cumputedPro

application.controller.js

import Ember from 'ember';

var Person = Ember.Object.extend({
  firstName: null,
  lastName: null,
  age: null,
  country: null,
  dateOfDeath: null,

  fullName: Ember.computed('firstName', 'lastName', function() {
    return `${this.get('firstName')} ${this.get('lastName')}`;
  }),
  
  isDead: Ember.computed('dateOfDeath', {
    get(key) {
      return !!this.get('dateOfDeath');
    },
    set(key, value) {
      if (value) {
      	this.set('dateOfDeath', new Date());
      } else {
        this.set('dateOfDeath', null);
      }
      return value;
    }
  }),

  description: Ember.computed('fullName', 'age', 'country', function() {
    return `${this.get('fullName')}; Age: ${this.get('age')}; Country: ${this.get('country')}`;
  })
});

var captainAmerica = Person.create({
  firstName: 'Steve',
  lastName: 'Rogers',
  age: 80,
  country: 'USA'
});

//document.write(captainAmerica.get('description'));
//document.write('<br> is Dead = ' + captainAmerica.get('isDead'));

captainAmerica.set('isDead', true);

//document.write('<br> date of death ' + captainAmerica.get('dateOfDeath'));

application.template.hbs

{{outlet}}

twiddle.json

{
  "version": "0.5.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.2.0",
    "ember-data": "2.2.0",
    "ember-template-compiler": "2.2.0"
  }
}