DataLoader::getAllowedPropertyId

private function getAllowedPropertyId($iblockId, array $propertyIds, $mode)
	{
		$list = null;
		switch ($mode)
		{
			case IblockModelPropertyFeature::FEATURE_ID_LIST_PAGE_SHOW:
				$list = IblockModelPropertyFeature::getListPageShowPropertyCodes($iblockId);
				break;
			case IblockModelPropertyFeature::FEATURE_ID_DETAIL_PAGE_SHOW:
				$list = IblockModelPropertyFeature::getDetailPageShowPropertyCodes($iblockId);
				break;
		}
		if (empty($list))
		{
			return [];
		}

		$result = array_intersect_key(
			array_fill_keys($propertyIds, true),
			array_fill_keys($list, true)
		);

		return (!empty($result) ? array_keys($result) : []);
	}