'filterBy' and undefined values

controllers.application.js

import Ember from 'ember';

var users = [
  Ember.Object.create({ name: "John", type: 'student' }),
  Ember.Object.create({ name: "Peter", type: 'teacher' }),
  undefined
];

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  john: Ember.Object.create({ name: "John", type: 'student' }),
  peter: Ember.Object.create({ name: "Peter", type: 'teacher' }),
  users: Ember.computed(function() {
  	return [
      john, peter, undefined
    ];
  },
  students: Ember.computed.filterBy('users', 'type', 'student')
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{#each students as |student|}}
  {{student.name}}
{{/each}}
<br>
<br>

twiddle.json

{
  "version": "0.11.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.10.2",
    "ember-data": "2.11.0",
    "ember-template-compiler": "2.10.2",
    "ember-testing": "2.10.2"
  },
  "addons": {}
}