Element::getOrder

private function getOrder($availableFieldsIdForSort)
{
	$order = [];

	if (is_array($this->params["ELEMENT_ORDER"]))
	{

		$orderList = ["nulls,asc", "asc,nulls", "nulls,desc", "desc,nulls", "asc", "desc"];
		foreach ($this->params["ELEMENT_ORDER"] as $fieldId => $orderParam)
		{
			$orderParam = mb_strtolower($orderParam);
			if (!in_array($orderParam, $orderList) || !in_array($fieldId, $availableFieldsIdForSort))
			{
				continue;
			}
			$order[$fieldId] = $orderParam;
		}
	}

	if (empty($order))
	{
		$order = ["ID" => "asc"];
	}

	return $order;
}