Implementing Angular 2 - Steps to ensure a service is accessible within the app module

Question

Implementing Angular 2 - Steps to ensure a service is accessible within the app module

I'm running into an issue trying to utilize a function within a service that I believed was globally accessible. The service in question is named SavedNotificationService:

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

@Injectable()
export class SavedNotificationService {

    private showSavedNotification = false;

    show(): void {
        this.showSavedNotification = true;
    }

    hide(): void {
        this.showSavedNotification = false;
    }

}

I've imported this service in app.module.ts:

import { SavedNotificationService } from "./saved-notification.service";
@NgModule({
providers: [SavedNotificationService]
})

However, when attempting to call a function within the service, it indicates that it cannot be found. Despite making the service available in app.module, do I still need to import it in the specific component where I intend to use it? (Similar to the example below)

@Component({
  providers: [SavedNotificationService]
})

angular typescript

Answer 1

Answer №1

To utilize the service in your component, you must first import it and then inject it as a dependency through the constructor.

It should look something like this:

import { ExampleService } from '....' // where your services reside.

@Component({
    moduleId: module.id,
    selector: 'example-component',
    templateUrl: 'example-component.html'
})
export class ExampleComponent implements OnInit {
    constructor(private _exampleService: ExampleService) { 
    }

For further information on injecting services and working with them, check here.

P.S: By registering your service at a global scope (AppModule), you can inject it anywhere in your application. Alternatively, you can register the service within a specific Module for different injection scopes (be cautious as this may result in multiple instances of the service).

Answer 2

To utilize the service in your component, you must first import it and then inject it as a dependency through the constructor.

It should look something like this:

import { ExampleService } from '....' // where your services reside.

@Component({
    moduleId: module.id,
    selector: 'example-component',
    templateUrl: 'example-component.html'
})
export class ExampleComponent implements OnInit {
    constructor(private _exampleService: ExampleService) { 
    }

For further information on injecting services and working with them, check here.

P.S: By registering your service at a global scope (AppModule), you can inject it anywhere in your application. Alternatively, you can register the service within a specific Module for different injection scopes (be cautious as this may result in multiple instances of the service).

Answer 3

Answer №2

If you define a service in a module, you don't have to declare it again in your component. Simply import the service into your component and initialize it in your constructor like this:

import { SavedNotificationService } from "./saved-notification.service";

@Component({
})
export class ExampleComponent {

  service;

  constructor(service: SavedNotificationService) {

  }
  
  //call the method using this instance
  service.show();
}

Answer 4

If you define a service in a module, you don't have to declare it again in your component. Simply import the service into your component and initialize it in your constructor like this:

import { SavedNotificationService } from "./saved-notification.service";

@Component({
})
export class ExampleComponent {

  service;

  constructor(service: SavedNotificationService) {

  }
  
  //call the method using this instance
  service.show();
}

Implementing Angular 2 - Steps to ensure a service is accessible within the app module

Answer №1

Answer №2

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