I've been using this for personal use for around 2 years and I figured it was time to share it with the world. Criticism, issues and PRs are welcome. Thanks!
It's good that you made an alternative but it's not serious. I need to run Firefox, enable JS, reload the page, there is no "top menu" or install button, the open/save button does nothing, I can't choose my own fonts, and I guess it doesn't work if I don't have an internet connection.
> What's wrong with TextEdit on macOS?
Nothing wrong as such, but does it match the “cross-platform” description?
> Firefox … the open/save button does nothing
As per the readme, it is using an API that is not yet supported in Firefox for local file access: https://caniuse.com/native-filesystem-api
> there is no "top menu" or install button
That is meaning the browser's menu. Perhaps there is better terminology that should be used here. The readme does show a screenshot of it, so it seems clear from that to me. The install option is found there.
> and I guess it doesn't work if I don't have an internet connection.
Also in the readme: “Installable as a PWA”, which I think implies offline support, given it doesn't have sync features so has no reason once installed that way to talk to the wider network.
I'm sure this varies but, for me, on macOS Chrome, it's the '3 vertical dots' menu in the top right of the browser window. Very confusing instructions.
I also see an "Install Notepad" icon in my address bar, just to the left of the Bookmark icon. I never look in this area, though, so I totally missed it.