如何使用AngularFire2使路线守卫等待验证检查

我想让我的授权守卫等到我从firebase获得授权后再给我改道。目前，auth-guard检查首先初始化

我需要使它在canActivate中异步，或者只在调用后填充canActivate

auth.guard.ts

import { Injectable } from '@angular/core';
import { Router, CanActivate } from '@angular/router';
import { AuthService } from './auth.service';

@Injectable()
export class AuthGuard implements CanActivate {
    constructor(private authService: AuthService) { 
        console.log(this.authService.isAuthenticated); // returns false, doesn't async
    }

  canActivate() {
      console.log(this.authService.isAuthenticated); // returns false
      return this.authService.isAuthenticated;
  }
}

auth.service.ts

...
import { AngularFire, 
    AuthProviders, 
    AuthMethods, 
    FirebaseListObservable, 
    FirebaseObjectObservable } from 'angularfire2';
...

@Injectable()
export class AuthService {
    isAuthenticated: boolean = false; 
    // the problem is setting it to a bool, need to async it (( but this was from official documentation and Pluralsight tuts__

    constructor(
        public af: AngularFire, 
        private _router: Router, 
        private _route: ActivatedRoute ) { 
           this.af.auth.subscribe((auth)=>{

               console.log('called after after auth guard');

               if (auth == null) {
                   this._router.navigate(['/login']);
               } else {
                   this.isAuthenticated = true;
               }
           }
       });
   }

那么，如何让AuthGuard的canActivate等待异步布尔值呢？ 如何将其传递给AuthGuard的canActivate（）函数？这是Github上一篇文章的答案

auth.service.ts：

@Injectable()
export class AuthService {

  private _user: firebase.User;

  constructor(public afAuth: AngularFireAuth, private db: AngularFireDatabase) {
    afAuth.authState.subscribe(user => this.user = user);  
  }

  get user(): firebase.User {
    return this._user;
  }

  set user(value: firebase.User) {
    this._user = value;
  }

  get authenticated(): boolean {
    return this._user !== null;
  }
}

auth.guard.ts：

@Injectable()
export class AuthGuard implements CanActivate {

  constructor(private auth: AuthService, private router: Router) {}

  canActivate(
    next: ActivatedRouteSnapshot,
    state: RouterStateSnapshot): Observable<boolean> | Promise<boolean> | boolean {
    return this.auth.afAuth.authState
            .take(1)
            .map(authState => !!authState)
            .do(authenticated => {
              if (!authenticated) {
                  this.router.navigate(['login']);
              }
            });
  }
}

@Injectable（）
导出类AuthGuard实现了CanActivate{
构造函数（私有身份验证：身份验证服务，私有路由器：路由器）{}
激活(
下一步：ActivatedRouteSnapshot，
状态：RouterStateSnashot）：可观察的|承诺|布尔值{
返回this.auth.afAuth.authState
.采取（1）
.map（authState=>！！authState）
.do（已验证=>{
如果（！已验证）{
this.router.navigate（['login']）；
}
});
}
}