What are Angular services

Angular services are a fundamental part of Angular applications that help you to organize and share code across your application. They are typically classes that are instantiated once and shared throughout the application. Services are used to:

1. Encapsulate Business Logic: Services encapsulate the application's business logic and data manipulation tasks. They provide a way to keep components lean by moving functionality out of the components and into services.

2. Share Data: Services allow you to share data between components that need to communicate with each other. They act as a central place where data can be stored and accessed by multiple components.

3. Promote Reusability: Services promote code reusability across your application. The same service can be injected into multiple components, ensuring consistent behavior and reducing code duplication.

4. Handle Application-wide Tasks: Services are ideal for tasks that are not specific to any component, such as logging, data fetching from servers, authentication, caching, etc.

5. Dependency Injection (DI): Angular's dependency injection system makes it easy to inject services into components, other services, or any other class that needs them. This makes components more modular and easier to test.

Creating and Using Angular Services

Here's a basic example of how to create and use an Angular service:

1. Create a Service: Generate a service using Angular CLI or manually create a TypeScript class decorated with @Injectable().

   import { Injectable } from '@angular/core';
   
   @Injectable({
     providedIn: 'root' // Indicates that the service should be provided at the root level
   })
   export class DataService {
     private data: string[] = [];
   
     addData(item: string) {
       this.data.push(item);
     }
   
     getData(): string[] {
       return this.data;
     }
   }
   







2. Inject the Service: Inject the service into a component or another service where it is needed.

   import { Component } from '@angular/core';
   import { DataService } from './data.service';
   
   @Component({
     selector: 'app-example',
     template: `
       <div>
         <button (click)="addData()">Add Data</button>
         <ul>
           <li *ngFor="let item of data">{{ item }}</li>
         </ul>
       </div>
     `
   })
   export class ExampleComponent {
     data: string[] = [];
   
     constructor(private dataService: DataService) {}
   
     addData() {
       this.dataService.addData('New Item');
       this.data = this.dataService.getData();
     }
   }
   

3. Use the Service: Use the service methods and properties within the component.

In this example:

• DataService is a service that manages a list of data items.
• ExampleComponent injects DataService and uses its methods (addData() and getData()) to add data and display it in the template.

Services in Angular are versatile and form a critical part of building scalable and maintainable applications by promoting separation of concerns and reusability of code.