server.js

const io = require('socket.io')();
const os = require('os')

let id = 0;
let jots = [];
let ghostJots = [];

io.on('connection', (socket) => {
  socket.emit('connected')

  jots.forEach((jotData) => {
    socket.emit('new jot', jotData);
  })
  console.log('A user connected')
  socket.on('disconnect', () => { console.log('A user disconnected')})

  socket.on('new jot', (jotData) => { 
    jotData.id = id++;
    ghostJots.push(jotData);
    socket.emit('new jot', jotData)
   })

   socket.on('jot moved', (moveData) => {
     let beforeLength = ghostJots.length
     ghostJots = ghostJots.filter((jot) => jot.id !== moveData.id)
     if (ghostJots.length !== beforeLength) {
       io.emit("new jot", moveData);
       jots.push(moveData);
     }

     // Update the jot in our list
     for (let jot of jots) {
       if (jot.id === moveData.id) { 
         jot.position = moveData.position;
         break;
       }
     }
     // Notify clients
     io.emit('jot moved', moveData);
   })

   socket.on('delete jot', (jotData) => {
     jots = jots.filter(jot => jot.id !== jotData.id)
     io.emit('delete jot', jotData);
   });

   socket.on("delete all", () => {
     for (let jot of jots) {
       io.emit("delete jot", { id: jot.id });
     }
     jots = [];
   });

   socket.on("updateVotes", (voteData) => {
     for (let jot of jots) {
       if (jot.id === voteData.id) { 
         jot.votes = voteData.votes;
         break;
       }
     }
     io.emit("updateVotes", voteData)
   })

   socket.on("lock jot", ({id}) => {
     socket.broadcast.emit("lock jot", {id})
   })
});

let networkInterfaces = os.networkInterfaces();
console.log('Addresses: ')
for (const iface in networkInterfaces) {
  for (const thing of networkInterfaces[iface]) {
    console.log(thing.address);
  }
}

const port = 8000;
io.listen(port);
console.log('listening on port ', port);