Extending Computed Properties

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  model() {
    
    // object with computed property
    var Parent = Ember.Object.extend({
      fullName: Ember.computed('first', 'last', function() {
        return `${this.get('first')} ${this.get('last')}`;
      })
    });

    // extending object that leverages original computed property
    // and its own additional logic
    var Child = Parent.extend({
      fullName: Ember.computed('first', 'last', function() {
        return `${this._super(...arguments)} Jr.`;
      })
    });

    const template = {
      first: 'Kilgore',
      last: 'Trout'
    };

    const parent = Parent.create(template);
    const child = Child.create(template);
    
    return {
      parent,
      child
    };
  }
});

templates.application.hbs

<h1>Extending Computed Properties</h1>
<br>
<br>
Parent:
{{model.parent.fullName}}<br>
Child {{model.child.fullName}}
<br>
<br>

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": "2.9.0",
    "ember-data": "2.9.0",
    "ember-template-compiler": "2.9.0",
    "ember-testing": "2.9.0"
  },
  "addons": {}
}