Nodejs Express code to redirect mobile user agets

detect-mobile-browser.js

var express = require('express'),
  app = express();
app.listen(80);
app.get('/', function(req, res){
    var ua = req.header('user-agent');
    // Check the user-agent string to identyfy the device. 
    if(/mobile|iphone|ipod|android|blackberry|opera|mini|windows\sce|palm|smartphone|iemobile|ipad|android|android 3.0|xoom|sch-i800|playbook|tablet|kindle/i.test(ua)) {
        res.sendfile(__dirname + '/mobile.html');
    } else {
        res.sendfile(__dirname + '/index.html');
    }
});