http://stackoverflow.com/questions/42554709/ember-ensure-that-bindings-work-when-setting-properties-in-callback-of-a-custo

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  myService:Ember.inject.service(),
  checkAjaxStatus:Ember.observer('myService.ajaxStatus',function(){
    console.log('checkAjaxStatus ',this.get('myService.ajaxStatus'));
  }),
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  session:Ember.inject.service('my-service'),
  actions:{
    mock(){
      console.log('mock ');
      var self = this;
      var url = self.get('session.url');
      self.set('session.ajaxStatus', 'checking');
      console.log('route: ' + self.get('session.ajaxStatus'));
      Ember.$.ajax({
        url: url,
        type: "GET",
        success: function(response) {
          console.log('success response');
          self.set('session.ajaxStatus', 'success');
          console.log('route: ' + self.get('session.ajaxStatus'));
        },
        error: function(response) {
          self.set('session.ajaxStatus', 'error');
          console.log('route: ' + self.get('session.ajaxStatus'));
        }
      });

    }
  }
});

services.my-service.js

import Ember from 'ember';

export default Ember.Service.extend({
  ajaxStatus:'checking'
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
{{my-component }}
<button {{action 'mock'}}>Mock </button>
<br>
{{outlet}}
<br>
<br>

templates.components.my-component.hbs

{{myService.ajaxStatus}}
{{yield}}

twiddle.json

{
  "version": "0.11.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.10.2",
    "ember-data": "2.11.0",
    "ember-template-compiler": "2.10.2",
    "ember-testing": "2.10.2"
  },
  "addons": {}
}