DEV Community

Cover image for Building a chat app with Socket.io and React 🚀
novu profile image Nevo David
Nevo David Subscriber for novu

Posted on • Updated on • Originally published at novu.co

Building a chat app with Socket.io and React 🚀

#react #node #javascript #programming

Like this article?
Follow me on X:
https://x.com/nevodavid

What is this article about?

We have all encountered chat over the web, that can be Facebook, Instagram, Whatsapp and the list goes on.
Just to give a bit of context, you send a message to a person or a group, they see the message and reply back. Simple yet complex.

To develop a chat app you would need to be aware of new messages as soon as they arrive.
Usually, to get information from the server you need send an HTTP request. With websockets, the server lets you know when there is new information without asking it.

In this article, we'll leverage the real-time communication provided by Socket.io to create an open chat application that allows users to send and receive messages from several users on the application. You will also learn how to detect the users who are online and when a user is typing.

💡 To read this article you'll need to have a basic knowledge of React.js and Node.js to comprehend this article.

Chat

What is Socket.io?

Socket.io is a popular JavaScript library that allows us to create real-time, bi-directional communication between web browsers and a Node.js server. It is a highly performant and reliable library optimized to process a large volume of data with minimal delay. It follows the WebSocket protocol and provides better functionalities, such as fallback to HTTP long-polling or automatic reconnection, which enables us to build efficient chat and real-time applications.

Novu - the first open-source notification infrastructure

Just a quick background about us. Novu is the first open-source notification infrastructure. We basically help to manage all the product notifications. It can be In-App (the bell icon like you have in Facebook - Websockets), Emails, SMSs and so on.
I would be super happy if you could give us a star! And let me also know in the comments ❤️
https://github.com/novuhq/novu

Novu

How to connect a React.js app to Node.js via Socket.io

In this section, we'll set up the project environment for our chat application. You'll also learn how to add Socket.io to a React and Node.js application and connect both development servers for real-time communication via Socket.io.

Create the project folder containing two sub-folders named client and server.



mkdir chat-app
cd chat-app
mkdir client server
Enter fullscreen mode Exit fullscreen mode

Navigate into the client folder via your terminal and create a new React.js project.



cd client
npx create-react-app ./
Enter fullscreen mode Exit fullscreen mode

Install Socket.io client API and React Router. React Router is a JavaScript library that enables us to navigate between pages in a React application.



npm install socket.io-client react-router-dom
Enter fullscreen mode Exit fullscreen mode

Delete the redundant files such as the logo and the test files from the React app, and update the App.js file to display Hello World as below.



function App() {
  return (
    <div>
      <p>Hello World!</p>
    </div>
  );
}
Enter fullscreen mode Exit fullscreen mode

Next, navigate into the server folder and create a package.json file.



cd server
npm init -y
Enter fullscreen mode Exit fullscreen mode

Install Express.js, CORS, Nodemon, and Socket.io Server API.

Express.js is a fast, minimalist framework that provides several features for building web applications in Node.js. CORS is a Node.js package that allows communication between different domains.

Nodemon is a Node.js tool that automatically restarts the server after detecting file changes, and Socket.io allows us to configure a real-time connection on the server.



npm install express cors nodemon socket.io
Enter fullscreen mode Exit fullscreen mode

Create an index.js file - the entry point to the web server.



touch index.js
Enter fullscreen mode Exit fullscreen mode

Set up a simple Node.js server using Express.js. The code snippet below returns a JSON object when you visit the http://localhost:4000/api in your browser.



//index.js
const express = require('express');
const app = express();
const PORT = 4000;

app.get('/api', (req, res) => {
  res.json({
    message: 'Hello world',
  });
});

app.listen(PORT, () => {
  console.log(`Server listening on ${PORT}`);
});
Enter fullscreen mode Exit fullscreen mode

Import the HTTP and the CORS library to allow data transfer between the client and the server domains.



const express = require('express');
const app = express();
const PORT = 4000;

//New imports
const http = require('http').Server(app);
const cors = require('cors');

app.use(cors());

app.get('/api', (req, res) => {
  res.json({
    message: 'Hello world',
  });
});

http.listen(PORT, () => {
  console.log(`Server listening on ${PORT}`);
});
Enter fullscreen mode Exit fullscreen mode

Next, add Socket.io to the project to create a real-time connection. Before the app.get() block, copy the code below.



//New imports
.....
const socketIO = require('socket.io')(http, {
    cors: {
        origin: "http://localhost:3000"
    }
});

//Add this before the app.get() block
socketIO.on('connection', (socket) => {
    console.log(`⚡: ${socket.id} user just connected!`);
    socket.on('disconnect', () => {
      console.log('🔥: A user disconnected');
    });
});
Enter fullscreen mode Exit fullscreen mode

From the code snippet above, the socket.io("connection") function establishes a connection with the React app, then creates a unique ID for each socket and logs the ID to the console whenever a user visits the web page.

