CIntranetRestService::prepareSort

static function prepareSort($query): array
{
	$query = array_change_key_case($query, CASE_UPPER);
	$sort = ['LEFT_MARGIN' => 'ASC'];

	if (isset($query['SORT']) && is_string($query['SORT']))
	{
		$sortField = mb_strtoupper($query['SORT']);
		if (in_array($sortField, self::$arAllowedDepartmentFields))
		{
			$order = isset($query['ORDER']) && is_string($query['ORDER']) ? mb_strtoupper($query['ORDER']) : '';
			if ($order != 'DESC')
				$order = 'ASC';

			$sort = [$sortField => $order];
		}
	}
	return $sort;
}