index.js

//node server which will handle socket io connections
const io = require('socket.io')(8000)

const users ={};

io.on('connection',socket =>{
    //if any new user joins, let other users connected to the server know!
    socket.on('new-user-joined',name =>{
      
      users[socket.id] = name;
      socket.broadcast.emit('user-joined', name);  
    });
 //if someone send a message then broadcast it to other people
    socket.on('send',message=>{
        socket.broadcast.emit('recieve', {message:message, name:users[socket.id]})
    });
  //if someone leaves the chat, let other know  
    socket.on('disconnect', message =>{
      socket.broadcast.emit('right', user[socket.id]);
      delete users[socket.id];
    });
})