ImportService::isAdmin

static function isAdmin(int $userId): bool
{
	global $USER;
	if (Loader::includeModule('bitrix24'))
	{
		if (
			$USER instanceof CUser
			&& $USER->isAuthorized()
			&& $USER->isAdmin()
			&& (int)$USER->getId() === $userId
		)
		{
			return true;
		}

		return CBitrix24::isPortalAdmin($userId);
	}

	if (
		$USER instanceof CUser
		&& $USER->isAuthorized()
		&& (int)$USER->getId() === $userId
	)
	{
		return $USER->isAdmin();
	}

	$result = false;
	$groups = UserTable::getUserGroupIds($userId);
	foreach ($groups as $groupId)
	{
		if ((int)$groupId === 1)
		{
			$result = true;
			break;
		}
	}

	return $result;
}