Why does my Node.js app build not end in heroku?

Question

I'm trying to deploy an nodejs app to heroku, and the build doesn't complete, it stops once server starts running. Here are the photos of of my app:

1. The server

    const express = require('express');
    const bodyParser = require('body-parser');
    const path = require('path');
    const morgan = require('morgan');
    const app = express();
    require('dotenv').config();
    const port = process.env.PORT || 4000;

    // parse requests of content-type - application/x-www-form-urlencoded
    app.use(bodyParser.urlencoded({ extended: true }));

    // parse requests of content-type - application/json
    app.use(bodyParser.json());

    app.use(morgan('dev'));

    app.use(express.static('dist'));

    // database connection
    const db_conn = require('./models/mongoose-connection');
    db_conn.databaseConnection().catch((error) => console.error(error));

    // require routes
    app.use('/api', require('./routes/user'));

    // get routes from client-side
    app.get('/*', (req, res) => {
      res.sendFile(path.join(__dirname, '../dist', 'index.html'));
    });

    app.listen(port, () =>
      console.log('Express application booted, listening on %s.', port)
    );

2. The package.json scripts are as follows:

      "scripts": {
        "server": "node server/app.js",
        "build": "webpack --mode production && npm run server",
        "start": "webpack-dev-server --open"
      },

3. The app build process stops here and the build doesn't end.

bined asset size exceeds the recommended limit (244 KiB). This can impact web performance.
remote:        Entrypoints:
remote:          main (383 KiB)
remote:              bundle.js
remote:        
remote:        
remote:        WARNING in webpack performance recommendations: 
remote:        You can limit the size of your bundles by using import() or require.ensure to lazy load some parts of your application.
remote:        For more info visit https://webpack.js.org/guides/code-splitting/
remote:        Child HtmlWebpackCompiler:
remote:             1 asset
remote:            Entrypoint HtmlWebpackPlugin_0 = __child-HtmlWebpackPlugin_0
remote:            [0] ./node_modules/html-webpack-plugin/lib/loader.js!./public/index.html 498 bytes {0} [built]
remote:        
remote:        > blesser@1.0.0 server /tmp/build_b4b117004ecd6958331b75eea3eb8d3a
remote:        > node server/app.js
remote:        
remote:        Express application booted, listening on 4000.
remote:        Connection Established

Answer 1

Add Procfile at the root of the application with the following contents:

web: node server/app.js

This will be run once the deployment is done.