How to make my nodejs program robust to error conditions?

So I have this nodejs proxy:

var http      = require('http');
var httpProxy = require('http-proxy');

var routes = [
  'http://127.0.0.1:80',
  'http://127.0.0.1:8001'
];

var proxy = new httpProxy.createProxyServer({});

var proxyServer = http.createServer(function (req, res) {
    var route=0;
    var split1=req.url.split('/');
    if (split1.length>0) {
        if(split1[1]=="socket.io"){
            route=1;
        }
    }

    proxy.web(req, res, {target: routes[route]});
});
proxyServer.on('upgrade', function (req, socket, head) {
    proxy.ws(req, socket, head, {target: routes[1]});
});
proxyServer.listen(80,"x.x.x.x");

It listens on port 80 and analyses each request. If it's a normal HTTP request, it gets directed to 127.0.0.1:80. If it's a websocket request (socket.io variety), it gets directed to 127.0.0.1:8001.

Everything seems to work fine.

But I don't have any exception handling.

Can anyone suggest any tips and/or things to watch out for?

Please bear in mind that I'm not a networking expert, nor do I have much experience with node.js. I guess experienced people can spot the big holes in what I'm doing very quickly, hence me posting here.