I wrote something similar, but for the web. I call it "Literate Markdown" (
https://simpatico.io/lit.md) and you write markdown and your html/css/js/md code blocks are both exposed as text and as code blocks for execution in the browser. The format expects to a) be transformed and exposed by a special server (
https://simpatico.io/reflector.md) and b) rendered in a browser. This code also includes a simple test harness that, for example, turns the favicon green/red depending on if exceptions are thrown in your code (
https://simpatico.io/testable.js) I also wrote an acceptance test that loads most of the interesting parts of the site in iframes and combines their test output (
https://simpatico.io/acceptance). That page also has notes for using headless chrome to run the tests. Also, the server (lazily) caches all transforms with file watcher invalidation, disallows 3rd party cookies, and starts up instantly.
The central use case is to have a fun and fast way to play with browser code, using your favorite editor, and literate programming techniques. All while being open source, local first, and minimalist.
The repo (https://github.com/javajosh/simpatico/) is not yet npm/npx compatible so you have to fork and run. This is a local first, minimalist project that has ~2 small dependencies, which themselves have no deps, so publishing was not a priority.
Eventually I'd like to automate an md-> js process, such that the md is the canonical source for javascript and the final js is a build product. I'd also like to clean up the code and publish to npm, but sadly someone is squatting on the @simpatico handle and npm won't do anything. :(