@rwjblue- App Level Loading Templates

application-loading.template.hbs

<h5>application-loading template</h5>

application.controller.js

import Ember from 'ember';

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

application.route.js

import Ember from 'ember';

export default Ember.Route.extend({
	model() {
    return new Ember.RSVP.Promise((resolve) => {
      setTimeout(resolve, 500);
    });
  }
});

application.template.hbs

<h1>Welcome to {{appName}}</h1>
{{link-to 'foo.bar (fast)' 'foo.bar'}} | {{link-to 'foo.bar.baz (slow: shows -loading)' 'foo.bar.baz'}} | {{link-to 'foo.bar.qux (slow: shows parent loading)' 'foo.bar.qux'}}
<br>
<br>
{{outlet}}
<br>
<br>

foo.bar.baz-loading.template.hbs

<h5>foo.bar.baz-loading template</h5>

foo.bar.baz.route.js

import Ember from 'ember';

export default Ember.Route.extend({
  model() {
    return new Ember.RSVP.Promise((resolve) => {
      setTimeout(resolve, 500);
    });
  }
});

foo.bar.baz.template.hbs

<h5>foo.bar.baz template</h5>

foo.bar.loading.template.hbs

<h5>foo.bar.loading template</h5>

foo.bar.qux.route.js

import Ember from 'ember';

export default Ember.Route.extend({
  model() {
    return new Ember.RSVP.Promise((resolve) => {
      setTimeout(resolve, 500);
    });
  }
});

foo.bar.qux.template.hbs

<h5>foo.bar.qux template</h5>

foo.bar.template.hbs

<h4>foo.bar route</h4>
{{outlet}}

router.js

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

var Router = Ember.Router.extend({
  location: config.locationType
});

Router.map(function() {
  this.route('foo', function() {
    this.route('bar', function() {
      this.route('baz');
      this.route('qux');
    });
  });
});

export default Router;

twiddle.json

{
  "version": "0.4.9",
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/1.13.9/ember.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/1.13.11/ember-data.js",
    "ember-template-compiler": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/1.13.9/ember-template-compiler.js"
  }
}