title: RegExp inside ng-class raise error
body: <p>Why I have an error when I put Regexp inside ng-class?</p>
  
  <pre><code>&lt;a ng-class="{red:isActive(/test/)}"&gt;&lt;/a&gt;
  
  $scope.isActive = function(regexp){return true}
  </code></pre>
  
  <p>with string or num I havent error..</p>