When you refresh or close the web page, the socket fires the disconnect event showing that a user has disconnected from the socket.

Next, configure Nodemon by adding the start command to the list of the scripts in the package.json file. The code snippet below starts the server using Nodemon.



//In server/package.json

"scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "nodemon index.js"
  },
Enter fullscreen mode Exit fullscreen mode

You can now run the server with Nodemon by using the command below.



npm start
Enter fullscreen mode Exit fullscreen mode

Open the App.js file in the client folder and connect the React app to the Socket.io server.



import socketIO from 'socket.io-client';
const socket = socketIO.connect('http://localhost:4000');

function App() {
  return (
    <div>
      <p>Hello World!</p>
    </div>
  );
}
Enter fullscreen mode Exit fullscreen mode

Start the React.js server.



npm start
Enter fullscreen mode Exit fullscreen mode

Check the terminal where the server is running; the ID of the React.js client appears in the terminal.

Congratulations 🥂 , the React app has been successfully connected to the server via Socket.io.

💡 For the remaining part of this article, I will walk you through creating the web pages for the chat application and sending messages back and forth between the React app and the Node.js server. I'll also guide you on how to add the auto-scroll feature when a new message arrives and how to fetch active users in your chat application.

Creating the Home page for the chat application

In this section, we'll create the home page for the chat application that accepts the username and saves it to the local storage for identification.

Create a folder named components within the client/src folder. Then, create the Home page component.



cd src
mkdir components & cd components
touch Home.js
Enter fullscreen mode Exit fullscreen mode

Copy the code below into the Home.js file. The code snippet displays a form input that accepts the username and stores it in the local storage.



import React, { useState } from 'react';
import { useNavigate } from 'react-router-dom';

const Home = () => {
  const navigate = useNavigate();
  const [userName, setUserName] = useState('');

  const handleSubmit = (e) => {
    e.preventDefault();
    localStorage.setItem('userName', userName);
    navigate('/chat');
  };
  return (
    <form className="home__container" onSubmit={handleSubmit}>
      <h2 className="home__header">Sign in to Open Chat</h2>
      <label htmlFor="username">Username</label>
      <input
        type="text"
        minLength={6}
        name="username"
        id="username"
        className="username__input"
        value={userName}
        onChange={(e) => setUserName(e.target.value)}
      />
      <button className="home__cta">SIGN IN</button>
    </form>
  );
};

export default Home;
Enter fullscreen mode Exit fullscreen mode

Next, configure React Router to enable navigation between the pages of the chat application. A home and chat page is enough for this application.

Copy the code below into the src/App.js file.



import { BrowserRouter, Routes, Route } from 'react-router-dom';
import Home from './components/Home';
import ChatPage from './components/ChatPage';
import socketIO from 'socket.io-client';

const socket = socketIO.connect('http://localhost:4000');
function App() {
  return (
    <BrowserRouter>
      <div>
        <Routes>
          <Route path="/" element={<Home socket={socket} />}></Route>
          <Route path="/chat" element={<ChatPage socket={socket} />}></Route>
        </Routes>
      </div>
    </BrowserRouter>
  );
}

export default App;
Enter fullscreen mode Exit fullscreen mode

The code snippet assigns different routes for the Home and Chat page of the application using React Router v6 and passes the Socket.io library into the components. We'll create the Chat page in the upcoming section.

Navigate into the src/index.css file and copy the code below. It contains all the CSS required for styling this project.



@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@100;200;300;400;500;600;700;800;900&display=swap');

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: 'Poppins', sans-serif;
}
.home__container {
  width: 100%;
  height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}
.home__container > * {
  margin-bottom: 10px;
}
.home__header {
  margin-bottom: 30px;
}
.username__input {
  padding: 10px;
  width: 50%;
}
.home__cta {
  width: 200px;
  padding: 10px;
  font-size: 16px;
  cursor: pointer;
  background-color: #607eaa;
  color: #f9f5eb;
  outline: none;
  border: none;
  border-radius: 5px;
}
.chat {
  width: 100%;
  height: 100vh;
  display: flex;
  align-items: center;
}
.chat__sidebar {
  height: 100%;
  background-color: #f9f5eb;
  flex: 0.2;
  padding: 20px;
  border-right: 1px solid #fdfdfd;
}
.chat__main {
  height: 100%;
  flex: 0.8;
}
.chat__header {
  margin: 30px 0 20px 0;
}
.chat__users > * {
  margin-bottom: 10px;
  color: #607eaa;
  font-size: 14px;
}
.online__users > * {
  margin-bottom: 10px;
  color: rgb(238, 102, 102);
  font-style: italic;
}
.chat__mainHeader {
  width: 100%;
  height: 10vh;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px;
  background-color: #f9f5eb;
}
.leaveChat__btn {
  padding: 10px;
  width: 150px;
  border: none;
  outline: none;
  background-color: #d1512d;
  cursor: pointer;
  color: #eae3d2;
}
.message__container {
  width: 100%;
  height: 80vh;
  background-color: #fff;
  padding: 20px;
  overflow-y: scroll;
}

