Simplifying Angular Development with the Facade Pattern

Angular, as a robust framework, provides developers with the tools to build complex and feature-rich applications. However, as applications grow, managing different parts of the system can become challenging. This is where design patterns, such as the Facade Pattern, come into play.

Angular, as a robust framework, provides developers with the tools to build complex and feature-rich applications. However, as applications grow, managing different parts of the system can become challenging. This is where design patterns, such as the Facade Pattern, come into play.

Understanding the Facade Pattern

The Facade Pattern is a structural design pattern that provides a simplified interface to a set of interfaces in a subsystem. It acts as a unified interface to a set of interfaces in a subsystem, making it easier to use and understand. This pattern promotes loose coupling between clients and the subsystem, allowing for more maintainable and scalable code.

When to Use the Facade Pattern

Consider using the Facade Pattern when:

1. There's a complex subsystem: When your Angular application has a complex system of services or components, the Facade Pattern can help simplify the interaction with this subsystem.
2. Clients need a simplified interface: If certain parts of your application need a simpler interface and don't need to be concerned with the details of the subsystem, a facade can provide a clean and easy-to-use API.

Example: Facade Pattern in Angular

The source can be downloaded from GitHub.

Let's consider a scenario where we have multiple services (ServiceAService and ServiceBService) representing a subsystem, and we want to create a simplified interface to interact with them.

Step 1. Create the Subsystem Services

// service-a.service.ts
import { Injectable } from '@angular/core';

@Injectable({
  providedIn: 'root'
})
export class ServiceAService {

  constructor() { }

  methodA(): string {
    return 'Method A';
  }
}

// service-b.service.ts
import { Injectable } from '@angular/core';

@Injectable({
  providedIn: 'root'
})
export class ServiceBService {

  constructor() { }

  methodB(): string {
    return 'Method B';
  }
}

Step 2. Create the Facade Service

import { Injectable } from '@angular/core';
import { ServiceAService } from './service-a.service';
import { ServiceBService } from './service-b.service';

@Injectable({
  providedIn: 'root'
})
export class FacadeServiceService {

  constructor(
    private serviceA:ServiceAService,
    private serviceB:ServiceBService

  ) {   }

  simplifiedOperation(): string {
    const resultA = this.serviceA.methodA();
    const resultB = this.serviceB.methodB();
    return `${resultA} - ${resultB}`;
  }
}

Step 3. Use the Facade Service in a Component

//app.component.ts
import { Component } from '@angular/core';
import { FacadeServiceService } from './facade-service.service';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.sass']
})
export class AppComponent {
  title = 'angular-facade';
  operationResult:string | undefined;
  
  /**
   *
   */
  constructor(
    private facadeService:FacadeServiceService
  ) {
   
    this.operationResult = this.facadeService.simplifiedOperation();    
  }
  
}

Note: html file will be available in the source code. I would request you to take a look at it.

Step 4. Output

In this example, the FacadeService acts as a simplified interface to the subsystem, combining the results from ServiceAService and ServiceBService. The AppComponent then uses this facade to perform an operation without needing to know the details of the underlying services.

Conclusion

The Facade Pattern in Angular can significantly enhance the maintainability and readability of your code, especially as your application grows in complexity. By providing a simplified interface to a subsystem, you can encapsulate the details, making it easier for developers to work with specific functionalities without being burdened by the intricacies of the underlying system. Consider incorporating the Facade Pattern into your Angular applications to promote cleaner and more modular code.