Micro Frontend Architecture in Angular

As web applications eventually become increasingly large and complicated, it becomes more and more difficult to manage scale, flexibility, and independent development. This is where Micro Frontend Architecture comes in—a design pattern that forms a monolithic frontend into smaller, component-modularized, and independently deployable components. Due to Angular’s modular architecture and tooling, it is a wonderful framework to implement Micro Front ends effectively.

What Is Micro Frontend Architecture?

Micro Frontend Architecture is the frontend extension of the concept of microservices. Rather than building a single large monolithic/ tightly coupled frontend application, you break down the frontend into smaller, feature-related modules (micro frontends). These micro frontends can be implemented, tested, and deployed by numerous teams, allowing you to improve development speed and ease of maintenance.
For instance, an e-commerce website could break its frontend into micro frontends such as:

• Product Catalog
• Shopping Cart
• User Account
• Checkout System

All of these micro frontends would be implemented and maintainable independently from one another, but they would relatively each communicate with one another through shared APIs or some shell application that links them together nicely.

Reasons for Selecting Micro Frontends with Angular?

Since Angular is modular by nature—using components, modules, and services enables components of the application to be separated and managed reasonably well. Using micro frontends with Angular also increases:

• Scaling: Teams can develop different micro frontends without colliding or blocking each other
• Speed: Teams can deliver features faster, with independent deployments and CI/CD pipelines
• Technology Agility: Teams can seek a refactor or even more current versions of Angular (or other frameworks) for specific micro frontends.
• Maintainability: Smaller codebases are easier to debug, refactor, or test.

Utilizing Micro Frontends in Angular

Module Federation with Webpack 5

One of the most popular approaches for implementing Angular micro frontends is through Webpack Module Federation. This allows code and dependencies to be shared dynamically between Angular applications at runtime.

• A Host App (Shell) loads Remote Apps (Micro Frontends).
• Each micro frontend exposes components, or modules, that can be consumed by the host app.

Shared State and Communication

Micro frontends need to share data with each other, for example – to share information about an ongoing shopping cart, user preferences, etc. Angular has a number of different ways to share information.

• RxJS Subjects for event streams.
• Shared Services for any state management.
• Custom Events, or even message buses, for loosely coupled event based communication.

Routing Across Micro Frontends

Each micro frontend may define its own routing config. The router for the shell app can integrate those micro frontends using lazy loaded modules, and will generally be seamless to the user.

Styling and Consistency

In order to keep a consistent look and feel, it is worth considering:

• A shared design system (Angular Material or a custom UI library).
• CSS encapsulation and/or scoped styles to avoid conflicts.

Deployment and Versioning

Micro frontends can be deployed independently of each other. This is beneficial for the ability to rollback and/or update as individual micro apps have their own lifecycle separate from the system as a whole. CI/CD pipelines for automating the integration and versioning are recommended.

Challenges and Recommended Practices

Challenges

• Managing common dependencies and their version conflicts.
• Maintaining a uniform UX among all the micro frontends.
• Managing multi-modular communication effectively.

Recommended Practices

• Utilize Module Federation for dependency management.
• Use a shared UI library for consistency.
• Limit micro frontends to a single business capability..
• Utilize CI/CD toolchain for automated testing and deployment.

Conclusion

Micro Frontend Architecture with Angular allows organizations to create scalable, maintainable, and agile web applications. By breaking large applications into multiple smaller applications, the development process is easier to innovate, less complicated, and more reliable overall. As a library, Angular provides an efficient and smooth implementation of micro frontends which signals a paradigm shift towards the next iteration of modular development for the Web.
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