The repo contains sample projects that were originally implemented in a JavaScript framework and have been reimplemented here using vanilla JS. The point of this project is to show the native power of the browser and to try to dispel the notion that building for the web requires a framework.
There are two ported projects so far:
The Vue.js sample app rewrite is the simplest port, using no external libraries at all, and using template literals for templating.
The React sample app rewrite uses only one additional library, lit-html for templating.
The Angular TODO app rewrite uses only one additional library, hyperHTML for templating.
This code works w/o polyfils in Chrome. To get it to run in a wider range of browsers you will need to add polyfills and, depending on the target browser version, compile the JS back to an older version of ES, and run a prefixer on the CSS. The wider the target set of browsers and the older the versions you are targeting the more processing you will need to do via webpack, but since the original code doesn't need to change, those extra processing steps are out of scope for these examples.