The child module's services are accessible and utilized by the components of the parent module

Question

The child module's services are accessible and utilized by the components of the parent module

I have an Angular application structured as follows:

Data Module
     --> Data Component
     --> Data Service
List Module
  --> imports Data Module
   --> List Component
          --> which calls Data Component
   --> Parent List Component
          --> which in turn calls List Component

The Data service functions correctly when using the List component.
However, when using the Parent List component, it renders the List component which then renders the Data component. The issue is that the Data service is shared and behaves in the same way as step 1.

It seems like I should have created a separate instance of the Data service.

If you have any suggestions or insights on what I might be missing, they would be greatly appreciated.

Thank you.

angular typescript

Answer 1

Answer №1

The extent of your service's reach is determined by how and where you choose to offer it.

If you specify your service as providedIn: 'root', only a single global instance will be generated and utilized across all modules or components where the service is supplied.

@Injectable({
  providedIn: 'root'
})
class DataService {
    // A unique DataService accessible throughout various modules
}

Alternatively, you can limit a service's scope by adjusting the value of providedIn. For more information, visit this documentation link.

You may also opt to exclude the providedIn parameter altogether, enabling you to provide the service at the component level. Consider the following example:

// Service declared as @Injectable without providedIn
@Injectable()
class DataService {
    // The service remains inactive until instantiated within a specific component
}

In this scenario, the service will be created only when included in a component's providers array, like so:

@Component({
  selector: 'app-list',
  template: ``,
  styleUrl: ``,
  providers: [
    DataService
  ]
})
export class ListComponent {
  constructor(private dataService: DataService) {}
}

@Component({
  selector: 'app-parent-list',
  template: `<app-list></app-list>`,
  styleUrl: ``,
})
export class ParentListComponent {
  constructor(private dataService: DataService) {}
}

This setup ensures that DataService is instantiated solely upon creation of a ListComponent, with the instance being discarded once the associated ListComponent is destroyed.

Answer 2

The extent of your service's reach is determined by how and where you choose to offer it.

If you specify your service as providedIn: 'root', only a single global instance will be generated and utilized across all modules or components where the service is supplied.

@Injectable({
  providedIn: 'root'
})
class DataService {
    // A unique DataService accessible throughout various modules
}

Alternatively, you can limit a service's scope by adjusting the value of providedIn. For more information, visit this documentation link.

You may also opt to exclude the providedIn parameter altogether, enabling you to provide the service at the component level. Consider the following example:

// Service declared as @Injectable without providedIn
@Injectable()
class DataService {
    // The service remains inactive until instantiated within a specific component
}

In this scenario, the service will be created only when included in a component's providers array, like so:

@Component({
  selector: 'app-list',
  template: ``,
  styleUrl: ``,
  providers: [
    DataService
  ]
})
export class ListComponent {
  constructor(private dataService: DataService) {}
}

@Component({
  selector: 'app-parent-list',
  template: `<app-list></app-list>`,
  styleUrl: ``,
})
export class ParentListComponent {
  constructor(private dataService: DataService) {}
}

This setup ensures that DataService is instantiated solely upon creation of a ListComponent, with the instance being discarded once the associated ListComponent is destroyed.

The child module's services are accessible and utilized by the components of the parent module

Answer №1

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The child module's services are accessible and utilized by the components of the parent module

Answer №1

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