changing options

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  options: [
    { groupName: 'Group 1', options: Ember.A(['option 1', 'option 2']), },
    { groupName: 'Group 2', options: Ember.A(['option 5', 'option 3']), },
  ].map(i => Ember.Object.create(i)),

  optionsObserver: Ember.observer('options.@each.options.[]', function() {
    console.log('change registered');
  }),
  
  sortedOptions: Ember.computed('options.[]', function() {
    this.get('options').forEach(group => {
      group.set('options', group.options.sortBy('name'));
    });
    return this.get('options').sortBy('groupName');
  }),
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
<br>
  {{#each sortedOptions as |group|}}
    <b>{{group.groupName}}:</b>
    <ul>
      {{#each group.options as |opt|}}
        <li>{{opt}}</li>
      {{/each}}
    </ul>
  {{/each}}
<br>

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2"
  }
}