Customizable layout of a whole day in your current timezone and as many other timezones as you like. Also shows the current hour. This is really good when an online friend says something will be at 10am her time and you need to know when to be awake in your timezone!
Interactive display of which notes on a piano keyboard are struck for a particular key and scale (mode).
Nano Apps are very very small browser apps - so small, in fact, that they have absolutely no server-side code at all. Hosting is 100% static files. You could run them in your browser from your local file system.
But what makes them apps, then?
Client-side JavaScript. Written by hand, not generated. No frameworks. Even the HTML markup and styles are hand-written. This is all what makes then Nano Apps. I mean, "nano" is smaller than "micro"... (And domain names like 'microapp' were either already taken or very expensive.) I will admit more than about 50 lines of JavaScript starts to need some serious discipline and structure, but it's clearly very possible!
Okay, there might be some third-party libraries, mostly to do things that JavaScript is not good at. Like date handling. Currently, the preference for date handling is Luxon which is small and non-intrusive.
Okay, so I've moved all my code (old and new...) off of both GitHub and BitBucket and started puttihg it on Codeberg. (GitHub has the problem that it is owned by Microsoft and they've been known to train their LLM on public repositories. BitBucket, which is where I was most recently, is part of Atlassian and as a company, they're doubling-down on LLM stuff, too.)