CODEWITHSUNDEEP
angulartypescript
Fabianus
Fabianus

Reputation: 723

function undefined that should be there?

I have an object of type "user" that should have a function "getPermission()". During runtime (of Angular 7) it throws the error "TypeError: this.user.getPermission is not a function".

Here ist what seems to me to be the essential context:

My user class: 

export class User  {
   ...
   public getPermission(): boolean {
      return true;
   }
   ...
}

I have a service from which I fetch a user from the api (which is asp.net core): 

 getUser(id): Observable<User> {
   return this.http.get<User>(this.baseurl + 'user/' + id);
 }

then I have a resolver: 

@Injectable()
export class UserEditResolver implements Resolve<User> {
   constructor(private userService: UserService, private authService: AuthService,
       private router: Router,
       private alertify: AlertifyService) {}

   resolve(route: ActivatedRouteSnapshot): Observable<User> {
       return this.userService.getUser(this.authService.decodedToken.nameid).pipe(
           catchError(error => {
               this.alertify.error('Problem retrieving your data');
               this.router.navigate(['/users']);
               return of(null);
           })
       );
   }
}

and finally in my component I call the function getPermission: 

 user: User;

 ngOnInit() {

   this.route.data.subscribe(data => {
     this.user = data['user'];
   });

   const t: boolean = this.user.getPermission();
 }

And as written above, I get the error: 

TypeError: this.user.getPermission is not a function

Beside the function and all other functions which are not present at runtime, all properties loaded from the api are there.

I would be so thankful for any hit how this could happen !

Upvotes: 1

Views: 231

Answers (2)

unional
unional

Reputation: 15599

TypeScript only exists in compile time. It does not do anything in runtime.

Simply doing this.http.get<User>(...) will not convert anything you received to the class User you specify.

You need to parse the input yourself and instantiates the User instance.

Upvotes: 3

Sachila Ranawaka
Sachila Ranawaka

Reputation: 41445

create an instance of the class

user: User = new User();

Upvotes: 0

Related Questions