Micro Frontend Demo

A project for demoing a micro frontend architecture in React with dynamic remote modules.

Check out the live version: https://micro-frontend-demo-main.vercel.app/

Getting started

Run: yarn start
Navigate to http://localhost:9001/

Main Host App: http://localhost:9001/ Products Remote: http://localhost:9002/ Cart Remote: http://localhost:9003/

Demo

Once you have the local app running go to the live instance https://micro-frontend-demo-main.vercel.app/ and change the URLs for the Products or Cart remote to the localhost version. Make some code changes and watch as the production version of main reflects your local changes!

Of course, this is only visible to you but this pattern opens the door for a lot of interesting and helpful developer experiences.

Dynamic Remotes

We are taking advantage of Webpack Module Federation's Dynamic Remote Containers to dynamically update the remote apps within a React micro frontend.

This works by injecting a script tag into the DOM to fetch the remote app at run time using the fetchRemote function found in: main/src/utils/index.js

RemoteComponent is a React component we can re-use throughout our application to render modules from a remote app. It encapsulates:

ErrorBoundary to safely render remote code without breaking our host app. Lazy loading using React.Lazy to fetch and resolve the remote code as needed without blocking the rest of our app rendering. Fetching and managing remote containers.

<RemoteComponent
  // Text displayed while the component is being fetched
  fallback="Loading..."
  // Which remote to fetch the component from
  remote="RemoteApp"
  // Name of the React component exposed in our remote app
  module="HelloWorld"
/>

The implementation can be found in: main/src/components/RemoteComponent/index.tsx

Within the implementation we call a loadComponent function that acts as a middle man between the RemoteComponent and fetchRemote functions to manage our loaded remote containers.

Tech Stack

Turborepo
React
Typescript
Webpack v5 (w/ Module Federation)

Iterations

Dynamic remote containers: https://github.com/rautio/micro-frontend-demo/tree/dynamic-remote-react
Zustand global state: https://github.com/rautio/micro-frontend-demo/tree/zustand-remote-state
Deploy using environment variables: https://github.com/rautio/micro-frontend-demo/tree/env-variable-deploy

Related Blog Posts

How to use Webpack Module Federation in React: https://betterprogramming.pub/how-to-use-webpack-module-federation-in-react-70455086b2b0
Zustand in a Micro Frontend: https://betterprogramming.pub/zustand-in-a-micro-frontend-b92d02a51577

Rendering Remote React Components

To safely load react components you need an ErrorBoundary and should wrap the fetch logic within lazy loading and optionally use React.Suspense to render a friendly loading message.

const RemoteComponent = React.lazy(() => import("Remote/Component"));

export const App = () => (
  <ErrorBoundary>
    <React.Suspense fallback="Loading...">
      <RemoteComponent />
    </React.Suspense>
  </ErrorBoundary>
)

rautio / micro-frontend-demo