Angular service injection error for no provider

Question

I have an angular app (v10.1) that is using routing.

In short, I am using modules to take advantage of lazy loading the basic dir structure looks like this

ROOT
    /modules
        /myMod
            myMod.component.ts

the myMod component needs to make use of some services, and so I am trying to include the service (location.service) and declare it in the constructor.

I get an error

core.js:4352 ERROR Error: Uncaught (in promise): 
    NullInjectorError: R3InjectorError(myModModule)[LocationService -> LocationService -> LocationService -> LocationService -> LocationService]: 
    NullInjectorError: No provider for LocationService!

I have tried to add this service to a provider array in @NgModule BUT I have 3 modules to consider ROOT,Resource,myMod

I have tried adding the service to each of these respectively, to no avail - still get the error

Here is a little bit more detailed diagram of the app Please dont tell me I need to add the service to each of the mods, and if Im missusing modules can someone please explain. Thx

ROOT
-app.module
-app-routing.module
-app.component.html (has link routerLink="/resources/myMod" )

-- modules/resources
----resources-routing.module.ts
        const routes: Routes = [{
                path: 'myMod', loadChildren: () => import('../myMod/myMod.module').then((m) => m.myModModule),
            }]

-- modules/myMod
----myMod.module.ts
        import { myModRoutingModule } from './myMod-routing.module';
        import { myModComponent } from './myMod.component';
        @NgModule({
            declarations: [myModComponent],
            imports: [CommonModule, myModRoutingModule]
        })
        export class myModModule {}

----myMod.component.ts
        import { LocationService } from '../../common/services/location.service';
        @Component({
            selector: 'app-myMod',
            templateUrl: './myMod.component.html'
        })
        export class myModComponent implements OnInit {
            constructor( private locationService: LocationService )

https://stackblitz.com/edit/angular-injection-error1

Please include the service class as well, and what version of Angular you're building in. The most likely culprit is that your @Injectable annotation is either missing or is missing the providedIn property. — El-Mo
– El-Mo, Commented Feb 17, 2021 at 1:13

El-Mo · Accepted Answer · 2021-02-17 01:27:28Z

1

It looks like your @Injectable annotation is missing the providedIn property.

Adding it should resolve the issue:

@Injectable({providedIn: 'root'})
export class LocationService {
  ...
}

answered Feb 17, 2021 at 1:27

El-Mo

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9 Comments

j-p Over a year ago

El-mo - that worked - until I added import { HttpClient, HttpHeaders, HttpErrorResponse } from '@angular/common/http'; now that doesnt even work

El-Mo Over a year ago

Is there an error on the console associated with the imports?

j-p Over a year ago

Uncaught (in promise): NullInjectorError: R3InjectorError(CollegesModule)[CollegeService -> CollegeService -> CollegeService -> HttpClient -> HttpClient -> HttpClient]: NullInjectorError: No provider for HttpClient! - this is a college service, loaded right after the location service, that uses httpClient to call the API.

El-Mo Over a year ago

Please update your post with a stackblitz that reproduces the issue.

j-p Over a year ago

well, I cant even get Router working - stackblitz.com/edit/angular-qzdrng

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