build.js

const build = () => {
  const bundler = new Bundler(paths.appHtml, {
    command: 'build',
    outDir: paths.appBuild,
    publicUrl: './',
    cacheDir: './.parcelCache',
    // Generate Source Maps for prod
    sourceMaps: true,
  });

  Promise.resolve(bundler.bundle()).then(() => {
    copyPublicFolder();
    console.log('The ' + chalk.cyan('build') + ' folder is ready to be deployed.');
    console.log('You may also serve it locally with a static server:')
    console.log();
  }).catch((err) => {
    printErrors('Failed to compile.', [err]);
    process.exit(1);
  });
}

build();

Cheers! Much appreciated :)