Implement cookie based authentication in Node JS with Passport - node.js

Question

Below is my server.js (app.js). I am using express with passport, for user authentication. But whenever I restart my node server user logsout.
I am very new to nodejs, I was wondering how I could implement a cookie based authentication. So that user does not log out even if the server starts. I'm sure theres some config change which I have not able to find.
// server.js
// set up ======================================================================
// get all the tools we need
var express = require('express');
var app = express();
var port = process.env.PORT || 80;
var mongoose = require('mongoose');
var passport = require('passport');
var flash = require('connect-flash');
var morgan = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var session = require('express-session');
var configDB = require('./config/database.js');
// configuration ===============================================================
mongoose.connect(configDB.url); // connect to our database
require('./config/passport')(passport); // pass passport for configuration
// set up our express application
app.use(morgan('dev')); // log every request to the console
app.use(cookieParser()); // read cookies (needed for auth)
app.use(bodyParser()); // get information from html forms
app.set('view engine', 'ejs'); // set up ejs for templating
// required for passport
app.use(session({ secret: 'yassers' })); // session secret
app.use(passport.initialize());
app.use(passport.session()); // persistent login sessions
app.use(flash()); // use connect-flash for flash messages stored in session
// routes ======================================================================
require('./app/routes.js')(app, passport); // load our routes and pass in our app and fully configured passport
// launch ======================================================================
app.listen(port);
console.log('The magic happens on port ' + port);

Answer 1

Its logout when you restart your start because its stored in MemoryStore(RAM). Use mongoStore to store your session mongodb. Try below code:
var session = require('express-session');
var MongoStore = require('connect-mongo')(session);
var mongoStore = new MongoStore({
url: 'your mongo db url'
});
app.use(session({
secret: 'your secret',
saveUninitialized: true, // don't create session until something stored
resave: false, //don't save session if unmodified
store: mongoStore,
cookie: {
domain: 'domain name',
maxAge: 1000 * 24 * 60
}
}));