https://medium.com/node-js-indonesia/generate-dan-verify-jwt-di-expressjs-dengan-passportjs-928cddb2a995

index.js

const express = require('express');
const bodyParser = require('body-parser');
const passport = require('passport');
const jwt = require('jsonwebtoken');
const app = express();

app.use( bodyParser.urlencoded({ extended : false }) );

const router = express.Router();

//handling untuk route /login
router.post('/login', async (req, res) => {
  //data dummy (ganti dengan data dari database)
  const body = { email : 'email@gmail.com' };

  //Logic Login (ganti dengan logic kalian sendiri)
  if(req.body.email === body.email){
    //generate jwt menggunakan secret key 'node-js-indonesi'
    const token = jwt.sign({ user : body },'node-js-indonesia');
    //response hasil generate token
    return res.json({ token });
  }


  return res.json({
    error: {
      message: 'email salah'
    }
  })
});

app.use('/', router);

app.listen(4000, () => {
  console.log('Server started')
});