code: function (item, array, fnEqual) {
          
          if (Arrays.indexOf(item, array, null, fnEqual) < 0) {
              array.push(item);
              return true;
          }
          else
              return false;
      }
docs: Appends <code>item</code> to <code>array</code>,
  but only if it isn't already in the array.
  
  Note: this function may modify <code>array</code>.
  
  @param item {Object}
  @param array {Array}
  @param fnEqual {Function} Optional.
  @return {Boolean} Whether <code>array</code> was modified.