ListStrategy::getShowedFieldsNames

protected function getShowedFieldsNames(Collection $fieldsCollection): array
{
	$options = $this->getCurrentOptions();

	if ($options['columns'] === '' || $options['columns'] === null)
	{
		$visibleFieldsNames = [];
		foreach ($fieldsCollection as $field)
		{
			$showUserFieldInList = ($field->isUserField() && $field->getUserField()['SHOW_IN_LIST'] === 'Y');
			if (
				$showUserFieldInList
				|| in_array($field->getName(), self::DEFAULT_SHOW_FIELD_NAMES)
			)
			{
				$visibleFieldsNames[] = $field->getName();
			}
		}
	}
	else
	{
		$visibleFieldsNames = explode(',', $options['columns']);
	}

	$this->addFieldAliases($visibleFieldsNames);

	return $visibleFieldsNames;
}