Express.js error handling - working

server.js

var http = require('http');
var express = require('express');
var winston = require('winston');

var logger = ...
//setup Winston logger here, not really important

var app = express();
app.set('view engine', 'jade');
app.set('views', './views');

var mode = app.get('env');

var portNumber = 3000;

if(mode == 'production') {
	var oneDay = 24 * 60 * 60 * 1000;
	app.use(express.compress());
	app.use(express.static('./public', { maxAge: oneDay }));
}
else {
	app.use(express.static('./public'));
}

http.createServer(app).listen(portNumber, function() {
	console.log('Express app started on ' + portNumber + ' port in ' + mode + ' mode');
});

app.get('/hello', function(req, res) {
	res.send('Welcome!');
});

app.get('/starting', function(req, res) {
	res.render('start');
});

app.use(function(err, req, res, next) {
	logger.error('unknown error happened');
	res.status(500).send('something broke!');
});

app.get('/error', function(req, res, next) {
	somethingNonExistent(2016);
});