.message__container > * {
  margin-bottom: 10px;
}
.chat__footer {
  padding: 10px;
  background-color: #f9f5eb;
  height: 10vh;
}
.form {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.message {
  width: 80%;
  height: 100%;
  border-radius: 10px;
  border: 1px solid #ddd;
  outline: none;
  padding: 15px;
}
.sendBtn {
  width: 150px;
  background-color: green;
  padding: 10px;
  border: none;
  outline: none;
  color: #eae3d2;
  cursor: pointer;
}
.sendBtn:hover {
  background-color: rgb(129, 201, 129);
}
.message__recipient {
  background-color: #f5ccc2;
  width: 300px;
  padding: 10px;
  border-radius: 10px;
  font-size: 15px;
}
.message__sender {
  background-color: rgb(194, 243, 194);
  max-width: 300px;
  padding: 10px;
  border-radius: 10px;
  margin-left: auto;
  font-size: 15px;
}
.message__chats > p {
  font-size: 13px;
}
.sender__name {
  text-align: right;
}
.message__status {
  position: fixed;
  bottom: 50px;
  font-size: 13px;
  font-style: italic;
}
Enter fullscreen mode Exit fullscreen mode

We've created the home page of our chat application. Next, let's design the user interface for the chat page.

Creating the Chat page of the application

In this section, we'll create the chat interface that allows us to send messages and view active users.

chat-app interface

From the image above, the Chat page is divided into three sections, the Chat Bar - sidebar showing active users, the Chat Body containing the sent messages and the header, and the Chat Footer - the message box and the send button.

Since we've been able to define the layout for the chat page, you can now create the components for the design.

Create the ChatPage.js file and copy the code below into it. You will need to ChatBar, ChatBody, and ChatFooter components.



import React from 'react';
import ChatBar from './ChatBar';
import ChatBody from './ChatBody';
import ChatFooter from './ChatFooter';

const ChatPage = ({ socket }) => {
  return (
    <div className="chat">
      <ChatBar />
      <div className="chat__main">
        <ChatBody />
        <ChatFooter />
      </div>
    </div>
  );
};

export default ChatPage;
Enter fullscreen mode Exit fullscreen mode

The Chat Bar component

Copy the code below into the ChatBar.js file.



import React from 'react';

const ChatBar = () => {
  return (
    <div className="chat__sidebar">
      <h2>Open Chat</h2>

      <div>
        <h4 className="chat__header">ACTIVE USERS</h4>
        <div className="chat__users">
          <p>User 1</p>
          <p>User 2</p>
          <p>User 3</p>
          <p>User 4</p>
        </div>
      </div>
    </div>
  );
};

export default ChatBar;
Enter fullscreen mode Exit fullscreen mode

The Chat Body component

Here, we'll create the interface displaying the sent messages and the page headline.



import React from 'react';
import { useNavigate } from 'react-router-dom';

const ChatBody = () => {
  const navigate = useNavigate();

  const handleLeaveChat = () => {
    localStorage.removeItem('userName');
    navigate('/');
    window.location.reload();
  };

  return (
    <>
      <header className="chat__mainHeader">
        <p>Hangout with Colleagues</p>
        <button className="leaveChat__btn" onClick={handleLeaveChat}>
          LEAVE CHAT
        </button>
      </header>

      {/*This shows messages sent from you*/}
      <div className="message__container">
        <div className="message__chats">
          <p className="sender__name">You</p>
          <div className="message__sender">
            <p>Hello there</p>
          </div>
        </div>

        {/*This shows messages received by you*/}
        <div className="message__chats">
          <p>Other</p>
          <div className="message__recipient">
            <p>Hey, I'm good, you?</p>
          </div>
        </div>

        {/*This is triggered when a user is typing*/}
        <div className="message__status">
          <p>Someone is typing...</p>
        </div>
      </div>
    </>
  );
};

export default ChatBody;
Enter fullscreen mode Exit fullscreen mode

The Chat Footer component

Here, we'll create the input and the send button at the bottom of the chat page. The message and the username appear in the console after submitting the form.



import React, { useState } from 'react';

const ChatFooter = () => {
  const [message, setMessage] = useState('');

  const handleSendMessage = (e) => {
    e.preventDefault();
    console.log({ userName: localStorage.getItem('userName'), message });
    setMessage('');
  };
  return (
    <div className="chat__footer">
      <form className="form" onSubmit={handleSendMessage}>
        <input
          type="text"
          placeholder="Write message"
          className="message"
          value={message}
          onChange={(e) => setMessage(e.target.value)}
        />
        <button className="sendBtn">SEND</button>
      </form>
    </div>
  );
};

export default ChatFooter;
Enter fullscreen mode Exit fullscreen mode

Sending messages between the React app and the Socket.io server

In this section, you'll learn how to send messages from the React app to the Node.js server and vice-versa via Socket.io. To send the messages to the server, we will need to pass the Socket.io library into the ChatFooter - component that sends the messages.

