Gist for article for jwt implementation.

jwt-implement.js

const jwt = require('jsonwebtoken');
const app = require('express')();
const passport = require('passport');
const LocalStrategy = require('passport-local').Stratergy;
const JwtStrategy = require('passport-jwt').Strategy;
const ExtractJwt = require('passport-jwt').ExtractJwt;

// Use Local Startergy for authenticating user 
passport.use(new LocalStrategy(
  function(username, password, done) {
    User.findOne({ username: username }, function (err, user) {
      if (err) { return done(err); }
      if (!user) { return done(null, false); }
      if (!user.verifyPassword(password)) {
        return done(null, false);
      }
      return done(null, user);
    });
  }
));
// Apply passport authentication for getting user payload 
app.post('/login', (req, res, next) => {
  passport.authenticate('local', (err, userData) => {
      if (!userData || err) {
        return res.status(404).json({
          msg: 'Account not available. Please Sign Up.',
        });
      }
      req.logIn(user, (error) => {
        if (error) return next(error);
        return res.json({
          token: jwt.sign({user: userData}, 'secret'),
        });
      });
    })(req, res, next);
});

// Using passport-jwt stratergy
passport.use(new JwtStrategy({
  jwtFromRequest : ExtractJwt.fromAuthHeaderAsBearerToken(),
  secretOrKey :'secret',
  },
  function(jwt_payload, done) {
    User.findOne({_id: jwt_payload._id}, function(err, user) {
      if (err || !user) {
        return done(err, false);
      }
      if (user) {
         return done(null, user);
      }
    });
}));


// Calling passport authenticate method jwt authentication 
app.get('/user', passport.authenticate('jwt', { session: false }), (req, res) => {
  res.json({
    user: req.user
  });
});


// Request from front-end 
fetch('/user', {
  method: GET,
  headers: {
    'Authorization' : `Bearer ${localStorage.getItem('jwt')}`,
  },
});