Agent::getSubFolders

static function getSubFolders(int $folderId): array
{
	$folders = [];
	$res = Folder::getList([
		'select' => [
			'ID'
		],
		'filter' => [
			'PARENT_ID' => $folderId
		]
	]);
	while ($row = $res->fetch())
	{
		$folders[] = $row['ID'];
		$folders = array_merge($folders, self::getSubFolders($row['ID']));
	}
	return $folders;
}