Array Element Set

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  myArray: [{name: 'bob', size: 5}],

  bloo: Ember.computed.readOnly('myArray.0'),
  
  whee: Ember.on('init', function() {
  	setTimeout(() => this.set('myArray.0.size', 6), 1000);
  }),
  
  greaterThanFive: Ember.computed.gt('bloo.size', 5)
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
{{bloo.size}} {{greaterThanFive}}
<br>
<br>

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": "2.12.0",
    "ember-template-compiler": "2.12.0",
    "ember-testing": "2.12.0"
  },
  "addons": {
    "ember-data": "3.2.0"
  }
}