Update the ChatPage.js file to pass the Socket.io library into the ChatFooter component.



import React from 'react';
import ChatBar from './ChatBar';
import ChatBody from './ChatBody';
import ChatFooter from './ChatFooter';

const ChatPage = ({ socket }) => {
  return (
    <div className="chat">
      <ChatBar />
      <div className="chat__main">
        <ChatBody />
        <ChatFooter socket={socket} />
      </div>
    </div>
  );
};

export default ChatPage;
Enter fullscreen mode Exit fullscreen mode

Update the handleSendMessage function in the ChatFooter component to send the message to the Node.js server.



import React, { useState } from 'react';

const ChatFooter = ({ socket }) => {
  const [message, setMessage] = useState('');

  const handleSendMessage = (e) => {
    e.preventDefault();
    if (message.trim() && localStorage.getItem('userName')) {
      socket.emit('message', {
        text: message,
        name: localStorage.getItem('userName'),
        id: `${socket.id}${Math.random()}`,
        socketID: socket.id,
      });
    }
    setMessage('');
  };
  return <div className="chat__footer">...</div>;
};

export default ChatFooter;
Enter fullscreen mode Exit fullscreen mode

The handleSendMessage function checks if the text field is empty and if the username exists in the local storage (sign-in from the Home page) before sending the message event containing the user input, username, the message ID generated, and the socket or client ID to the Node.js server.

Open the index.js file on the server, update the Socket.io code block to listen to the message event from the React app client, and log the message to the server's terminal.



socketIO.on('connection', (socket) => {
  console.log(`⚡: ${socket.id} user just connected!`);

  //Listens and logs the message to the console
  socket.on('message', (data) => {
    console.log(data);
  });

  socket.on('disconnect', () => {
    console.log('🔥: A user disconnected');
  });
});
Enter fullscreen mode Exit fullscreen mode

We’ve been able to retrieve the message on the server; hence, let's send the message to all the connected clients.



socketIO.on('connection', (socket) => {
  console.log(`⚡: ${socket.id} user just connected!`);

  //sends the message to all the users on the server
  socket.on('message', (data) => {
    socketIO.emit('messageResponse', data);
  });

  socket.on('disconnect', () => {
    console.log('🔥: A user disconnected');
  });
});
Enter fullscreen mode Exit fullscreen mode

Update the ChatPage.js file to listen to the message from the server and display it to all users.



import React, { useEffect, useState } from 'react';
import ChatBar from './ChatBar';
import ChatBody from './ChatBody';
import ChatFooter from './ChatFooter';

const ChatPage = ({ socket }) => {
  const [messages, setMessages] = useState([]);

  useEffect(() => {
    socket.on('messageResponse', (data) => setMessages([...messages, data]));
  }, [socket, messages]);

  return (
    <div className="chat">
      <ChatBar socket={socket} />
      <div className="chat__main">
        <ChatBody messages={messages} />
        <ChatFooter socket={socket} />
      </div>
    </div>
  );
};

export default ChatPage;
Enter fullscreen mode Exit fullscreen mode

From the code snippet above, Socket.io listens to the messages sent via the messageResponse event and spreads the data into the messages array. The array of messages is passed into the ChatBody component for display on the UI.

Update the ChatBody.js file to render the data from the array of messages.



import React from 'react';
import { useNavigate } from 'react-router-dom';

const ChatBody = ({ messages }) => {
  const navigate = useNavigate();

  const handleLeaveChat = () => {
    localStorage.removeItem('userName');
    navigate('/');
    window.location.reload();
  };

  return (
    <>
      <header className="chat__mainHeader">
        <p>Hangout with Colleagues</p>
        <button className="leaveChat__btn" onClick={handleLeaveChat}>
          LEAVE CHAT
        </button>
      </header>

      <div className="message__container">
        {messages.map((message) =>
          message.name === localStorage.getItem('userName') ? (
            <div className="message__chats" key={message.id}>
              <p className="sender__name">You</p>
              <div className="message__sender">
                <p>{message.text}</p>
              </div>
            </div>
          ) : (
            <div className="message__chats" key={message.id}>
              <p>{message.name}</p>
              <div className="message__recipient">
                <p>{message.text}</p>
              </div>
            </div>
          )
        )}

        <div className="message__status">
          <p>Someone is typing...</p>
        </div>
      </div>
    </>
  );
};

export default ChatBody;
Enter fullscreen mode Exit fullscreen mode

The code snippet above displays the messages depending on whether you or another user sent the message. Messages in green are the ones you sent, and red is messages from other users.

