code: function (elt1, elt2) {
          if (elt1.sortKey == elt2.sortKey) {
              return 0;
          }
          return (elt1.sortKey > elt2.sortKey ? 1 : -1);
      }
docs: Sorting function by ascending sortKey. Function given as a parameter to the Array.sort JavaScript function for
  sorting. It compares two elements and return a value telling which one should be put before the other.
  @param {aria.templates.ViewCfgBeans:Item} elt1
  @param {aria.templates.ViewCfgBeans:Item} elt2
  @return {Integer} -1 if elt1.sortKey &lt; elt2.sortKey, 0 if elt1.sortKey == elt2.sortKey, 1 if elt1.sortKey &gt;
  elt2.sortKey
  @private