New Twiddle

controllers.application.js

import Ember from 'ember';

var MyObj = Ember.Object.extend({
	value: null,
  
  depends: null,
  
  value2: Ember.computed('depends', {
    get() {
      var depends = this.get('depends') || {};
      return Ember.computed(...Object.keys(depends).map(d=> `depends.${d}`), { 
          get() { 
            return Object.values(depends); 
          }
        }
      );
    }
  }),
 
  init() {
  	this._super();
    var depends = this.get('depends') || {};
    /*this.set('value', Ember.computed(...Object.keys(depends).map(d=> `depends.${d}`), { 
      	get() { 
      		return Object.values(depends); 
    		}
    	}
    ));*/
    
    Ember.defineProperty(this, 'value', Ember.computed(...Object.keys(depends).map(d=> `depends.${d}`), { 
      	get() { 
      		return Object.values(depends); 
    		}
    	}
    ));
  }
});

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
             
  obj: MyObj.create({depends: {coco: 'coco', test: 'test'}}),
  actions:{
    change() {
    	this.set('obj.depends.coco', 'salut!');
    }
  }
});

templates.application.hbs

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

<p>
obj.value: {{obj.value}}
</p>

<p>
obj.value2: {{obj.value2}}
</p>

<p>
<button {{action 'change'}}>change coco</button>
</p>

twiddle.json

{
  "version": "0.15.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.2.2",
    "ember-template-compiler": "3.2.2",
    "ember-testing": "3.2.2"
  },
  "addons": {
    "ember-data": "3.2.0"
  }
}