Sample Javascript widget
Install these dependencies
npm install webpack webpack-dev-server copy-webpack-plugin --save-dev
npm install @babel/core @babel/preset-env babel-loader@next --save-dev
npm install css-loader html-loader style-loader --save-dev
To build files:
npm run build
To start server
npm start
Resources
https://www.robinwieruch.de/webpack-advanced-setup-tutorial#webpacks-development-and-production-build
https://blog.jenyay.com/building-javascript-widget/