Congratulations 🥂, the chat application is now functional. You can open multiple tabs and send messages from one to another.

How to fetch active users from Socket.io

In this section, you'll learn how to get all the active users and display them on the Chat Bar of the chat application.

chat-app interface

Open the src/Home.js and create an event that listens to users when they sign in. Update the handleSubmit function as below:



import React, { useState } from 'react';
import { useNavigate } from 'react-router-dom';

const Home = ({ socket }) => {
  const navigate = useNavigate();
  const [userName, setUserName] = useState('');

  const handleSubmit = (e) => {
    e.preventDefault();
    localStorage.setItem('userName', userName);
    //sends the username and socket ID to the Node.js server
    socket.emit('newUser', { userName, socketID: socket.id });
    navigate('/chat');
  };
  return (...)
  ...
Enter fullscreen mode Exit fullscreen mode

Create an event listener that updates an array of users on the Node.js server whenever a user joins or leaves the chat application.



let users = [];

socketIO.on('connection', (socket) => {
  console.log(`⚡: ${socket.id} user just connected!`);
  socket.on('message', (data) => {
    socketIO.emit('messageResponse', data);
  });

  //Listens when a new user joins the server
  socket.on('newUser', (data) => {
    //Adds the new user to the list of users
    users.push(data);
    // console.log(users);
    //Sends the list of users to the client
    socketIO.emit('newUserResponse', users);
  });

  socket.on('disconnect', () => {
    console.log('🔥: A user disconnected');
    //Updates the list of users when a user disconnects from the server
    users = users.filter((user) => user.socketID !== socket.id);
    // console.log(users);
    //Sends the list of users to the client
    socketIO.emit('newUserResponse', users);
    socket.disconnect();
  });
});
Enter fullscreen mode Exit fullscreen mode

socket.on("newUser") is triggered when a new user joins the chat application. The user's details (socket ID and username) are saved into the users array and sent back to the React app in a new event named newUserResponse.
In socket.io("disconnect"), the users array is updated when a user leaves the chat application, and the newUserReponse event is triggered to send the updated the list of users to the client.

Next, let's update the user interface, ChatBar.js, to display the list of active users.



import React, { useState, useEffect } from 'react';

const ChatBar = ({ socket }) => {
  const [users, setUsers] = useState([]);

  useEffect(() => {
    socket.on('newUserResponse', (data) => setUsers(data));
  }, [socket, users]);

  return (
    <div className="chat__sidebar">
      <h2>Open Chat</h2>
      <div>
        <h4 className="chat__header">ACTIVE USERS</h4>
        <div className="chat__users">
          {users.map((user) => (
            <p key={user.socketID}>{user.userName}</p>
          ))}
        </div>
      </div>
    </div>
  );
};

export default ChatBar;
Enter fullscreen mode Exit fullscreen mode

The useEffect hook listens to the response sent from the Node.js server and collects the list of active users. The list is mapped into the view and updated in real-time.

Congratulations 💃🏻, we've been able to fetch the list of active users from Socket.io. Next, let's learn how to add some cool features to the chat application.

Optional: Auto-scroll and Notify users when a user is typing

In this section, you'll learn how to add the auto-scroll feature when you receive a new message and the typing feature that indicates that a user is typing.

Auto-scroll feature

Auto Scroll

Update the ChatPage.js file as below:



import React, { useEffect, useState, useRef } from 'react';
import ChatBar from './ChatBar';
import ChatBody from './ChatBody';
import ChatFooter from './ChatFooter';

const ChatPage = ({ socket }) => {
  const [messages, setMessages] = useState([]);
  const [typingStatus, setTypingStatus] = useState('');
  const lastMessageRef = useRef(null);

  useEffect(() => {
    socket.on('messageResponse', (data) => setMessages([...messages, data]));
  }, [socket, messages]);

  useEffect(() => {
    // 👇️ scroll to bottom every time messages change
    lastMessageRef.current?.scrollIntoView({ behavior: 'smooth' });
  }, [messages]);

  return (
    <div className="chat">
      <ChatBar socket={socket} />
      <div className="chat__main">
        <ChatBody messages={messages} lastMessageRef={lastMessageRef} />
        <ChatFooter socket={socket} />
      </div>
    </div>
  );
};

export default ChatPage;
Enter fullscreen mode Exit fullscreen mode

Update the ChatBody component to contain an element for lastMessageRef.



import React from 'react';
import { useNavigate } from 'react-router-dom';

const ChatBody = ({ messages, lastMessageRef }) => {
  const navigate = useNavigate();

  const handleLeaveChat = () => {
    localStorage.removeItem('userName');
    navigate('/');
    window.location.reload();
  };

  return (
    <>
      <div>
        ......
        {/* --- At the bottom of the JSX element ----*/}
        <div ref={lastMessageRef} />
      </div>
    </>
  );
};

export default ChatBody;
Enter fullscreen mode Exit fullscreen mode

From the code snippets above, lastMessageRef is attached to a div tag at the bottom of the messages, and its useEffect has a single dependency, which is the messages array. So, when the messages changes, the useEffect for the lastMessageRef re-renders.

