setuppassport.js

var passport = require('passport');
var LocalStrategy = require('passport-local').Strategy;

var User = require('./models/user');

passport.use('login', new LocalStrategy(
    function(username, password, done) {
        User.findOne({ username: username }, function(err, user) {
            if (err) { return done(err); }
            if (!user) {
                return done(null, false,
                    { message: "No such username!" });
            }
            user.checkPassword(password, function(err, isMatch) {
                if (err) { return done(err); }
                if (isMatch) {
                    return done(null, user);
                } else {
                    return done(null, false,
                        { message: "Invalid password." });
                }
            });
        });
    }
));

module.exports = function() {
    passport.serializeUser(function(user, done) {
        done(null, user._id);
    });

    passport.deserializeUser(function(id, done) {
        User.findById(id, function(err, user) {
            done(err, user);
        });
    });
};