Demo for Passport.js authentication in a Node.js Express application

package.json

{
  "name": "securehelloworld",
  "version": "1.0.0",
  "description": "",
  "main": "server.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "express": "^4.13.3",
    "express-session": "^1.11.3",
    "passport": "^0.3.0",
    "passport-github": "^1.0.0"
  }
}

server.js

var express = require('express');
var app = express();
var passport = require('passport');
var GithubStrategy = require('passport-github').Strategy;

passport.use(new GithubStrategy({
    clientID: "YOUR CLIENT ID",
    clientSecret: "YOUR CLIENT SECRET",
    callbackURL: "http://localhost:30000/auth/github/callback"
  },
  function(accessToken, refreshToken, profile, done) {
    // placeholder for translating profile into your own custom user object.
    // for now we will just use the profile object returned by GitHub
    return done(null, profile);
  }
));

// Express and Passport Session
var session = require('express-session');
app.use(session({secret: "enter custom sessions secret here"}));
app.use(passport.initialize());
app.use(passport.session());

passport.serializeUser(function(user, done) {
  // placeholder for custom user serialization
  // null is for errors
  done(null, user);
});

passport.deserializeUser(function(user, done) {
  // placeholder for custom user deserialization.
  // maybe you are getoing to get the user from mongo by id?
  // null is for errors
  done(null, user);
});

// we will call this to start the GitHub Login process
app.get('/auth/github', passport.authenticate('github'));

// GitHub will call this URL
app.get('/auth/github/callback',
  passport.authenticate('github', { failureRedirect: '/' }),
  function(req, res) {
    res.redirect('/');
  });

app.get('/', function (req, res) {
  var html = "<ul>\
    <li><a href='/auth/github'>GitHub</a></li>\
    <li><a href='/logout'>logout</a></li>\
  </ul>";

  // dump the user for debugging
  if (req.isAuthenticated()) {
    html += "<p>authenticated as user:</p>"
    html += "<pre>" + JSON.stringify(req.user, null, 4) + "</pre>";
  }

  res.send(html);
});

app.get('/logout', function(req, res){
  console.log('logging out');
  req.logout();
  res.redirect('/');
});

// Simple route middleware to ensure user is authenticated.
//  Use this route middleware on any resource that needs to be protected.  If
//  the request is authenticated (typically via a persistent login session),
//  the request will proceed.  Otherwise, the user will be redirected to the
//  login page.
function ensureAuthenticated(req, res, next) {
  if (req.isAuthenticated()) { return next(); }
  res.redirect('/')
}

app.get('/protected', ensureAuthenticated, function(req, res) {
  res.send("acess granted");
});



var server = app.listen(30000, function () {
  console.log('Example app listening at http://%s:%s',
    server.address().address, server.address().port);
});

could you solve the issue? i am getting the same error

Line 42 should be:
passport.authenticate('github', { failureRedirect: '/auth/github' }),
(It keeps on redirecting back to '/' ad infinitum otherwise)