Angular - данные не остаются при перезагрузке страницы

export class UserListComponent implements OnInit, OnDestroy {
 
  users: User[];
  userSubscription: Subscription;
 
  constructor(private userService: UserService) { }
 
  ngOnInit() {
    this.userSubscription = this.userService.userSubject.subscribe(
      (users: User[]) => {
        this.users = users;
      }
    );
    this.userService.emitUsers();
  }
 
  ngOnDestroy() {
    this.userSubscription.unsubscribe();
  }
 
}

@Injectable()
export class UserService {
  private users: User[] = [
      new User('admin', 'admin', '[email protected]')
  ];
  userSubject = new Subject<User[]>();
 
  emitUsers() {
    this.userSubject.next(this.users.slice());
  }
 
  addUser(user: User) {
    this.users.push(user);
    this.emitUsers();
  }
 
  saveUsersToServer() {
    this.httpClient
      .put('https://TEST.firebaseio.com/users.json', this.users)
      .subscribe(
        () => {
          console.info('Enregistrement terminé !');
        },
        (error) => {
          console.info('Erreur : ' + error);
        }
       );
  }
 
  getUsersFromServer() {
    this.httpClient
      .get<any[]>('https://TEST.firebaseio.com/users.json')
      .subscribe(
        (response) => {
          this.users = response;
          this.emitUsers();
        },
        (error) => {
          console.info('Erreur ! : ' + error);
        }
      );
  }
 
  constructor(private httpClient: HttpClient) { }
 
}