ItemCategoryUserField::filter

public function filter(int $categoryId, array $fields): array
{
	if(!$this->isSupported())
	{
		return $fields;
	}

	$allowedUserFields = ItemCategoryUserFieldTable::getUserFieldsByEntityCategory($this->entityTypeId, $categoryId);
	if(empty($allowedUserFields))
	{
		return [];
	}

	return array_filter(
		$fields,
		static function($userFieldName) use ($allowedUserFields) {
			return in_array($userFieldName, $allowedUserFields);
		},
		ARRAY_FILTER_USE_KEY
	);
}