React & JSX related: using JSX without React, minimal setup for trying out React

using JSX without React:
https://itnext.io/lessons-learned-using-jsx-without-react-bbddb6c28561

Minimal React.js Without A Build Step:
https://shinglyu.github.io/web/2018/02/08/minimal-react-js-without-a-build-step-updated.html