apply<T extends DataGridRow> method

@override DataGridState<T>? apply<T extends DataGridRow>(EventContext<T> context)

Apply this event's transformation to the state. Returns the new state, or null if no state change should occur. Can return a Future for async operations.

Implementation

@override
DataGridState<T>? apply<T extends DataGridRow>(EventContext<T> context) {
  final cellId = '${rowId}_$columnId';
  final current = context.state.selection.focusedCells;

  if (current.isEmpty) {
    // No anchor yet — treat like a plain focus
    return context.state.copyWith(
      selection: context.state.selection.copyWith(focusedCells: [cellId]),
    );
  }

  if (current.last == cellId) return null; // already active, no-op

  if (current.contains(cellId)) return null; // already in path, no-op

  return context.state.copyWith(
    selection: context.state.selection.copyWith(
      focusedCells: [...current, cellId],
    ),
  );
}