Как получить тип пользователя из Firestore и направить пользователя на соответствующую страницу в Angular

Question

Весь код страницы

    import { Component, OnInit } from '@angular/core';
        import { AngularFirestore, DocumentReference } from '@angular/fire/firestore';
        import { Observable, of, from } from 'rxjs';
        import { IGreetAllUser } from '../models/igreetAllUser';
        import { User } from 'src/app/auth/models/user';
        import { flatMap, switchMap } from 'rxjs/operators';
        import { Router } from '@angular/router';
        import { AutheroizeService } from 'src/app/auth/services/autheroize.service';
        import { AngularFireAuth } from '@angular/fire/auth';


        interface GreetAll {
          admin: boolean;
          country: string;
          firstName: string;
          lastName: string;
          userEmail: string;
          userId: string;
          userType: string;
        }

        interface RootObject {
          greetAll: GreetAll;
        }

        @Component({
          selector: 'app-test',
          templateUrl: './test.component.html',
          styleUrls: ['./test.component.css']
        })
        export class TestComponent implements OnInit {

          userData;
          user$: Observable<User>;
          greetAllUsersInServer = [];
          singleUserFromServer = [];
          localUser;
          userEmail;
          currentUser;
          savedUser;
          myUser: IGreetAllUser;
          myUserAfterStringConversion;
          private userRef: DocumentReference;
          greetAllUsersInServerINBDE: Observable<any[]>;





          constructor(private afAuth: AngularFireAuth,
            private db: AngularFirestore,
            private afs: AngularFirestore,
            private _router: Router,
            private _authorizeService: AutheroizeService) { }

          ngOnInit() {
            console.log('Test Component.ts working now')
            this.fetchUser().catch(error => console.log(error));
          }

-> Мне нужна помощь в этой функции

Я не могу направить пользователя на соответствующую страницу, не обновив страницу. Я хочу, чтобы это происходило без обновления.

    async  fetchUser() {
                try {
                  const localStorageUser = await this.checkLocalStorage();
                  if (localStorageUser == null ){

                    const settingUserFromServer = await this.serverUser$();
                    const localStorageUser = await this.checkLocalStorage();
                    const userEmail = await localStorageUser.email;
                    const userType = await this.selectedClient(userEmail);
                    const last = await this.directToRespectivePage(userType);
                    console.log('second last' + userType);
                      } else {
                        const userEmail = await localStorageUser.email;
                        const userType = await this.selectedClient(userEmail);
                        const last = await this.directToRespectivePage(userType);
                        console.log('last' + userType);
                      }
                } catch (error) {
                  return { name: 'Default' }
                }
              }

> вызов сервера для поиска типа пользователя

          serverUser$() {
            this.afAuth.authState.subscribe(user => {
              if (user) {
                this.userData = user;
                localStorage.setItem('user', JSON.stringify(this.userData));
                const userServer = JSON.stringify(localStorage.getItem('user'));

                return userServer;
              } else {
                localStorage.setItem('user', null);
              }
            })

          }

> проверка локального хранилища для типа пользователя

    checkLocalStorage() {
                if (localStorage.getItem("user") === null) {
                    return null
                } else {
                  const user = JSON.parse(localStorage.getItem('user'));
                  console.log(user);
                  return user;
                }
              }

> наконец, обнаружив тип пользователя

    selectedClient(email: string) {
                if (email == null) {
                  return null
                } else {
                  const snapshotResult = this.db.collection('greetAll', q =>
                    q.where('greetAll.userEmail', '==', email)
                      .limit(1))
                    .snapshotChanges()
                    .pipe(flatMap(greetAllUsersInServerINBDE => greetAllUsersInServerINBDE));
                  snapshotResult.subscribe(doc => {
                    this.myUser = <IGreetAllUser>doc.payload.doc.data();
                    this.userRef = doc.payload.doc.ref;
                    if (this.myUser.greetAll.userEmail != null) {
                      return this.myUser.greetAll.userType;
                    } else {
                      return null
                    }
                  });
                }

              }

> направляя пользователя на его собственную страницу

    directToRespectivePage(utype: string) {
                console.log('direct to respective page has received value ' + utype);
                 if (utype == "student") {
                  this._router.navigate(['wlecomeStudent']);
                } else if (utype == "faculty") {
                  this._router.navigate(['welcomeFaculty']);
                } else if (utype == "admin") {
                  this._router.navigate(['welcomeAdmin']);
                } else if (utype == null) {
                  this._router.navigate(['greetAllUsers']);
                }
              }

-> проверяя, существует ли пользователь

    checkIfUserExists() {
                this._authorizeService.getUser();
                this.localUser = JSON.parse(localStorage.getItem('user'));
                this.db.collection(`greetAll`, q => q.where(`greetAll.userEmail`, `==`, this.localUser.email)
                ).snapshotChanges().subscribe(serverItems => {
                  this.singleUserFromServer;
                  serverItems.forEach(a => {
                    let item: any = a.payload.doc.data();
                    item.id = a.payload.doc.id;
                    this.singleUserFromServer.push(item);
                  })
                  if (this.singleUserFromServer.length > 0) {
                    this.currentUser = this.singleUserFromServer;
                    this.selectedClient(this.savedUser)    
                  } else {
                    this._router.navigate(['greetAllUsers']);
                  }
                })      
              }   
            }