index.js

const express = require("express");
const app = express();
const cors = require("cors");
const server = require("http").Server(app);
const io = require("socket.io")(server);
const { ExpressPeerServer } = require("peer");
const peerServer = ExpressPeerServer(server, {
  debug: true,
});

function randomNumber(length) {
  var text = "";
  var possible = "123456789";
  for (var i = 0; i < length; i++) {
    var sup = Math.floor(Math.random() * possible.length);
    text += i > 0 && sup == i ? "0" : possible.charAt(sup);
  }
  return text;
}

app.use(cors());
app.use("/peerjs", peerServer);

app.set("view engine", "ejs");
app.use(express.static("public"));

app.get("/", (req, res) => {
  res.redirect(`/${randomNumber(4)}`);
});

app.get("/:room", (req, res) => {
  res.render("room", { roomId: req.params.room });
});

io.on("connection", (socket) => {
  socket.on("join-room", (roomId, userId) => {
    socket.join(roomId);
    socket.to(roomId).broadcast.emit("user-connected", userId);
    socket.on("message", (message) => {
      io.to(roomId).emit("createMessage", message);
    });

    socket.on("disconnect", () => {
      socket.to(roomId).broadcast.emit("user-disconnected", userId);
    });
  });
});

server.listen(process.env.PORT || 3000);