New Twiddle

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  sum: Ember.computed("a", "b", {
    get() {
      return this.get("a") + this.get("b");
    }
  }),
  subtotal: Ember.computed.readOnly("sum")
});

components.sub-component.js

import Ember from 'ember';

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

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  init() {
  	this._super(...arguments);
  },
  appName: 'Ember Twiddle',
  delayed: Ember.computed(() => {
    let promise = new Ember.RSVP.Promise(resolve => setTimeout(() =>  resolve({a: 40, b: 50}), 1000));
    return DS.PromiseObject.create({ promise});
  })
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>

{{#my-component a=delayed.a b=delayed.b as |data|}}
{{sub-component subtotal=data.subtotal}}
{{/my-component}}

templates.components.my-component.hbs

<h3>my-component</h3>
{{yield (hash sum=sum subtotal=subtotal)}}

templates.components.sub-component.hbs

<h3>sub-component</h3>
{{yield}}
{{subtotal}}

twiddle.json

{
  "version": "0.10.6",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://s3.amazonaws.com/builds.emberjs.com/release/ember.prod.js",
    "ember-data": "2.10.0",
    "ember-template-compiler": "release",
    "ember-testing": "release"
  },
  "addons": {}
}