title: Error: JSON Parse error: Property name must be a string literal when using angular translate
body: <p>I use nodejs &amp; expressjs for my backend, Angular for my front-end. When using Angular translate in my site, the console shows this message:</p>
  
  <pre><code>Error: JSON Parse error: Property name must be a string literal
  parse@[native code]
  fromJson@http://localhost:3000/angular/angular.js:1321:19
  defaultHttpResponseTransform@http://localhost:3000/angular/angular.js:10393:24
  http://localhost:3000/angular/angular.js:10484:14
  forEach@http://localhost:3000/angular/angular.js:322:24
  transformData@http://localhost:3000/angular/angular.js:10483:10
  transformResponse@http://localhost:3000/angular/angular.js:11278:34
  processQueue@http://localhost:3000/angular/angular.js:15961:30
  http://localhost:3000/angular/angular.js:15977:39
  $eval@http://localhost:3000/angular/angular.js:17229:28
  $digest@http://localhost:3000/angular/angular.js:17045:36
  $apply@http://localhost:3000/angular/angular.js:17337:31
  done@http://localhost:3000/angular/angular.js:11572:53
  completeRequest@http://localhost:3000/angular/angular.js:11778:15
  requestLoaded@http://localhost:3000/angular/angular.js:11711:24
  </code></pre>
  
  <p>I am sure that all properties in JSON files are quoted.</p>
  
  <p>This is the locale files:</p>
  
  <pre><code>{
    "directives.language-select.Language": "Select Language",
    "views.video-modal.Download": "Download",
    "views.video-modal.Visit": "Visit",
    "views.video-modal.Copy": "Copy",
    "views.video-modal.Close": "Close",
  }
  </code></pre>
  
  <p>Strangely, when I only had</p>
  
  <pre><code>"directives.language-select.Language": "Select Language",
  </code></pre>
  
  <p>this line. The site worked perfectly. What causes this problem?</p>