Node.js: dispose/recreate HTTP server

I'm just playing around with Node.js for the first time. I have the standard base server.js file:

var server = require('http').createServer(function (req, res) {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('Hello World\n');
});
console.log('Server started and listening...');
server.listen(1337, '127.0.0.1');

Now, what I'd like to know how to do is, given server, how can I dispose of the instance and start up a new instance? For example, here's my naive pseudocode:

function launchServer() {
    var server = require('http').createServer(function (req, res) {
      res.writeHead(200, {'Content-Type': 'text/plain'});
      res.end('Hello World\n');
    });
    console.log('Server started and listening...');
    server.listen(1337, '127.0.0.1');
    return server;
}

var server = launchServer();

require('fs').watchFile('server.js', function(curr, prev) {
    console.log('Restarting server...');
    server = null;
    server = launchServer();
}); 

See what I'm trying to do here—reload the server.js file everytime I change it, as I play around and learn node.js?

I'm not necessarily interested in the "proper" way to do this or using a framework to do this; I'm interesting in learning the basics by doing things the hard, naive way first.