Fuser::getIdByUserId

static function getIdByUserId($userId)
{
	$userId = (int)$userId;
	$id = static::getIdByFilter([
		'=USER_ID' => (int)$userId,
	]);
	if ($id === null)
	{
		$internalResult = static::createForUserId($userId);
		if ($internalResult->isSuccess())
		{
			$id = (int)$internalResult->getId();
		}
		unset($internalResult);
	}

	return $id === null ? false : $id;
}