server.js

const express=require('express')
const app =express()

var http = require('http').createServer(app);
var io = require('socket.io')(http);

var path=require('path')
var map={}
var revmap={}


function generateUIN(){
    return Math.floor(Math.random()*10)
}

function myUIN(){
    let uin= generateUIN().toString()+generateUIN().toString()+
           generateUIN().toString()+generateUIN().toString()+
           generateUIN().toString()+generateUIN().toString();       
    return uin;       
}

io.on('connection',(socket)=>{
    console.log('User connected');
    let uin=myUIN()
    map[socket.id]=uin;
    revmap[uin]=socket.id;
    socket.emit('uin',uin)
    socket.on('message',(message)=>{
        console.log(message)
        io.emit('forward',message)
    })
})

app.use(express.json())
app.use(express.urlencoded({
    extended:true
}))

app.use('/',express.static(path.join(__dirname,'public')))

app.get('/',(req,res)=>{
    res.sendFile(__dirname+'/index.html')
})

//app.listen(3000||process.env.PORT)
http.listen(4000, function(){
    console.log('listening on *:4000');
  });