In this tutorial, we will be building a chat app using Next.js, a popular framework for building server-rendered React applications. This chat app will allow users to send messages to each other in real-time, and will also feature a list of online users.

Before we get started, make sure you have the following tools installed on your machine:

• Node.js

• npm (which comes with Node.js)

• Next.js

Once you have these tools installed, let's create a new Next.js project by running the following command in your terminal:

npx create-next-app my-app

This will create a new directory called my-app with the basic structure of a Next.js app.

Next, let's install the dependencies we will be using for our chat app. We will be using Socket.io for real-time communication, as well as Express for our server. Run the following command to install these dependencies:

npm install socket.io express

Now that we have all the necessary dependencies, let's start building our chat app.

First, we need to create a server that will handle the real-time communication between clients. In the root of your project, create a file called server.js and add the following code:

const express = require('express');
const http = require('http');
const socketIO = require('socket.io');

const app = express();
const server = http.createServer(app);
const io = socketIO(server);

server.listen(3000, () => {
  console.log('Server listening on port 3000');
});

This code creates an Express server and sets up Socket.io to work with it. The server is then started on port 3000.

Next, let's create a page for our chat app. In the pages directory of your Next.js project, create a file called chat.js. This will be the entry point for our chat app.

In chat.js, add the following code:

import { useEffect } from 'react';
import io from 'socket.io-client';

const Chat = () => {
  useEffect(() => {
    const socket = io('http://localhost:3000');
  }, []);

  return (
    <div>
      <h1>Chat App</h1>
    </div>
  );
};

export default Chat;

This code imports the useEffect hook from React and sets up a connection to our Socket.io server.

Now that we have a basic setup for our chat app, let's add some functionality. We will start by displaying a list of online users. To do this, we will need to keep track of the users that are connected to our Socket.io server.

In server.js, add the following code:

let users = [];

io.on('connection', (socket) => {
  console.log('New user connected');

  // Add new user to the list of users
  users.push(socket.id);
  io.emit('updateUsers', users);

  // Remove user from the list of users when they disconnect
  socket.on('disconnect', () => {
    console.log('User disconnected

We will continue with building the chat app in the next part.

Thanks.