What is a service in Angular?

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In Angular, services are used to provide a common functionality to various modules. A service provides better modularity for your app by allowing you to extract common functionality out of components.

Let’s see how to create a service which can be used across multiple components. Here, service name is EgService.

In Angular, a service is a class that encapsulates reusable functionality and can be injected into components, directives, or other services. Services are used to promote modularity, maintainability, and reusability in Angular applications.

Key points to include in your answer about Angular services:

  1. Encapsulation of Reusable Functionality: Services encapsulate a specific functionality or feature set that can be reused throughout an application.
  2. Singleton Instances: By default, Angular services are singleton instances. This means that there is only one instance of a service created and shared throughout the application.
  3. Dependency Injection (DI): Services are typically injected into components or other services using Angular’s dependency injection system. This promotes loose coupling between components and services, making the application more modular and easier to maintain.
  4. Common Use Cases: Services are commonly used for tasks such as data fetching from APIs, sharing data between components, implementing business logic, and managing application state.
  5. @Injectable Decorator: To make a class injectable as a service, it needs to be decorated with the @Injectable() decorator provided by Angular.

Example:

typescript
import { Injectable } from '@angular/core';

@Injectable({
providedIn: 'root' // providedIn: 'root' ensures that the service is available throughout the application
})
export class MyService {
constructor() { }

// Methods and properties of the service
}

When asked about services in an Angular interview, be prepared to discuss how services are implemented, why they are useful, how they are injected into components, and provide examples of scenarios where services would be beneficial in an Angular application.