无法检查用户是否在Firebase + Angular中登录

import { Component, OnInit } from '@angular/core';
import { AngularFireAuth } from '@angular/fire/auth';
import { Observable } from 'rxjs';

@Component({
  selector: 'app-login-status',
  template: `
    <div *ngIf="isLoggedIn; else loginForm">
      <p>Welcome, {{ user.displayName }}!</p>
      <button (click)="logout()">Logout</button>
    </div>
    <ng-template #loginForm>
      <p>Please login to continue.</p>
      <!-- Login form goes here -->
    </ng-template>
  `,
})
export class LoginStatusComponent implements OnInit {
  isLoggedIn: boolean = false;
  user: firebase.User | null = null;

  constructor(private afAuth: AngularFireAuth) {}

  ngOnInit() {
    this.afAuth.authState.subscribe((user) => {
      this.isLoggedIn = !!user;
      this.user = user;
    });
  }

  logout() {
    this.afAuth.signOut();
  }
}