Angular canActivate从服务中获取更新的变量

import { Injectable } from '@angular/core';
import { CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot, UrlTree } from '@angular/router';
import { Observable } from 'rxjs';
import { AuthService } from './auth.service';

@Injectable({
  providedIn: 'root'
})
export class AuthGuard implements CanActivate {
  constructor(private authService: AuthService) {}

  canActivate(
    next: ActivatedRouteSnapshot,
    state: RouterStateSnapshot): Observable<boolean | UrlTree> | Promise<boolean | UrlTree> | boolean | UrlTree {
    return this.authService.isLoggedIn$.pipe(
      map(isLoggedIn => {
        // 根据isLoggedIn的值进行相应的权限控制
        if (isLoggedIn) {
          return true; // 允许导航
        } else {
          // 重定向到登录页面
          return this.router.parseUrl('/login');
        }
      })
    );
  }
}