Simple way to sign in with github for oAuth in Node/Express

index.js

const express = require("express")
const app = express()
var passport = require("passport")
var session = require("express-session")
var GitHubStrategy = require("passport-github2").Strategy

const GITHUB_CLIENT_ID = "your-client-id-here" // or get from process.env.GITHUB_CLIENT_ID
const GITHUB_CLIENT_SECRET = "your-client-secret-here" // or get from process.env.GITHUB_CLIENT_SECRET
const GITHUB_CALLBACK_URL = "http://localhost:5000/auth/github/callback" // or get from process.env.GITHUB_CALLBACK_URL

function ensureAuthenticated(req, res, next) {
  if (req.isAuthenticated()) {
    return next()
  }
  res.redirect("/login")
}

passport.serializeUser(function(user, done) {
  done(null, user)
})

passport.deserializeUser(function(obj, done) {
  done(null, obj)
})

passport.use(
  new GitHubStrategy(
    {
      clientID: GITHUB_CLIENT_ID,
      clientSecret: GITHUB_CLIENT_SECRET,
      callbackURL: GITHUB_CALLBACK_URL
    },
    function(accessToken, refreshToken, profile, done) {
      // asynchronous verification, for effect...
      console.log({ accessToken, refreshToken, profile })
      
      // an example of how you might save a user
      // new User({ username: profile.username }).fetch().then(user => {
      //   if (!user) {
      //     user = User.forge({ username: profile.username })
      //   }
      // 
      //   user.save({ profile: profile, access_token: accessToken }).then(() => {
      //     return done(null, user)
      //   })
      // })
    }
  )
)
app.use(
  session({ secret: "keyboard cat", resave: false, saveUninitialized: false })
)
app.use(passport.initialize())
app.use(passport.session())

app.get("/", (req, res) => {
  res.send("<a href='/secret'>Access Secret Area</a>")
})

app.get("/login", (req, res) => {
  res.send("<a href='/auth/github'>Sign in With GitHub</a>")
})

app.get("/secret", ensureAuthenticated, (req, res) => {
  res.send(`<h2>yo ${req.user}</h2>`)
})

app.get(
  "/auth/github",
  passport.authenticate("github", { scope: ["repo:status"] }), /// Note the scope here
  function(req, res) { }
)

app.get(
  "/auth/github/callback",
  passport.authenticate("github", { failureRedirect: "/login" }),
  function(req, res) {
    res.redirect("/")
  }
)

const port = process.env.PORT || 5000
app.listen(port, () => console.log(`listening on port ${port}`))