Micro Frontend Demo

A sample repo for demoing a micro frontend architecture setup.

Getting started

1. Run: yarn start
2. Navigate to http://localhost:9001/

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

Architecture

TBD

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

Open Items

• Dynamic remote URLs
• Deployment
• Sharing state from host to application (props)
• Sharing global state from host to remotes (zustand?)
• Sharing local storage (persist cart)
• Central analytics event stream
• Error Boundary/Safe loading. + Suspense in 'FederatedWrapper'
• Versioning between host and remotes
• Versioning node_modules?
• Routing. How do you do in-browser linking from a remote component when the host is the one controlling the router? What happens if you use mismatching versions of react-router?
• How can you share local/session state between remote and host?

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>
)