loading substate

controllers.application.js

import Ember from 'ember';

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

router.js

import Ember from 'ember';
import config from './config/environment';

const Router = Ember.Router.extend({
  location: 'none',
  rootURL: config.rootURL
});

Router.map(function() {
  this.route('feed');
});

export default Router;

routes.feed.js

import Ember from 'ember';

export default Ember.Route.extend({
  model() {
    var myPromise = new Ember.RSVP.Promise(function(resolve) {
      setTimeout(resolve, 3000);
    });
    
    return myPromise;
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{#link-to 'application'}}home{{/link-to}}
{{#link-to 'feed'}}feed{{/link-to}}
<hr />
{{outlet}}

templates.feed.hbs

FEED!

templates.feed_loading.hbs

feed loading.

twiddle.json

{
  "version": "0.10.4",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.7.0",
    "ember-data": "2.7.0",
    "ember-template-compiler": "2.7.0"
  },
  "addons": {}
}