1v91 HTTP server callback called twice

I have just got started using Espruino, it looks great, but I have come across a few issues. I don't know if it's my fault, but I have found that when I use the built in HTTP server the callback function is called twice. Once with the query parameters, and once (second time) with them nulled out. This

I am using using a compiler to generate my JS, so it's slightly awkward but still readable. Here is the callback used by wifi.connect()

 var onConnected = function onConnected(err) {
    if (err == null) {
      console.log("IP: " + wifi.getIP().ip);

      var http = require("http");

      var callback = function callback(request, response) {
        var query = void 0;
        var matchValue = url.parse(request.url, true).query;

        if (matchValue == null) {
          query = null;
        } else {
          query = matchValue;
        }

        response.writeHead(200);
        response.write("<a href=\"?led=1\">on</a><br/><a href=\"?led=0\">off</a>");
        response.end("sup dawg?");
        console.log("Callback called");

        if (query != null) {
          var matchValue_1 = query.led;

          if (matchValue_1 === "1") {
            digitalWrite(outPutPin, 1);
          } else {
            digitalWrite(outPutPin, 0);
          }
        }
      };

      var server = http.createServer(callback);
      server.listen(80);
    } else {
      console.log("Error: " + err);
    }
  };    

log output from hitting the page once:

=undefined
IP: 192.168.1.102
Callback called
Callback called

The work around I'm using is just to only set the LEDs if the query is not null. What might be going wrong?

Thanks

Maybe you could dump the contents of the request object at the same time? You usually get two requests from a browser - one for the requested page, and one for the favicon.

That sounds like a good explanation. I'm so used to using a router I overlooked that it would request a favicon too.

Thanks