Made far too many attempts at this for something that still ended up basic and shit. TLDR just use underbridge it is so awesome; requires DAW or MIDI editor though so maybe there is still an idea in here somewhere.
First version was opz-midi-display.
Started with an op-z-style 16 box grid where they light up red, tried to add detail view for each step to show start times. Much of this was me trying to muddle through what MIDI events look like.
Second version I tried to split the UI from the events/storage bits.
debugging and refactoring with gpt is hard.
debugging vs fixing things myself
Have been finding ways of making things easy to copy/paste.
"use constants" and things was good. but regression!
generating test data has been good. "generate tests with playwright" was less helpful so far.