code: function itemChanged(slot) {
                      var itemNew = slot.itemNew;
  
                      if (!itemNew) {
                          return false;
                      }
  
                      var item = slot.item;
  
                      for (var property in item) {
                          switch (property) {
                              case "data":
                                  // This is handled below
                                  break;
  
                              default:
                                  if (item[property] !== itemNew[property]) {
                                      return true;
                                  }
                                  break;
                          }
                      }
  
                      return (
                          listDataAdapter.compareByIdentity ?
                              item.data !== itemNew.data :
                              slot.signature !== itemSignature(itemNew)
                      );
                  }
docs: Fetch Result Processing