當Ember-Data Store未找到任何記錄時，如何處理錯誤/事件？

Question

情況是：

• session.userID具有正確的ID
• 但是，后端數據庫（Firebase）中沒有用戶數據

這是代碼：

App.ApplicationRoute = Ember.Route.extend({
  model: function() {
    if (this.session.userID) {
      return this.store.find('user', this.session.userID).then(function(_user) {
        console.log('user found', _user);
        return _user;
      }, function(error) {
        // user does not exist or some other error
        console.log('Application Model did not find user in Firebase');
        return null;
      });
    } else {
      console.log('Application Model did not find any session.userID');
      return null;
    }
  },

}); 

我的期望：被告應調用錯誤函數：

function(error) {
  // user does not exist or some other error
  console.log('Application Model did not find user in Firebase');     
});

錯誤：但是，出現以下錯誤：

    Error: no record was found at https://dynamicslife.firebaseio.com/users/facebook%3A931321683548734
        at https://cdn.firebase.com/libs/emberfire/1.2.7/emberfire.min.js:10:3400
        at c (https://cdn.firebase.com/js/client/1.1.2/firebase.js:17:65)
        at https://cdn.firebase.com/js/client/1.1.2/firebase.js:123:689
        at uc (https://cdn.firebase.com/js/client/1.1.2/firebase.js:50:20)
        at Xe (https://cdn.firebase.com/js/client/1.1.2/firebase.js:123:675)
        at Ve.Vb (https://cdn.firebase.com/js/client/1.1.2/firebase.js:123:617)
        at Ye.Vb (https://cdn.firebase.com/js/client/1.1.2/firebase.js:124:418)
        at https://cdn.firebase.com/js/client/1.1.2/firebase.js:139:409
        at https://cdn.firebase.com/js/client/1.1.2/firebase.js:68:878
        at pc (https://cdn.firebase.com/js/client/1.1.2/firebase.js:62:618) ember.js:14876
    Uncaught Error: Assertion Failed: Error: no record was found at https://dynamicslife.firebaseio.com/users/facebook%3A931321683548734 

問題：我知道沒有記錄可以找到。 但是如何處理這種情況並避免引發錯誤呢？ 我的印象是Promise可以讓我在系統崩潰前管理錯誤。

Answer 1

App.ApplicationRoute = Ember.Route.extend({
  model: function() {
    if (this.session.userID) {
      return this.store.find('user', this.session.userID);
    } else {
      console.log('Application Model did not find any session.userID');
      return null;
    }
  },
  afterModel: function(user, transition) {
    if (user.get('length') === 0) {
      console.log('fail');
    } else {
      console.log('success');
    }
  }
});

參見http://emberjs.com/api/classes/Ember.Route.html#method_afterModel