Concatenating words - Ember.js

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  fullName: Ember.computed(function() {
    let one = "Jason ";
    let two = undefined;
    let three = ' ';
    let four = "";
    let five = " Bourne ";
    let words = [one, two, three, four, five];
    console.log(words);
    
    // Removes blank strings and undefined; trims whitespaces and then joins
    words = words.filter(val => Ember.isPresent(val)).map(s => s.trim()).join(' ');
    console.log(words);
    return words;
  })
});

templates.application.hbs

<h1>{{appName}}</h1>
<br>
<br>
<pre style="background: pink; font-size: 1.5rem; display: inline; padding: 4px;">{{fullName}}</pre>
{{outlet}}
<br>
<br>

twiddle.json

{
  "version": "0.10.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.6.0",
    "ember-data": "2.6.1",
    "ember-template-compiler": "2.6.0"
  },
  "addons": {}
}