Added JSHint and JSXHint for linting the code.

assets/js/helpers/in_array.js

@@ -9,11 +9,10 @@ function in_array(needle, haystack) {
     for (var i = 0; i < haystack.length; i ++) {
         if (needle == haystack[i]) {
             return true;
-            break;
         }
     }
 
     return false;
 }
 
-export default in_array;
+module.exports = in_array;