title: for (let .. of ) error in grunt build
body: <p>I have an Angular aplication and in some controller have the following code:</p>
  
  <pre><code>for (let subForm of $scope.info.subForms) {
      var index = $scope.data.fields.indexOf(subForm);
      $scope.data.subForms.push($scope.data.fields.splice (index + 1 , (subForm.data * subForm.filesLength)));
  };
  ......
  </code></pre>
  
  <p>when run my aplication using <code>grunt serve</code> the aplication run normal without errors but when generete the deploy code using the command <code>grunt build</code> get the following error: </p>
  
  <pre><code>Unexpected token name «subForm», expected punc «;». 
  Line 1410 in .tmp/concat/scripts/scripts.js
  Use --force to continue.
  </code></pre>
  
  <p>is a grunt error? I have <code>grunt v0.4.5</code>
  thanks for your help </p>
  
  <p><strong>EDIT</strong> </p>
  
  <p>In the following link <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...of" rel="nofollow">link</a> could see documentation about the syntax</p>