Notify others when a user is typing

To notify users when a user is typing, we'll use the JavaScript onKeyDown event listener on the input field, which triggers a function that sends a message to Socket.io as below:



import React, { useState } from 'react';

const ChatFooter = ({ socket }) => {
  const [message, setMessage] = useState('');

  const handleTyping = () =>
    socket.emit('typing', `${localStorage.getItem('userName')} is typing`);

  const handleSendMessage = (e) => {
    e.preventDefault();
    if (message.trim() && localStorage.getItem('userName')) {
      socket.emit('message', {
        text: message,
        name: localStorage.getItem('userName'),
        id: `${socket.id}${Math.random()}`,
        socketID: socket.id,
      });
    }
    setMessage('');
  };
  return (
    <div className="chat__footer">
      <form className="form" onSubmit={handleSendMessage}>
        <input
          type="text"
          placeholder="Write message"
          className="message"
          value={message}
          onChange={(e) => setMessage(e.target.value)}
                    {/*OnKeyDown function*/}
          onKeyDown={handleTyping}
        />
        <button className="sendBtn">SEND</button>
      </form>
    </div>
  );
};

export default ChatFooter;
Enter fullscreen mode Exit fullscreen mode

From the code snippet above, the handleTyping function triggers the typing event whenever a user is typing into the text field. Then, we can listen to the typing event on the server and send a response containing the data to other users via another event called typingResponse.



socketIO.on('connection', (socket) => {
  // console.log(`⚡: ${socket.id} user just connected!`);
  // socket.on('message', (data) => {
  //   socketIO.emit('messageResponse', data);
  // });

  socket.on('typing', (data) => socket.broadcast.emit('typingResponse', data));

  // socket.on('newUser', (data) => {
  //   users.push(data);
  //   socketIO.emit('newUserResponse', users);
  // });

  // socket.on('disconnect', () => {
  //   console.log('🔥: A user disconnected');
  //   users = users.filter((user) => user.socketID !== socket.id);
  //   socketIO.emit('newUserResponse', users);
  //   socket.disconnect();
  // });
});
Enter fullscreen mode Exit fullscreen mode

Next, listen to the typingResponse event in the ChatPage.js file and pass the data into the ChatBody.js file for display.



import React, { useEffect, useState, useRef } from 'react';
import ChatBar from './ChatBar';
import ChatBody from './ChatBody';
import ChatFooter from './ChatFooter';

const ChatPage = ({ socket }) => {
  // const [messages, setMessages] = useState([]);
  // const [typingStatus, setTypingStatus] = useState('');
  // const lastMessageRef = useRef(null);

  // useEffect(() => {
  //   socket.on('messageResponse', (data) => setMessages([...messages, data]));
  // }, [socket, messages]);

  // useEffect(() => {
  //   // 👇️ scroll to bottom every time messages change
  //   lastMessageRef.current?.scrollIntoView({ behavior: 'smooth' });
  // }, [messages]);

  useEffect(() => {
    socket.on('typingResponse', (data) => setTypingStatus(data));
  }, [socket]);

  return (
    <div className="chat">
      <ChatBar socket={socket} />
      <div className="chat__main">
        <ChatBody
          messages={messages}
          typingStatus={typingStatus}
          lastMessageRef={lastMessageRef}
        />
        <ChatFooter socket={socket} />
      </div>
    </div>
  );
};

export default ChatPage;
Enter fullscreen mode Exit fullscreen mode

Update the ChatBody.js file to show the typing status to the users.



<div className="message__status">
  <p>{typingStatus}</p>
</div>
Enter fullscreen mode Exit fullscreen mode

Congratulations, you've just created a chat application!💃🏻

Feel free to improve the application by adding the Socket.io private messaging feature that allows users to create private chat rooms and direct messaging, using an authentication library for user authorization and authentication and a real-time database for storage.

Conclusion

Socket.io is a great tool with excellent features that enables us to build efficient real-time applications like sports betting websites, auction and forex trading applications, and of course, chat applications by creating lasting connections between web browsers and a Node.js server.

If you're looking forward to building a chat application in Node.js, Socket.io may be an excellent choice.

