从firestore获取数据并在屏幕上显示的问题

Question

我在控制台中不断得到的错误是：

core.js:6241 ERROR firebaseerror：不能使用空路径调用函数collectionreference.doc（）。

我的firestore设计:
集合名称“用户”->包含每个用户的文档->每个用户都有“联系人”集合->每个联系人包含电子邮件、姓名、电话联系人属性。

export class CrudService {
  constructor(private authservice: AuthService, public fireservices:AngularFirestore) { }
  
  //create_NewContact adds to the 'contacts' collection in firebase, the contact that the user entered as input
  create_NewContact(Record)
  {  
    return this.fireservices.collection('users').doc(this.authservice.currentUserId).collection('contacts').add(Record);
  }

  //get_AllContacts gets the 'contacts' collection from firebase
  get_AllContacts()
  {
    return this.fireservices.collection('users').doc(this.authservice.currentUserId).collection('contacts').snapshotChanges();
  }
.
.
.
}

export class ContactListComponent implements OnInit {
  contact: any;
  contactName: string;
  contactEmail: string;
  contactPhone: string;
  message:string;
  
  constructor(private authservice: AuthService,public crudservice:CrudService) { }
  
  ngOnInit() {
    this.crudservice.get_AllContacts().subscribe(data => {
      this.contact = data.map(c => {
        return {
          id: c.payload.doc.id,
          isEdit: false,
          name: c.payload.doc.data()['name'],
          email: c.payload.doc.data()['email'],
          phone: c.payload.doc.data()['phone'],
        };
      })
      console.log(this.contact);
    });
  }
  
  /*CreateRecord() will fire after the user press the "Create Contact" btn*/
  CreateRecord()
  {
    //The function stores within the relevant fields in "Record" variable, the user's input
    let Record = {};
    Record['name'] = this.contactName;
    Record['email'] = this.contactEmail;
    Record['phone'] = this.contactPhone;
    
    //create_NewContact is defined in crud.service.ts file
    this.crudservice.create_NewContact(Record).then(res => {
      this.contactName = "";
      this.contactEmail = "";
      this.contactPhone = "";
      console.log(res);
      this.message = "Contact data save done";
    }).catch(error => {
      console.log(error);
    })
  }
.
.
.
}

Answer 1

错误消息表明传递给doc()方法的值是空字符串。

问题很可能来自这样一个事实，即在调用此方法时，this.authService.currentUserID为空。CurrentUserID可能为null，因为AuthService对象尚未完成初始化：有关详细信息，请参阅文档。

您应该使用onAuthStateChanged观察器，或者检查this.authService.currentUserid是否为空。