Dojo Project - Learning the Build Process for a React Web App

Summary

This is an open-source, lightweight, maintainable React app template.
It's built with as few dependencies and configurations as possible.
Toolchain is built from scratch with yarn, Parcel, React & GitHub Pages.
Official documentation of all tech is heavily referenced through the tutorial for best-practices.
Latest versions of all tech is used to reduce vulnerabilities.

Junior devs who have finished a bootcamp and want to know how to build a React web app all the way from scratch and understand things like .gitignore, a new, more secure package manager (yarn) other than npm, the package.json file, creating a dev environment, and deploying to production.
Devs who want to use Parcel & yarn to build any kind of website, whether React (this tutorial), or Bootstrap & Sass static site (this doc), etc.

This tutorial is for building a React app with one page and hosting on GitHub Pages (without a custom domain).
Note that this tutorial works with a GitHub Pages site, and not a GitHub user site (I tried, but it seems there's currently a bug).
I wanted to add multi-page SPA functionality with react-router-dom, but couldn't get react-router-dom BrowserRouter fully working. I think if you try a custom domain with GitHub Pages and configure the sitemap, it could possibly work. This is explained more in 9. react-router-dom experiment.