html safe string phantomjs issue

application.controller.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName:'Ember Twiddle'
});

application.template.hbs

<h1>Welcome to {{appName}}</h1>
<br>
{{auto-complete-emphasizer 'Batman and the batMobile' 'bat'}}
<br>
{{outlet}}
<br>
<br>

helpers.auto-complete-emphasizer.js

import Ember from 'ember';

// Inputs
// params[0] - Text to add emphasis parts too
// params[1] - searchText to use in emphasizing
// params[2] - (Optional) Emphasizing element i.e. i for <i>, defaults to <b>

export function autoCompleteEmphasizer(params) {
  if (params === undefined || params === null || params.length === 0) {
    return false;
  }

  var result = params[0];

  // If they only provide the string to search in then return it unaltered
  if (params.length === 1) {
    return result;
  }

  var searchText = params[1].toLowerCase().replace(/\(|\)/g, '');
  if (searchText.length === 0) {
    return result;
  }

  // Get search words and make sure search wordsare unique and non empty
  var searchWords = searchText.split(' ').uniq().reject(w => w === '');

  var emphasisElement = params[2] || 'b';

  // If any of the search words match the emphasis element then do that word first
  if (searchWords.contains(emphasisElement)) {
    searchWords.removeObject(emphasisElement);
    searchWords.insertAt(0, emphasisElement);
  }

  // Make sure result is html safe and contains nothing malicious
  result = Ember.Handlebars.Utils.escapeExpression(result);

  searchWords.forEach(w => result = result.replace(new RegExp('(^|)(' + w + ')(|$)','ig'), '$1<' + emphasisElement + '>$2</' + emphasisElement + '>$3'));

  // Make result as html safe as we know it contains no malicious html
  return Ember.String.htmlSafe(result);
}

export default Ember.Helper.helper(autoCompleteEmphasizer);

twiddle.json

{
  "version": "0.4.14",
  "EmberENV": {
    "FEATURES": {}
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.1.0/ember.debug.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/2.1.0/ember-data.js",
    "ember-template-compiler": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.1.0/ember-template-compiler.js"
  }
}