toggleBy method

Future<bool> toggleBy(String fieldName)

Toggles single-field sorting between ascending and descending order.

If the current primary sort is not fieldName, sorting starts in ascending order.

Implementation

Future<bool> toggleBy(String fieldName) {
  if (!_canApplyViewOperation()) {
    return Future<bool>.value(false);
  }

  final normalizedFieldName = FdcFieldName.normalize(fieldName);
  final current = items;
  final isCurrentPrimarySort =
      current.isNotEmpty &&
      FdcFieldName.normalize(current.first.fieldName) == normalizedFieldName;

  return set(<FdcDataSetSort>[
    FdcDataSetSort(
      fieldName: fieldName,
      sortType: isCurrentPrimarySort
          ? current.first.sortType.toggled
          : FdcSortType.ascending,
    ),
  ]);
}