Had the same problem...im also new at javascript but i solved this with req.connection.remoteAddress; that gave me th IP address (but in ipv6 format ::ffff.192.168.0.101 ) and then .slice to remove the 7 first digits.

var ip = req.connection.remoteAddress;

if (ip.length < 15) 
{   
   ip = ip;
}
else
{
   var nyIP = ip.slice(7);
   ip = nyIP;
}

如果使用快递...

req.ip

我一直在寻找，然后就像等待，我正在使用快递。咄。