Need injection token for something provided in root

Issue

I have a service that is used throughout my app to do admin functions. Normally all I have to do to use it is add it to the list of parameters of a constructor.

like so

constructor(private adminService: AdminService) { }

Which is exactly what is shown in the angular.io documentation

However I needed to use it a bit earlier on, like right after authentication and I am getting a weird error that I have no idea how to resolved based on the documentation.

The error message

 No suitable injection token for parameter 'adminService' of class 'LandingLayoutComponent'

admin.service.ts

    @Injectable({
      providedIn: 'root'
    })
    export class AdminService {}
    constructor(private httpService: ApplicationHttpClient) { }

app.module.ts

@NgModule({
  declarations: [
    AppComponent,
    LandingLayoutComponent,
  ],
  imports: [],
  providers: [
    ApplicationHttpClient,
  ],
  bootstrap: [AppComponent]
})

Update, shared module does it differently.

providers: [
  {
    provide: ApplicationHttpClient,
    useFactory: applicationHttpClientCreator,
    deps: [HttpClient, AuthenticationService, ProgressBarService]
  }],

Solution

I'm curious as to what your ApplicationHttpClient looks like. Does it use the HttpClient class? If so, then you probably should also include the HttpClientModule in your Application Module.

Answered By - Rcdlb