Sort by nested property

application.controller.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName:'Ember Twiddle',
  list: Ember.A([
    {
      level1: {
        level2: "one",
        l2Array: [1, 4, 5]
      },
      id:1
    },
    {
      level1: {
        level2: "two",
        l2Array: [5]
      },
      id:2
    },
    {
      level1: {
        level2: "three",
        l2Array: [3,5,3,1]
      },
      id:3
    },
    {
      level1: {
        level2: "three",
        l2Array: [6, 5, 4]
      },
      id:4
    }
  ])
});

application.template.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{my-component list=list}}
<br>
<br>

my-component.component.js

import Ember from 'ember';


export default Ember.Component.extend({
	sortFields: ['level1.l2Array.firstObject'],
  sortedList: Ember.computed.sort('list', 'sortFields')
});

my-component.template.hbs

<ol>
    {{#each list as |item|}}
        <li>{{item.level1.level2}}: {{item.id}}</li>
      {{/each}}
    </ol>

    <ol>
    {{#each sortedList as |item|}}
      <li>{{item.level1.level2}}: {{item.id}}</li>
    {{/each}}
    </ol>

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": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.2.0/ember.debug.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/2.2.0/ember-data.js",
    "ember-template-compiler": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.2.0/ember-template-compiler.js"
  }
}