Creating an Automated WhatsApp Web Bot with JavaScript and Expressjs

Prerequisites:

• Node.Js installed in your machine.
• A WhatsApp account with WhatsApp Web related.

Step 1: Set Up a New Node.Js Project

Create a new project and initialize it as a Node.Js:

mkdir whatsapp-bot

cd whatsapp-bot

npm init -y

Step 2: Install Required Libraries

You'll need the following libraries:

• qrcode-terminal: To display the QR code for WhatsApp Web authentication.
• Whatsapp-web.Js: A library for interacting with WhatsApp Web.
• express: To create a simple net server for receiving incoming messages.

Install those libraries using npm:

npm install qrcode-terminal whatsapp-web.Js express

Step 3: Create Your WhatsApp Bot

Create a JavaScript report, e.g., whatsapp-bot.Js, and upload the following code to set up your WhatsApp bot:

const qrcode = require('qrcode-terminal');
const { Client } = require('whatsapp-web.js');
const express = require('express');
const app = express();
const port = 8080;

app.use(express.json());

const client = new Client();

client.on('qr', (qr) => {
  qrcode.generate(qr, { small: true });
  console.log('Scan the QR code above to log in.');
});

client.on('ready', () => {
  console.log('WhatsApp bot is ready!');
});

client.on('message', (message) => {
  // Implement your message handling logic here
  if (message.body === 'Hello') {
    message.reply('Hello, I am your WhatsApp bot!');
  }
});

client.initialize();

app.post('/send-message', (req, res) => {
  const { number, message } = req.body;
  client.sendMessage(number, message).then(() => {
    res.status(200).json({ message: 'Message sent successfully' });
  }).catch((err) => {
    res.status(500).json({ error: err.message });
  });
});

app.listen(port, () => {
  console.log(`Server is running on port ${port}`);
});

Run your bot the use of the following command:

node whatsapp-bot.Js

This will start your Express.Js server on port 8080. The bot will display a QR code inside the terminal. Scan the QR code the usage of your WhatsApp cellular app to log in.

Step 5: Interact with Your Bot

You can ship a POST request in your Express.Js server to ship messages out of your bot:

curl -X POST http://localhost:8080/send-message -H "Content-Type: application/json" -d '{"number": "RECIPIENT_PHONE_NUMBER", "message": "Hello from my WhatsApp bot!"}'

Your bot will automatically reply with "Hello, I am your WhatsApp bot!" when it gets a "Hello" message.

This is a primary example of putting in place a WhatsApp Web bot with JavaScript and Express.Js. You can expand it to handle greater complicated common sense and commands as needed.