New Twiddle

controllers.application.js

import Ember from 'ember';
import RSVP from 'rsvp';

const PromiseArrayProxy = Ember.ArrayProxy.extend(Ember.PromiseProxyMixin);

function generatePromise() {
  return new RSVP.Promise((resolve) => {
    setTimeout(() => resolve(['one', 'two', 'three']), 5000);
  });
}


function generatePromiseProxy() {
  let promise = generatePromise();
  return PromiseArrayProxy.create({
    content: [],
    promise
  });
}


export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  promise: ['initial', 'values'],
  actions: {
    refreshCollection() {
      this.set('promise', generatePromiseProxy());
    }
  }  
});

templates.application.hbs

<div id="ember-basic-dropdown-wormhole"></div>
<h1>Welcome to {{appName}}</h1>
<br>
<br>
<button onclick={{action "refreshCollection"}}>Refresh collection</button>
<br>
Default loading message
{{#power-select
  options=promise
  selected=selected
  onchange=(action (mut selected))
  as |name|
}}
  {{name}}
{{/power-select}}
<br>
Custom loading message (press the <code>Refresh Collection</code> button and open this select)
{{#power-select
  options=promise
  loadingMessage="Waiting for the server...."
  selected=selected
  onchange=(action (mut selected))
  as |name|
}}
  {{name}}
{{/power-select}}

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",
    "ember-power-select": "1.9.7"
  }
}