Linux Espruino - websocket send - 4 jsVars leaking each time

Here is the code (which won't run in isolation) as it requires files too...

var model = {
  setpoint : 66,
  timer : 60,
  temp: [50,50]
  //  counter : 3600
};

var event_cb = {
  timer : function (t) {
    model.counter = t * 60;
  }
};

event_cb.timer(model.timer);

function tick() {
  var d = new Date(model.counter * 1000);
  model.counterstr = d.toString().split(' ')[4];
  model.counter -= 1;
  model.free=process.memory().free;
  model.usage=process.memory().usage;

}

setInterval(tick, 1000);



function onPageRequest(req, res) {

  var a = url.parse(req.url, true);
  /**/
 // console.log(a);

  console.log({sckt:req.sckt});
  console.log(req.headers);
  //console.log(req.method);
   /**/
  var file = a.pathname;
  if (file == '/') {
    file = '/index.htm';
  }
  var headers = {};
  if (req.method == 'PUT')
    return put_file(req, res);
  var f;
  try {
    f = E.openFile('www' + file, "r");
  } catch (e) {
    // look for compressed
    try {
      f = E.openFile('www' + file + '.gz', "r");
      headers['Content-Encoding'] = 'gzip';
    } catch (e) {
      console.log('no file' + file);
    }
  }

  if (f !== undefined) {
    var mime = 'text/html';
    if (file.substr(-2) == 'js')
      mime = 'application/javascript';
    if (file.substr(-3) == 'css')
      mime = 'text/css';
    if (file.substr(-3) == 'ico')
      mime = 'image/vnd.microsoft.icon';

    headers['Content-Type'] = mime;

    res.writeHead(200, headers);
    console.log('started:' + file );
    f.pipe(res, {
      chunkSize : 512,
      end : false,
      complete : function () {
        console.log("Complete:" + file);
        f.close();
        res.end();
      }
    });

  } else {
    res.writeHead(404, {
      'Content-Type' : 'text/plain'
    });
    res.end("404: Page " + a.pathname + " not found");
  }
}

var server = require('ws').createServer(onPageRequest­);

var update_model=false;

server.on("websocket", function (ws) {
  ws.on('message', function (msg) { //console.log((msg));
    var data = JSON.parse(msg);
    console.log(data);
    if ( update_model ) {
    for (var o in data) {
      //console.log( o, data[o] );
      model[o] = data[o];
      if (event_cb.hasOwnProperty(o)) {
        event_cb[o](data[o]);
      }
    }
    }
  });
  function send_model() {
    var s=JSON.stringify(model);
    ws.send(s);
    s=null;
  }
  setInterval(send_model, 1000);
});

function start() {
  server.listen(8080);
}

start();