Domain::getBitrix24Subdomain

static function getBitrix24Subdomain(string $domainName, ?string &$baseUrl = null): ?string
{
	$re = '/^([^.]+).(' . implode('|', self::B24_DOMAINS) . ')$/i';
	if (preg_match($re, $domainName, $matches))
	{
		$baseUrl = ".{$matches[2]}";
		return $matches[1];
	}

	return null;
}