What are Services in Angular

Introduction to Services

Angular services are singleton objects that are responsible for encapsulating and sharing business logic, data, or functionality across different parts of an application.

What is a Service:

• A service is a class in Angular that can be injected into components, providing a way to share common functionality.
• Services promote modularity and maintainability by separating concerns.

Dependency Injection in Angular

Angular uses a hierarchical dependency injection system to manage the instantiation and sharing of services.

Dependency Injection (DI):

• DI is a design pattern in which a class receives its dependencies from an external source rather than creating them itself.
• Angular’s DI system is essential for providing components with the services they depend on.

Creating and Using Services

Let’s explore how to create and use services in an Angular application.

Generate a Service:

• Use the Angular CLI to generate a new service:

ng generate service data

Service Class:

• The generated service class is a plain TypeScript class. You can add methods and properties to encapsulate functionality and data.

// Example of an Angular service
export class DataService {
  private data: string[] = ['item1', 'item2', 'item3'];

  getData(): string[] {
    return this.data;
  }

  addData(newItem: string): void {
    this.data.push(newItem);
  }
}

Injecting a Service:

• Inject the service into a component by adding it to the component’s constructor.

// Example of injecting a service into an Angular component
constructor(private dataService: DataService) { }

Using the Service:

• Utilize the service’s methods or properties within the component.

// Example of using a service in an Angular component
ngOnInit(): void {
  this.items = this.dataService.getData();
}

Singleton Nature of Services

Angular services are singleton objects, meaning there is only one instance of a service in the application.

Shared Instance:

• When a service is injected into multiple components, they all share the same instance of the service.

Conclusion

In this tutorial, we’ve covered the fundamentals of Angular services, including their purpose, dependency injection, and how to create and use services in an Angular application.

In the next tutorial, we’ll explore Angular modules, which help organize and structure an application by grouping related components, directives, and services.

“Angular service basics tutorial”
“Understanding Angular service injection”
“Simple Angular service examples”
“Angular service dependency injection explained”
“Step-by-step guide to Angular services”