NotifyPropertyChanged

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  myStrings: ['bla', 'asd', 'zzz', 'fgh'],
  computedStrings: Ember.computed('myStrings.[]', function() {
  	return this.get('myStrings')
      .map(aString => Ember.String.capitalize(aString));
  }),
  actions: {
    add() {
     this.get('myStrings').pushObject('testing');
     this.notifyPropertyChange('myStrings');
    }
  }
});

helpers.sort-helper.js

import Ember from 'ember';

export function sortHelper(params/*, hash*/) {
  return params[0].sort();
;
}

export default Ember.Helper.helper(sortHelper);

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<button {{action 'add'}}>Add</button>
<p>Normal property:</p>
{{#each (sort-helper myStrings) as |string|}}
  {{string}}
{{/each}}

<p>Computed property:</p>
{{#each (sort-helper computedStrings) as |string|}}
  {{string}}
{{/each}}
<br>
<br>

twiddle.json

{
  "version": "0.8.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.5.1",
    "ember-data": "2.5.2",
    "ember-template-compiler": "2.5.1"
  }
}