รู้จัก Module Federation

Welcome! In this lesson, we'll dive into Module Federation, a powerful feature of Webpack that's key to building modern Micro Frontends.

It allows different JavaScript applications to share and consume code from each other dynamically at runtime.

Traditionally, large web applications are built as a single, giant codebase – a monolith. This can lead to:

• Slow development cycles
• Difficulty scaling teams
• Tight coupling between parts

Module Federation helps overcome these challenges by enabling a more modular approach.

The core idea of Module Federation is dynamic code sharing. Instead of bundling all code together at build time, it lets applications load pieces of code from other applications at runtime.

Think of it like an app saying, "I need this component, and I know where to get it from another running app!"

In a Module Federation setup, we have two main types of applications:

• Remote Application: This app exposes its code (components, functions) for others to use.
• Host Application: This app consumes or uses the code exposed by a remote application.

An app can be both a host and a remote simultaneously!

A remote application uses Webpack's ModuleFederationPlugin to declare which parts of its code it wants to expose. These exposed modules become available for other applications to consume.

Here's a simplified example of how a remote app might expose a Button component:

A host application also uses the ModuleFederationPlugin to specify which remote applications it wants to consume modules from. It provides a URL where the remote's entry file (e.g., remoteEntry.js) can be found.

Here's how a host app might declare its intent to use remoteApp:

When a host application starts, it doesn't immediately load all remote code. Instead, it first loads a tiny file from the remote called remoteEntry.js.

This file acts as a manifest, telling the host what modules the remote exposes and how to dynamically load them if needed. Code is fetched only when requested!

One of the biggest advantages of Module Federation is enabling independent deployments.

Teams can develop, test, and deploy their micro frontends separately without coordinating a large, synchronized release for the entire application. This speeds up delivery and reduces risk.

Module Federation isn't just for sharing UI components. You can expose and consume various types of code:

• Utility functions
• Data services
• React hooks or similar logic
• Shared styles or themes

This allows for robust code reuse across your federated applications.

Module Federation introduces new ways for applications to interact. Which of the following statements correctly describe the core concepts?

Great job! You've grasped the fundamental idea of Module Federation.

• It's a Webpack feature for dynamic code sharing.
• Apps can be hosts (consuming) or remotes (exposing).
• It enables independent deployments and efficient code reuse.

Next, we'll look deeper into how host and remote applications are set up!