How do I inject a service into multiple components in Angular without re-initializing it

Question

Can you explain how I inject a service into multiple components in Angular without re-initializing it?

Answer 1

To inject a service into multiple components in Angular without reinitializing it, you can take advantage of Angular's dependency injection system and the hierarchical injector structure. Here's how you can achieve this:

Provide the Service at the Root Level: Use the @Injectable decorator with the providedIn: 'root' property when defining your service. This ensures that Angular provides a single instance of the service throughout the application.

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

@Injectable({

  providedIn: 'root',

})

export class MyService {

  constructor() {}

}

You can inject this service into any component by adding it to the constructor. Since the service is provided at the root level, Angular will use the same instance in all components.

import { Component } from '@angular/core';

import { MyService } from './my.service';

@Component({

  selector: 'app-example',

  templateUrl: './example.component.html',

})

export class ExampleComponent {

  constructor(private myService: MyService) {}

}

Do not include the service in the providers array of individual components or modules unless you intentionally want a new instance in that specific scope.