Create a local server using an ExpressJS application

To use an ExpressJS application:

1. Create a new application using npm init.
2. Install the ExpressJS library by using npm install express --save
3. Write the code:

    const express = require('express')
    const app = express()
    const port = 3000
    app.post('/webhook', function(req, res, next) {
    console.log(req.body)
    res.send(200)
    });
    app.listen(port, () => console.log(`Example app listening at http://localhost:${port}`))

4. To start your application, run the following command:

   node app.js

Your application will now print the events to the console when a call is made or received.