You can find the source code for this tutorial here: https://github.com/novuhq/blog/tree/main/open-chat-app-with-socketIO

Next article

In the next part of the series I am going to talk about connecting the chat-app into browser notifications (web-push), so you can inform users about new messages if they are offline.

Help me out!

If you feel like this article helped you understand WebSockets better! I would be super happy if you could give us a star! And let me also know in the comments ❤️
https://github.com/novuhq/novu
Image description

Thank you for reading!

Top comments (76)

Collapse
 
nevodavid profile image
Nevo David •

What should I write about next?

Collapse
 
joelbonetr profile image
JoelBonetR 🥇 •

You could fork the same project and just change the implementation details to "vanilla" websockets to see the differences with socket.io! 😁

Collapse
 
nevodavid profile image
Nevo David •

It's good to understand vanilla websockets, but I don't think it's so practical 🤣
You would now use it in production most chances 🙈

Thread Thread
 
joelbonetr profile image
JoelBonetR 🥇 •

Hahaha it depends on the case, here I found a good TL; DR on that 😁

Thread Thread
 
nevodavid profile image
Nevo David •

Don't forget that in socket.io they also implemented long polling for old browsers :)

Thread Thread
 
joelbonetr profile image
JoelBonetR 🥇 • • Edited

The way socket.io actually works is by assuming those are AJAX requests and once some communications had been exchanged it switches the protocol, thus it's not a protocol downgrade but an upgrade (you can check that in the network tab of chrome dev tools), also check the link in the last comment for more details. Is it convenient?

Well, web sockets has a good browser support so It depends on the use case of this "workaround" being more or less harmful.

Also note that socket.io has 4 different versions and both client and server need to implement the same version as far as I can remember, hence as soon as v5 appears you'll need to provide both v4 and v5 versions to avoid current clients software breaking and to provide latest stable version for new customers or customers that want to migrate (thinking on the use-case of providing just a backend as service).

Thread Thread
 
sorindezzy profile image
Raita Dezideriu •

Wooow dude that’s so very Amazing 98% ? That says a lots mate

Thread Thread
 
joelbonetr profile image
JoelBonetR 🥇 •

Basically any browser version released in 2012 or newer (more or less) except from Opera Mini which I don't even know why they keep adding it to the metrics 😅

Thread Thread
 
nevodavid profile image
Nevo David •

It's true and not true, it's like saying that compare to the population of the world, you child will be chinese, it's most likely not true :)
So while it's true that if you target the whole world with your app that might be the case.
But try to do the same for old enterprise companies, and I promise you, you will find some Windows XP :D

Thread Thread
 
joelbonetr profile image
JoelBonetR 🥇 •

😂😂
Well, that it's compatible with any browser version released in 2012 or newer is absolutely true. Some people around the world using older versions is a completely different topic 😁

I'd rather prefer the connection to be tested with the "newest" protocol and downgrade it if there's any incompatibility instead doing the opposite. It will add a delay to people with very very old devices and software and speed up the rest.

My logic is that people with very very old devices and software are already used to the slowness 😳I know it by experience, had a Pentium II with a 56Kb modem for more than 10 years, on those waiting times 100-200ms won't harm much, it's a little % overall 😅

Collapse
 
pusoy profile image
Jmaglinte •

Integrate *MongoDB * :D

Collapse
 
nevodavid profile image
Nevo David •

Haha, that's a good idea!

Thread Thread
 
pusoy profile image
Jmaglinte •

Thank you! can't wait for the next one.

Collapse
 
radualexandrub profile image
Radu-Alexandru B •

how to build a 3 paged app using Sanity.io and Next.js

Collapse
 
kumard3 profile image
Kumar Deepanshu •

Trpc with next js

Collapse
 
lexiebkm profile image
Alexander B.K. •

I think I need to start writing a real-time app, so this article is interesting. Although I may have seen other real-time sample apps, this one still is still worth reading.

Collapse
 
nevodavid profile image
Nevo David •

Thank you Alexander! In the next one I will continue this article on how to use Browser Notification on a new chat message, what do you think?

Collapse
 
lexiebkm profile image
Alexander B.K. •

That is interesting too, but it would be better if you use standard Web API whenever possible, unless you think it will need specific library for that purpose.

Thread Thread
 
nevodavid profile image
Nevo David •

What do you mean by "standard Web API whenever possible"? :)

Thread Thread
 
lexiebkm profile image
Alexander B.K. •

Because you mentioned about browser notification, I searched in MDN if there was a tools for that purpose. So I mean like this one : developer.mozilla.org/en-US/docs/W...
Of course, you are free to use other tools, library you have found suitable for that purpose.

