code: function sort(viewChildren, orderBy) {
      if (orderBy) {
          viewChildren.sort(function (a, b) {
              var diff = orderBy === 'asc'
                  ? a.getValue() - b.getValue() : b.getValue() - a.getValue();
              return diff === 0
                  ? (orderBy === 'asc'
                      ? a.dataIndex - b.dataIndex : b.dataIndex - a.dataIndex
                  )
                  : diff;
          });
      }
      return viewChildren;
  }
docs: Sort