Angular 7 Routes with Resolvers don't load Components

Question

I'm having an Angular 7 issue where a module's child components that have a resolver on the route don't load.

app-routing.module.ts

{
  path: 'Account',
  loadChildren: './account/account.module#AccountModule'
}

account-routing.module.ts

{
  path: 'Profile',
  component: ProfileComponent,
  resolve: {
    profile: ProfileResolver
  }
}

profile.resolver.ts

@Injectable()
export class ProfileResolver implements Resolve<Profile> {

  constructor(private readonly accountService: AccountService) {
  }

  resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<Profile> {
    return this.accountService.profile();
  }
}

profile.component.ts

@Component({
⋮
})
export class ProfileComponent implements OnInit {

  model: Profile;

  constructor(private readonly route: ActivatedRoute) {
  }

  ngOnInit(): void {
    this.model = this.route.snapshot.data['profile'] as Profile;
  }
}

account.service.ts

@Injectable()
export class AccountService {

  constructor(protected readonly http: HttpClient) {
  }

  profile(): Observable<Profile> {
    return this.http.get<Profile>(`${environment.apiUrl}/Account/Profile`);
  }
}

The behavior is that, when navigating to /Account/Profile, the ProfileResolver is called, hits the server, and gets a 200 response with the Profile object (I can see it in the Network tab), and then... nothing. Neither the constructor or the ngOnInit method of ProfileComponent are called.

If I remove the ProfileResolver from the AccountRoutingModule and call the AccountService directly from the ngOnInit method, it works. But there are a number of template parse errors from the template while it waits for the response (which is the whole reason I want to use the resolve).

Is there something extra I need to do to make a resolver work with these modules?

This might also be the same issue as described here: Angular Router don't load component with resolver

UPDATE: I turned on enableTracing so I could see what is happening. Here is the output:

Router Event: NavigationStart
NavigationStart(id: 2, url: '/Account/Profile')
NavigationStart {id: 2, url: "/Account/Profile", navigationTrigger: "imperative", restoredState: null}

Router Event: RoutesRecognized
RoutesRecognized(id: 2, url: '/Account/Profile', urlAfterRedirects: '/Account/Profile', state: Route(url:'', path:'') { Route(url:'Account', path:'Account') { Route(url:'Profile', path:'Profile') }  } )
RoutesRecognized {id: 2, url: "/Account/Profile", urlAfterRedirects: "/Account/Profile", state: RouterStateSnapshot}

Router Event: GuardsCheckStart
GuardsCheckStart(id: 2, url: '/Account/Profile', urlAfterRedirects: '/Account/Profile', state: Route(url:'', path:'') { Route(url:'Account', path:'Account') { Route(url:'Profile', path:'Profile') }  } )
GuardsCheckStart {id: 2, url: "/Account/Profile", urlAfterRedirects: "/Account/Profile", state: RouterStateSnapshot}

Router Event: ChildActivationStart
ChildActivationStart(path: '')
ChildActivationStart {snapshot: ActivatedRouteSnapshot}

Router Event: ActivationStart
ActivationStart(path: 'Profile')
ActivationStart {snapshot: ActivatedRouteSnapshot}

Router Event: GuardsCheckEnd
GuardsCheckEnd(id: 2, url: '/Account/Profile', urlAfterRedirects: '/Account/Profile', state: Route(url:'', path:'') { Route(url:'Account', path:'Account') { Route(url:'Profile', path:'Profile') }  } , shouldActivate: true)
GuardsCheckEnd {id: 2, url: "/Account/Profile", urlAfterRedirects: "/Account/Profile", state: RouterStateSnapshot, shouldActivate: true}

Router Event: ResolveStart
ResolveStart(id: 2, url: '/Account/Profile', urlAfterRedirects: '/Account/Profile', state: Route(url:'', path:'') { Route(url:'Account', path:'Account') { Route(url:'Profile', path:'Profile') }  } )
ResolveStart {id: 2, url: "/Account/Profile", urlAfterRedirects: "/Account/Profile", state: RouterStateSnapshot}

So it looks like the ResolveEnd event is never firing. I found this issue: Router's ActivatedRoute data returns empty {} if module is lazy. It seems like it may be related but I'm not sure how I would implement that fix here.

Answer 1

I consulted the Routing & Navigation guide again and changed my Resolver to look like it does there:

profile.resolver.ts

@Injectable()
export class ProfileResolver implements Resolve<Profile> {

  constructor(private readonly accountService: AccountService) {
  }

  resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<Profile> {
    return this.accountService.profile().pipe(
      take(1),
      map((profile: Profile) => profile));
  }
}

The key was adding the take(1). Without this, the ResolveEnd event is never fired and the Router just hangs.