index.js

const shell = require('shelljs');
const http = require('http');
const createHandler = require('node-gitlab-webhook');
const handler = createHandler([{
    path: '/webhook',
    secret: 'superS3cret'
  }
]); 

/* 
You can add webhook path as much as you need.
*/

http.createServer((req, res) => {
   handler(req, res, (err) => {
      res.sendCode = 404;
      res.end('No such location');
   });
}).listen(7777); // PORT

handler.on('error', function (err) {

  console.error('Error:', err.message)

})


handler.on('push', function (event) {

  console.log(event.payload);

  switch (event.path) {

    case '/webhook':
        console.log('Run Script');
        shell.exec('/root/deploy.sh'); // You bash script path
      break
    default:
      // do sth else or nothing
      break
  }
})