A web based DAW type app for music production with instrument modules, piano roll etc.

https://errozero-metronic-studio-718699.netlify.app/

Click on the button with the piano icon at the top to test out the piano roll. You can play notes with the typing keyboard.

I got much further than this previously but decided to throw a lot of the code away and start again. I spent a load of time building a custom UI library before starting with things like draggable windows, linked scroll containers, dropdown menus etc.