Thread Thread
 
nevodavid profile image
Nevo David •

It will probably be "web-push" library that wraps all those tools

Thread Thread
 
lexiebkm profile image
Alexander B.K. •

Nice, I am waiting for that.
Actually, I also want to see how you handle global state management if there are cases for that. Specifically, how you use Redux, because I am learning Redux with the recommended way mentioned in the Redux doc, i.e using Redux Toolkit (RTK) and RTK Query.
But it is just fine if you don't use it in that app.

Thread Thread
 
nevodavid profile image
Nevo David •

Anything specific you would like to build with Redux?

Thread Thread
 
lexiebkm profile image
Alexander B.K. •

In my last project, I didn't use it, because I didn't learn it, it would take longer time before I could really use it. For global state management, I used a lib named reactN by Charles Stover which was easy to use.
But now that I realize in what case Redux is suitable for, I think I am going to use it for my nearest project.

Collapse
 
sorindezzy profile image
Raita Dezideriu •

Ya Da Best Mate well done 👍 I love 💕 your talent

Thread Thread
 
nevodavid profile image
Nevo David •

Thank you Raita! How are you? :)

Collapse
 
topninja profile image
topninja •

Hi, novu team.
This is so great.
I also checked your packages on github, 7.3k stars - so amzing.
Btw I want to know about nove.co platform's pricing.
This is free platform? I signed on platform but there's no payment setup.

Collapse
 
nevodavid profile image
Nevo David •

Hi Michael! We are currently on an open beta, we will introduce pricing very soon :)

Collapse
 
renanfranca profile image
Renan Franca • • Edited

Could it be self hosted for free at heruko?

Thread Thread
 
nevodavid profile image
Nevo David •

Not sure about Heruko, but I imagine you can.
It uses Mongodb, Redis :)
Try and let me know if it works for you!

Collapse
 
sachinchaurasiya profile image
Sachin Chaurasiya •

This is amazing, thanks for sharing @nevodavid

Collapse
 
nevodavid profile image
Nevo David •

Thank you Sachin!
Are you planning on building one? :)

Collapse
 
sachinchaurasiya profile image
Sachin Chaurasiya •

Yes , planning to build one in this weekend:)

Collapse
 
minaprogrammer profile image
MinaProgrammer • • Edited

useEffect(() => {
socket.on('messageResponse', (data) => setMessages([...messages, data]));
}, [socket, messages]);
You put messages is an array that maybe cause an infinite loop

useEffect(() => {
socket.on('messageResponse', (data) => setMessages(mess=>[...mess, data]));
}, [socket]);

Collapse
 
nevodavid profile image
Nevo David •

If you are building a chat app, make sure you post it here?

Collapse
 
sorindezzy profile image
Raita Dezideriu •

Could you tell me what really difference is between Facebook chat Messenger and your Chat that you just created please ?

Collapse
 
nevodavid profile image
Nevo David •

A lot, but I can't tell you for sure as I don't know the facebook architecture.
But for starter, they are probably using a database 😅

Collapse
 
iamndeleva profile image
iamndeleva •

Great article Nevo

Collapse
 
nevodavid profile image
Nevo David •

Thank you, iamndeleva!
How are you? :)

Collapse
 
iamndeleva profile image
iamndeleva •

I'm doing good ! Actually building similar chat application only that I'm incorporating a database and messaging will depend on whether the user is authenticated or not

Collapse
 
murtuzaalisurti profile image
Murtuzaali Surti •

this is awesome! I might build one in the future, and might use novu as a notification system!! 👀

Collapse
 
nevodavid profile image
Nevo David •

Haha that would be cool!
Maybe we can collaborate on a project :)

Collapse
 
sorindezzy profile image
Raita Dezideriu •

Wooow

Thread Thread
 
sorindezzy profile image
Raita Dezideriu •

Indeed love 💕 it very much it can be somehow Unicorn 🦄 you know !!

Collapse
 
kings5660 profile image
Kingsley •

Super project. Thank you for posting. Tremendous work

Collapse
 
nevodavid profile image
Nevo David •

Thank you Kingsley, feel free to fork it :)

Collapse
 
joelbonetr profile image
JoelBonetR 🥇 •

Nice one! Liked reading that post, recommending it right now 👌😁

Collapse
 
nevodavid profile image
Nevo David •

Thank you very much Joel!

View full discussion (76 comments)

Some comments may only be visible to logged-in visitors. Sign in to view all comments.

Read next

safdarali profile image

5 things I wish I knew as a Web Developer

Safdar Ali -

gav_o profile image

UI Verse

Gav -

nozibul_islam_113b1d5334f profile image

The Ultimate Guide to JavaScript Arrays: A Complete Method List (50 Topics)

Nozibul Islam -

gleidsonleite profile image

Implementing Semaphore with Redis: Ensuring Controlled Access to Resources in Node.js

Gleidson Leite da Silva -