Question

我在离子项目中创建了一个提供程序，以从存储中检索用户对象，并在这里找到我的代码

import { Injectable } from '@angular/core';
import { Storage } from '@ionic/storage';

@Injectable()
export class ApiProvider {

  public user: any;

  constructor(
    public storage: Storage
  ) {}

  getStoredUser(){
    this.storage.get('user').then(
      data => {
        this.user = data;
        console.log(data);
      }
    );    
    return this.user;
  }

当我从getStoredUser（）函数通过控制台记录用户对象时，这就是我得到的

{
   authcode: "USR_65267H4390"
   church_id: 2
   email: "test@gmail.com"
   fullname: ""An**a A***e""
   id: 55
   phone: "08*****7"
   skills: "Football, chess, scrabble"
}

json数据正确记录，但是当我尝试在其他组件上进行记录

export class HomePage {

    obj: any;

    userObj:any = {
      name:'',
      email:'', 
      phone:'',
      skills:'',
      unit:'',
      church_id:2 //hardcoded on every request...
    };


  constructor(
    public navCtrl: NavController,
    public api: ApiProvider,
    public storage: Storage
  ) {} 

 ngOnInit():void{     

    this.obj = this.api.getStoredUser();

    //console.log(this.obj) - outputs the object above, no errors..
    //if(this.obj.length < 1)  - gives me error too.. i've tried everything 

    if(this.obj !== null){  //------------ this line gives me error.
        this.userObj = {
          name: this.obj.fullname, // ------- this property gives me error.
          email: this.obj.email, 
          phone: this.obj.phone,
          skills: this.obj.skills,
          unit:'', 
          church_id: this.obj.church_id 
        }
    } else{
      // do something else.
    }

  }

这是我尝试读取全名时遇到的错误...

 " Uncaught(in promise): TypeError: Cannot read property 
 'fullname' of undefined TypeError: at Homepage.webpack.jsonp

这是我尝试读取this.obj的长度时遇到的错误

  " Uncaught(in promise): TypeError: Cannot read property 
  'length' of undefined TypeError: at Homepage.webpack.jsonp...

我已经尝试了所有方法，但我不知道该怎么办。.json对象构造正确，我需要帮助。

Answer 1

方法TypeError: must be real number, not str返回一个promise，而您尝试立即访问它的值。

使用getStoredUser方法解析promise后，您应该访问返回对象：

then

或者如果您与ES7兼容，则使用async\await：

this.api.getStoredUser().then(obj => {
      this.userObj = {
          name: obj.fullname, // ------- this property gives me error.
          email: obj.email, 
          phone: obj.phone,
          skills: obj.skills,
          unit:'', 
          church_id: obj.church_id 
        }
});

Ionic 2 ：：异常的TypeError从Angular中的JSON检索属性

1 个答案: