.js

var express = require('express')
var session = require('express-session')
const mustacheExpress = require('mustache-express')
const bodyParser = require('body-parser')
var app = express()

app.engine('mustache',mustacheExpress())
app.use(bodyParser.urlencoded({extended :true}))

app.set('views','./views')
app.set('view engine','mustache')

// setup middleware to use sessions
app.use(session({
  secret : 'cat'
}))

app.get('/logout',function(req,res){
  req.session.destroy()
  res.redirect("login")
})

app.get('/admin',function(req,res){

  if(req.session.username) {
    res.render("admin")
  } else {
    res.render("error")
  }

})

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

  console.log(req.body.username)
  let username = req.body.username
  req.session.username = username
  res.end()

})

app.get('/login',function(req,res){
  res.render('login')
})


app.listen(3000,function(){
  console.log("app is running on port 3000")
})