NodeJs Session, Work in Postman but not in browser

Hello guys i have some problems with the express session where i cannot retrieve my session variable that i had stored previously. Below are parts of my codes that i had written.

server.js

let express = require('express'),
    path = require('path'),
    bodyParser = require('body-parser'),
    cors = require('cors'),
    config = require('./config/database'),
    expressSession = require('express-session'),
    uid = require('uid-safe'),
    db;

let app = express();

//Import Routes
let auth = require('./routes/auth'),
    chimerListing = require('./routes/chimer-listing'),
    brandListing = require('./routes/brand-listing');

//Specifies the port number
let port = process.env.PORT || 3000;
// let port = 3000;

// Express session
app.use(expressSession({
    secret: "asdasd",
    resave: true,
    saveUninitialized: false,
    cookie: {
        maxAge: 36000000,
        secure: false
    }
}));

//CORS Middleware
app.use(cors());

//Set Static Folder
var distDir = __dirname + "/dist/";
app.use(express.static(distDir));

//Body Parser Middleware
app.use(bodyParser.json());

//MongoDB
let MongoClient = require('mongodb').MongoClient;

MongoClient.connect(config.database, (err, database) => {
    if (err) return console.log(err)
    db = database;

    //Start the server only the connection to database is successful
    app.listen(port, () => {
        console.log('Server started on port' + port);
    });


});



//Make db accessbile to routers;
app.use(function(req, res, next) {
    req.db = db;
    res.set('Access-Control-Allow-Origin', '*');
    res.set('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE');
    res.set('Access-Control-Allow-Headers', 'Content-Type');
    next();
});

//Routes
app.use('/login', auth);
app.use('/user-listing', userListing);
app.use('/brand-listing', brandListing);

//Index Route
app.get('/', (req, res) => {
    res.send('Invalid Endpoint');
});

genuuid = function() {
    return uid.sync(18);
};

auth.js

let express = require('express'),
    router = express.Router(),
    db;

//Login Router for chimer
router.post('/chimer', (req, res, next) => {
    db = req.db;

    // let client = req.client;
    db.collection('chimeUser').find({
        Username: req.body.username,
        Password: req.body.password
    }).toArray().then(function(docs) {
        //If there is such user
        if (docs.length >= 1) {
            req.session.chimerId = docs[0]._id;
            console.log(req.session);
            req.session.save(function(err) {
                    // session saved
                    if (err)
                        console.log(err)
                    res.json({
                        success: true,
                        chimerId: docs[0]._id
                            //objects: docs
                    });
                })
        } else {
            res.json({
                success: false,
                //objects: docs
            })
        }
    });
});


//Login Router brand
router.post('/brand', (req, res, next) => {
    db = req.db;
    db.collection('brand').find({
        Username: req.body.username,
        Password: req.body.password
    }).toArray().then(function(docs) {
        req.session.brand = docs;

        console.log(req.session.brand);
        //If there is such user
        if (docs.length >= 1) {
            res.json({
                success: true,
                //objects: docs
            })
        } else {
            res.json({
                success: false,
                //objects: docs
            })
        }
        //db.close()
    });
});
});


module.exports = router;

user-listing.js

let express = require('express'),
    moment = require('moment'),
    router = express.Router(),
    // ObjectID = require('mongodb').ObjectID,
    db, client;

// let applyListing = require('../models/chimer-listing');

//Retrieve All Listing
router.get('/getAllListing', (req, res, next) => {
    db = req.db;
    console.log(req.session)
    db.collection('listing').find().toArray().then(function(listing) {
        //If there is any listing
        if (listing.length >= 1) {
            res.json({
                success: true,
                results: listing
            })
        } else {
            res.json({
                success: false,
            })
        }
        //db.close()
    });
});
module.exports = router;

So in my server.js, i have three routes file which are auth, user-listing and brand-listing.

Firstly, user will need to login onto the web application which is developed in angular2 and this will trigger the auth route. It will then check for the credentials whether does it exist in the database, if it exist i will then assign an ID to req.session.chimerId so that in other routes i will be able to use this chimerId.

Next after the user has logged in, they will then retrieve an item listing. The problem arises where i cant seem to retrieve the req.session.chimerId that i had previously saved. It will be undefined

NOTE : I tried this using Postman and the browser . In the Postman it works, i am able to retrieve back the req.session.chimerId whereas when i uses the angular2 application to hit the endpoints req.session.chimerId is always null

via TSL