jwt.js

var jwt = require('jsonwebtoken'); // used to create, sign, and verify tokens
var config = require('../../config'); // get our config file
var User = require('./../user/User');

async function check(req) {

    var token = req.headers['authorization'];
    if (!token || !token.split(' ')[1])
        throw new Error('No token provided');
    var decoded = await jwt.verify(token.split(' ')[1], config.secret);
    req.username = decoded.username;
    var obj = await User.findOne({ username: req.username })
    if (!obj)
        throw new Error('Failed to find user');
    return true;
}



function verifyToken(req, res, next) {

    check(req).then((obj) => {
        next();
    }).catch((err) => {
        res.status(401).send({ auth: false, message: err.toString() });
    });

}

module.exports = verifyToken;

login.js

router.post('/login', function (req, res) {

    User.findOne({ username: req.body.username }, async function (err, user) {
        if (err) return res.status(500).send({ message: err.toString() });
        if (!user) return res.status(400).send({ message: 'Invalid Credentials' });

        if (user.password === req.body.password)
            var passwordIsValid = true;
        if (!passwordIsValid) return res.status(400).send({ auth: false, token: null, message: 'Invalid Credentials' });

        var token = jwt.sign({ username: user.username }, config.secret, {
            expiresIn: 86400 // expires in 24 hours
        });

        res.status(200).send({ auth: true, token: token });
    });

});