Grid::getVisibleColumnsIds

public function getVisibleColumnsIds(): array
{
	$visibleColumns = $this->getOptions()->GetVisibleColumns();
	if (empty($visibleColumns))
	{
		$visibleColumns = [];

		foreach ($this->getColumns() as $column)
		{
			if ($column->isDefault())
			{
				$visibleColumns[] = $column->getId();
			}
		}
	}

	return $visibleColumns;
}