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Nevo David for novu

Posted on • Originally published at novu.co

Building a chat app with Socket.io and React πŸš€

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.

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

cd client
npx create-react-app ./
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Install Socket.io client API and React Router.Β React RouterΒ is a JavaScript library that enables us to navigate between pages in a React application.

npm install socket.io-client react-router-dom
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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>
  );
}
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Next, navigate into the server folder and create a package.json file.

cd server
npm init -y
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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.Β 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, andΒ Socket.io allows us to configure a real-time connection on the server.

npm install express cors nodemon socket.io 
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Create an index.js file - the entry point to the web server.

touch index.js
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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}`);
});
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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}`);
});
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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('πŸ”₯: A user disconnected');
    });
});
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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"
  },
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You can now run the server with Nodemon by using the command below.

npm start
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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>
  );
}
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Start the React.js server.

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

Congratulations πŸ₯‚ , the React app has been successfully connected to the server via Socket.io.

πŸ’‘ 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
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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;
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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;
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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 theΒ 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;
}
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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;
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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;
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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;
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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;
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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;
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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;
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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('πŸ”₯: A user disconnected');
  });
});
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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('πŸ”₯: A user disconnected');
  });
});
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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;
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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;
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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 πŸ₯‚, 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 (...)
  ...
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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('πŸ”₯: 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();
  });
});
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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;
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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 πŸ’ƒπŸ», 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(() => {
    // πŸ‘‡οΈ 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;
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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;
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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;
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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('πŸ”₯: A user disconnected');
  //   users = users.filter((user) => user.socketID !== socket.id);
  //   socketIO.emit('newUserResponse', users);
  //   socket.disconnect();
  // });
});
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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(() => {
  //   // πŸ‘‡οΈ 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;
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Update the ChatBody.js file to show the typing status to the users.

<div className="message__status">
  <p>{typingStatus}</p>
</div>
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Congratulations, you've just created a chat application!πŸ’ƒπŸ»

Feel free to improve the application by adding the Socket.io private messaging feature that allows users to createΒ private chat roomsΒ andΒ 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 (68)

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nevodavid profile image
Nevo David

What should I write about next?

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joelbonetr profile image
JoelBonetR πŸ₯‡

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

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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 πŸ™ˆ

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joelbonetr profile image
JoelBonetR πŸ₯‡

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

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nevodavid profile image
Nevo David

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

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joelbonetr profile image
JoelBonetR πŸ₯‡ • 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).

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sorindezzy profile image
Raita Dezideriu

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

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joelbonetr profile image
JoelBonetR πŸ₯‡

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 πŸ˜…

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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

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joelbonetr profile image
JoelBonetR πŸ₯‡

πŸ˜‚πŸ˜‚
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 πŸ˜…

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pusoy profile image
Jmaglinte

Integrate *MongoDB * :D

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nevodavid profile image
Nevo David

Haha, that's a good idea!

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pusoy profile image
Jmaglinte

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

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kumard3 profile image
Kumar Deepanshu

Trpc with next js

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radualexandrub profile image
Radu-Alexandru B

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

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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.

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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?

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sorindezzy profile image
Raita Dezideriu

Ya Da Best Mate well done πŸ‘ I love πŸ’• your talent

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nevodavid profile image
Nevo David

Thank you Raita! How are you? :)

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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.

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nevodavid profile image
Nevo David

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

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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.

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nevodavid profile image
Nevo David

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

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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.

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nevodavid profile image
Nevo David

Anything specific you would like to build with Redux?

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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.

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topninja profile image
Michael

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.

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nevodavid profile image
Nevo David

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

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renanfranca profile image
Renan Franca • Edited

Could it be self hosted for free at heruko?

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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!

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sachinchaurasiya profile image
Sachin Chaurasiya

This is amazing, thanks for sharing @nevodavid

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nevodavid profile image
Nevo David

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

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sachinchaurasiya profile image
Sachin Chaurasiya

Yes , planning to build one in this weekend:)

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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]);

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iamndeleva profile image
iamndeleva

Great article Nevo

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nevodavid profile image
Nevo David

Thank you, iamndeleva!
How are you? :)

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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

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nevodavid profile image
Nevo David

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

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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 ?

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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 πŸ˜…

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murtuzaalisurti profile image
Murtuzaali Surti

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

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nevodavid profile image
Nevo David

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

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sorindezzy profile image
Raita Dezideriu

Wooow

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sorindezzy profile image
Raita Dezideriu

Indeed love πŸ’• it very much it can be somehow Unicorn πŸ¦„ you know !!

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nevodavid profile image
Nevo David

Hi Everybody!
I have released the second part here:
dev.to/novu/building-a-chat-browse...

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joelbonetr profile image
JoelBonetR πŸ₯‡

Nice one! Liked reading that post, recommending it right now πŸ‘ŒπŸ˜

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nevodavid profile image
Nevo David

Thank you very much Joel!

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kings5660 profile image
Kingsley

Super project. Thank you for posting. Tremendous work

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nevodavid profile image
Nevo David

Thank you Kingsley, feel free to fork it :)

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nevodavid profile image
Nevo David

Did you build your native chat in your app, or used something like intercom?

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nevodavid profile image
Nevo David

Just a quick reminder if you can help me out with a star on Novu ❀️❀️❀️❀️
github.com/novuhq/novu

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godwin_nj profile image
Amadi Godwin

Thanks for this , it was really helpful .

while building, if you want to remove user name that's typing on the body of that chat, setup another event with an empty string as its data , listen on both ends

 useEffect(() => {
    socket.on("typingResponse", (data) => setTypingStatus(data));
    setTimeout(() => {
      socket.on("noTypingResponse", (data) => setTypingStatus(data));
    }, 5000);
  }, [socket]);
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kevinguo profile image
Kevin Guo

Scaling Socket.IO apps on Azure. πŸ₯³βš‘οΈπŸ“£
Azure now officially supports Socket.IO. No more deploying and managing "adapter" component on the server side. Simplified architecture for the happy developer.Learn more about Socket.IO on Azure