material-icons-browser-extension/scripts/build-src.js

const path = require('path');
const mkdirp = require('mkdirp');
const fs = require('fs-extra');
const Parcel = require('parcel-bundler');

const distPath = path.resolve(__dirname, '..', 'dist');
const srcPath = path.resolve(__dirname, '..', 'src');

mkdirp(distPath).then(src);

// copy src files

function src() {

  const copyCustomIcons = fs.copy(
    path.resolve(srcPath, 'customIcons'),
    path.resolve(distPath, 'icons')
  );

  const entryFile = path.resolve(srcPath, 'main.js');
  const parcelOptions = {
    watch: false,
    minify: true,
  }
  const bundler = new Parcel(entryFile, parcelOptions)
  const bundleMainScript = bundler.bundle();

  const copyManifest = fs.copy(
    path.resolve(srcPath, 'manifest.json'),
    path.resolve(distPath, 'manifest.json')
  );

  const copyExtensionLogos = fs.copy(path.resolve(srcPath, 'extensionIcons'), distPath);

  return Promise.all([copyCustomIcons, copyManifest, copyExtensionLogos, bundleMainScript]);
}