html) 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](https://blog.logrocket.com/building-micro-frontends-webpacks-module-federation/#:~:text=Module%20federation%20is%20a%20JavaScript,between%20two%20different%20application%20codebases.) you can load separately compiled and deployed code into a unique application.
This plugin makes Module Federation work together with [Vite](https://vitejs.dev/).

## Working implementations

### [Vue](https://github.com/gioboa/vue-microfrontend-demo)

### [React](https://github.com/gioboa/react-microfrontend-demo)<br>

### [Svelte](https://github.com/gioboa/svelte-microfrontend-demo)<br>

### [SvelteKit](https://github.com/gioboa/sveltekit-microfrontend-demo)<br>

### [SolidJS](https://github.com/gioboa/solid-microfrontend-demo)<br>

### [More examples here](https://github.com/module-federation/vite/tree/main/examples)<br>

## Try this crazy example with all these bundlers together

<img src="./docs/multi-example.png"/>

<p float="left">
  <img src="./docs/vite.webp" width="150" />
  <img src="./docs/webpack.webp" width="160" /> 
  <img src="./docs/rspack.webp" width="200" />
</p>

```bash
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](https://vuejs.org/)</br>
> The @module-federation/vite configuration remains the same for different frameworks.

## The Remote Application configuration

file: **remote/vite.config.ts**

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

export default defineConfig({
  [...]
  plugins: [
    [...]
    federation({ 👈
      name: "remote",
      filename: "remoteEntry.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**

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

export default defineConfig({
  [...]
  plugins: [
    [...]
    federation({ 👈
      name: "host",
      remotes: {
        remote: {
          type: "module",
          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
    }),
  ],
  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.

## Load the Remote App

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

file **host/src/App.vue**

```ts
<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!