server.js

const bodyParser = require("body-parser");
const { Socket } = require("dgram");
const ejs = require("ejs");

const express = require("express");
const app = express();

const http = require("http").createServer(app);
const io = require("socket.io")(http, { cors: { origin: "*" } });
const { v4: uuidV4 } = require("uuid");

app.set("view engine", "ejs");
app.use(bodyParser.urlencoded({ extended: true }));
app.use(express.static("public"));

app.get("/", (req, res) => {
    res.render("mainChat", { userName: users_name });
});

app.get("/login", (req, res) => {
    res.render("login");
});

app.post("/login", (req, res) => {
    const name = req.body.nameInp;
    // console.log(name);
    res.redirect("/mainChat");
});

const users = {};
const users_name = [];
let socketId = [];
let socketPair = {};
let peerId = {};

io.on("connection", (socket) => {
    console.log("Socket Array :" + socketId + "  Size :" + socketId.length);
    socket.on("idpasser", (id) => {
        // socket.broadcast.emit('user-connected',id);
        peerId[socket.id] = id;
        console.log(id);
    });
    function pairing() {
        if (socketId.length > 1) {
            socketId.splice(socketId.indexOf(socket.id), 1);
            console.log(
                "Socket Array after delete of socket.id :" +
                socketId +
                "  Size :" +
                socketId.length
            );
            let tempUser = socketId[Math.floor(Math.random() * socketId.length)];
            socketId.splice(socketId.indexOf(tempUser), 1);
            socketPair[socket.id] = tempUser;
            socketPair[tempUser] = socket.id;

            socket.to(tempUser).emit("user-connected", peerId[socket.id]);
            const stat = "you are now connected to a stranger";
            socket.to(socketPair[socket.id]).emit("status", stat);
            socket.emit("status", stat);
        }
    }
    socket.on("joinChat", (data) => {
        if (socketId.indexOf(socket.id) == -1) {
            console.log("Socket id getting from leave and join :" + data.socketId);
            socketId.push(socket.id);
        }
        pairing();
    });

    function left() {
        const stat = "Disconnected";
        socket.emit("status", stat);
        socket.to(socketPair[socket.id]).emit("status", stat);
        const tempData = socketPair[socket.id];
        delete socketPair[socket.id];
        delete socketPair[tempData];

        const messageDelete = "";
        socket.to(socketPair[socket.id]).emit("messageDelete", messageDelete);
    }

    socket.on("leave", (data) => {
        socket.to(socketPair[socket.id]).emit("disconnection", "Stranger");
        socket.to(socketPair[socket.id]).emit("user-disconnected", peerId[socket.id]);
        left();
    });

    socket.on("send", (message) => {
        socket
            .to(socketPair[socket.id])
            .emit("receive", { message: message, name: "Stranger" });
    });
    socket.on("disconnect", (message) => {
        socket.to(socketPair[socket.id]).emit("disconnection", "Stranger");
        socket
            .to(socketPair[socket.id])
            .emit("user-disconnected", peerId[socket.id]);
        left();
    });
});

http.listen(3000, () => {
    console.log("Server started at port 3000.");
});