@Injectable()
export class CanAdminProvide implements CanActivate {

  constructor(private userSrv: UserService, private msg: NzMessageService) {}

  canActivate(
    route: ActivatedRouteSnapshot,
    state: RouterStateSnapshot): boolean | Observable<boolean> | Promise<boolean> {
    return new Observable((observer) => {
      // 拥有 `admin` 角色
      if (this.userSrv.hasRole('admin')) {
        observer.next(true);
        observer.complete();
        return;
      }

      this.msg.error('授权不足');
      observer.next(false);
      observer.complete();
    });
  }

}

@Injectable()
export class CanLeaveProvide implements CanDeactivate<GuardComponent> {
  constructor (private confirmSrv: NzModalService) {}

  canDeactivate(
    component: GuardComponent,
    currentRoute: ActivatedRouteSnapshot,
    currentState: RouterStateSnapshot,
    nextState?: RouterStateSnapshot): boolean | Observable<boolean> | Promise<boolean> {
    return new Observable((observer) => {
      this.confirmSrv.confirm({
        title: '确认要离开吗？',
        content: '你已经填写了部分表单离开会放弃已经填写的内容。',
        okText: '离开',
        cancelText: '取消',
        onOk: () => {
          observer.next(true);
          observer.complete();
        },
        onCancel: () => {
          observer.next(false);
          observer.complete();
        }
      });
    });
  }
}

// 允许
observer.next(true); 
// 或拒绝
// observer.next(false);

observer.complete();

@Injectable()
export class CanAuthProvide implements CanActivate, CanLoad {

  constructor(private userSrv: UserService, private msg: NzMessageService) {}

  check(): Observable<boolean> {
    return new Observable((observer) => {
      if (this.userSrv.isLogin) {
        observer.next(true);
        observer.complete();
        return;
      }

      this.msg.error('权限不足');
      observer.next(false);
      observer.complete();
    });
  }

  canActivate(
    route: ActivatedRouteSnapshot,
    state: RouterStateSnapshot): boolean | Observable<boolean> | Promise<boolean> {
    return this.check();
  }

  canLoad(route: Route): boolean | Observable<boolean> | Promise<boolean> {
    return this.check();
  }

}

{ path: 'auth', component: GuardAuthComponent, canActivate: [ CanAuthProvide ] },
{ path: 'admin', loadChildren: './admin/admin.module#AdminModule', canLoad: [ CanAuthProvide ] }