ExpressJS Oauth2 Google Strategy JWT

require('dotenv').config()
const cors = require('cors')
const bodyParser = require('body-parser')
const express = require('express')
const expressJwt = require('express-jwt')
const cookieSession = require('cookie-session')
const jwt = require('jsonwebtoken')
const passport = require('passport')
const GoogleStrategy = require('passport-google-oauth20').Strategy
const jwtSecret = Buffer.from('Zn8Q5tyZ/G1MHltc4F/gTkVJMlrbKiZt', 'base64')
var knex = require('knex')({
  client: 'pg',
  connection: process.env.TWIGGY_DB
})

passport.serializeUser((user, done) => {
  done(null, user)
})

passport.deserializeUser((user, done) => {
  knex('users')
  .where({email: user.email})
  .first('email')
  .returning(['id', 'email']).then((user) => {
    done(null, user)
  })
})

// Setup Passport
passport.use(
  new GoogleStrategy({
    clientID: process.env.GOOGLE_CLIENT_ID,
    clientSecret: process.env.GOOGLE_CLIENT_SECRET,
    callbackURL: '/redirect'
  }, (accessToken, refreshToken, profile, done) => {
    const email = profile.emails[0].value
    knex('users').where({email: email}).then((user) => {
      // !currentUser, pass it on
      if(user){
        console.log('currentUser is: ', user[0]);
        done(null, user[0]);
      } else {
        // !currentUser, create user in our db
        knex('users')
        .insert({
          email: email,
        })
        .returning(['id', 'email'])
        .then((user) => {
          console.log('newUser: ', user[0])
          done(null, user[0])
        })
      }
    })
  })
)

// Setup app
const app = express()
app.use(cors(), bodyParser.json(), expressJwt({
  secret: jwtSecret,
  credentialsRequired: false
}))
// set up session cookies
app.use(cookieSession({
  // Lasts one day
  maxAge: 24 * 60 * 60 * 1000,
  // @todo needs a better cookieKey
  keys: [process.env.SESSION_COOKIE_KEY]
}))

app.use(passport.initialize())
app.use(passport.session())

app.get('/', (req, res) => {
  res.send('oauth2')
})

app.get('/oauth2', passport.authenticate('google', {
  scope: ['profile', 'email'],
  hostedDomain: process.env.HOSTED_DOMAIN
}))

app.get('/redirect', passport.authenticate('google'), (req, res) => {
  const token = jwt.sign({sub: req.user.email}, jwtSecret)
  res.redirect(`${process.env.REDIRECT_URL}?token=${token}`)
})
app.get('/logout', (req, res) => {
  req.logout()
  res.redirect('/')
})

app.listen(3000, () => {
  console.log('app now listening for requests on port 3000')
})