Slow Route with loading event

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Randomly Slow Route Demo'
});

controllers.slow-route.js

import Ember from 'ember';

export default Ember.Controller.extend({
});

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('slow-route', {path: '/'});
});

export default Router;

routes.slow-route.js

import Ember from 'ember';

const API = [
  {
    data: [1, 2, 3],
    responseTime: 100
  }, {
    data: [100, 200, 300],
    responseTime: 1000
  }, {
    data: [1000, 2000, 3000],
    responseTime: 500
  }];

export default Ember.Route.extend({
  dataVersion: 0,

  model() {
    return new Promise((resolve, reject) => {
      let dataVersion = this.get('dataVersion');
      console.log('REFRESH DATA WITH VERSION', dataVersion, ' (IT WILL TAKE', API[dataVersion].responseTime, 'ms)');

      Ember.run.later(function () {
        let data = API[dataVersion].data;
        console.log('DATA VERSION', dataVersion, 'RETRIEVED: ', data);
        resolve(data);
      }, API[dataVersion].responseTime);
    });
  },

  setupController(controller, model) {
    console.log('SETUP CONTROLLER WITH DATA', model);
    this._super(controller, model);
  },

  actions: {
    loading(transition, route) {
      console.log('LOADING STARTED (', transition.sequence, ')', route.routeName);
      this.controllerFor(route.routeName).set('_loading', true);
      this.set('_loadingSequence', transition.sequence);
      transition.finally(() => {
        console.log('LOADING FINISHED (', transition.sequence, ')');
        if (this.get('_loadingSequence') === transition.sequence) {
          console.log('PAGE LOADED (all remaining transitions will be ignored)');
          this.controllerFor(route.routeName).set('_loading', false);
        }  
      });
    },

    refresh() {
      this.set('dataVersion', 1);
      this.refresh();
      Ember.run.later(() => {
        this.set('dataVersion', 2);
        this.refresh();
      }, 100);
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<div>This demo shows how Ember handles (properly) data retrieval concurrency. Here's what you can do:</div>
<ul>
  <li>Load the page - you should see items 1, 2, 3</li>
  <li>Open browser console (in developer tools) to see debugging messages</li>
  <li>Click the Refresh button - you should see items 1000, 2000, 3000 even though obsolete items 100, 200, 300 are retrieved later</li>
  <li>Check the console - you should see that after obsolete data retrieval setupController is not called (which is correct)</li>
</ul>
<button {{action "refresh"}}>Refresh (from TOP level, you CAN click multiple times fast!)</button>
<br>
{{outlet}}
<br>
<br>

templates.slow-route.hbs

{{#if _loading}}
  <span>Loading...</span>
{{else}}
  <button {{action "refresh"}}>Refresh</button>
  <hr>
  <div>
    <span>Items:</span>
    <ul>
      {{#each content as |item|}}
        <li>{{item}}</li>
      {{/each}}
    </ul>
  </div>
{{/if}}

twiddle.json

{
  "version": "0.12.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.12.0",
    "ember-template-compiler": "2.12.0",
    "ember-testing": "2.12.0"
  },
  "addons": {
    "ember-data": "2.12.1"
  }
}