Angular - Response is not assignable to type 'request?: HttpRequest<any>

I try to write an AuthGuard in Angular but i get the following Error:

Type 'typeof AuthServiceService' is not assignable to type '(request?: HttpRequest) => string | Promise'. Type 'typeof AuthServiceService' provides no match for the signature '(request?: HttpRequest): string

This is my auth-service.service.ts:

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

  constructor(
    private http:HttpClient,
    public jwtHelper: JwtHelperService) { }
  login(data):Observable<any>{
    return this.http.post(baseUrl + 'ApplicationUser/login' ,data)

  }

  handleError(error: HttpErrorResponse) {
    return throwError(error);
  }

  public isAuthenticated(): boolean {
    const token = localStorage.getItem('token');
    return !this.jwtHelper.isTokenExpired(token);
  }

}

Here is my AuthGuard Service:

import { AuthServiceService } from 'src/services/auth/auth/auth-service.service';
import { Injectable } from '@angular/core';
import { CanActivate, Router } from '@angular/router';

@Injectable({
  providedIn: 'root'
})
export class AuthGuardService implements CanActivate {

  constructor(public auth: AuthServiceService, public router: Router) { }
  
  canActivate(): boolean {
    if (!this.auth.isAuthenticated()) {
      this.router.navigate(['']);
      return false;
    }
    return true;
  }
}

I get this error on this line on tokenGetter:

const JWT_Module_Options: JwtModuleOptions = {
  config: {
    tokenGetter: AuthServiceService
  }
};

Can somebody help me what the response from AuthService should look like?

After some research i have found the solution. The tokenGetter Option needs a string with my token - so i returned the token from the local storage like below:

const JWT_Module_Options: JwtModuleOptions = {
  config: {
    tokenGetter: () => {
      return localStorage.getItem('token')
    }
  }
};

Now my AuthGuard works as expected :) Thank you all for help! :)