使用角度4访问firebase中的数据

Question

当我使用angular 4时，我可以访问firebase中的数据... 在规则firebase我修改为：

  

{     “规则”：{       “.read”：是的，       “.write”：是的     }   }

但也有错误我显示数据Firebase，我有这个结果：

enter image description here

代码服务：

import { Injectable } from '@angular/core';
    import { AngularFireDatabase, AngularFireList} from 'angularfire2/database';
    import { FirebaseListObservable, FirebaseObjectObservable } from 'angularfire2/database-deprecated';
    import { Observable} from 'rxjs';
    import { Employee } from '../Employee';

    @Injectable()
    export class EmployeeService {

    employees:AngularFireList<any[]>;
    Employee:FirebaseObjectObservable<any>;

      constructor(public af:AngularFireDatabase) {
        this.employees = this.af.list('/employeesdb') ;
       }

       getEmployees(){
        return this.employees;
       }

    }

代码组件：

import { Component, OnInit } from '@angular/core';
    import { EmployeeService } from '../../services/employee.service';
    import { Employee } from '../../Employee';

    @Component({
      selector: 'app-employees',
      templateUrl: './employees.component.html',
      styleUrls: ['./employees.component.css']
    })
    export class EmployeesComponent implements OnInit {
    employees: Employee[];

      constructor(public employeeService: EmployeeService) { 

      }

      ngOnInit() {
        /*this.employeeService.getEmployees().subscribe(employees => {
            this.employees = employees;
        });*/
        console.log(this.employeeService.getEmployees());

      }

    }