computed-properties

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  // exposes the problem I was seeing on
  // http://stackoverflow.com/q/41515493/7355
  averageNapDuration: function() {
    console.log('nap called');
		return 124;
  },
  
  averageNightDuration: Ember.computed('model', function() {
    console.log('night called');
		return 123;
  })
});

templates.application.hbs

nap: {{averageNapDuration}}<br>
night: {{averageNightDuration}}

twiddle.json

{
  "version": "0.10.7",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.10.0",
    "ember-data": "2.10.0",
    "ember-template-compiler": "2.10.0",
    "ember-testing": "2.10.0"
  },
  "addons": {}
}