About webMidi and Emscripten

I added webMidi to OF / Emscripten and search for a better implementation.
This is how I did it:
Add PLATFORM_LDFLAGS += --post-js $(OF_ADDONS_PATH)/ofxEmscripten/libs/html5audio/lib/emscripten/library_webMidi.js
to config.emscripten.default.mk.
This is the webMidi library that I use: https://github.com/Jonathhhan/openFrameworks/blob/AudioWorklet/addons/ofxEmscripten/libs/html5audio/lib/emscripten/library_webMidi.js
And this is the original file (I added output): https://github.com/cwilso/midi-synth/blob/master/js/midi.js

And I had to add this:

<b>Input Ports:&nbsp;</b><select id="midiIn"><option>-no MIDI-</option></select><br></p>
<b>Outputs Ports:&nbsp;</b><select id="midiOut"><option>-no MIDI-</option></select></p>

to template.html (for recognizing and selecting midi devices).

Then I can just send MIDI from ofApp.cpp to the MIDI device like this (for example):

			int array[3] = {val_0, val_1, val_2};
			size_t lengthOfArray = sizeof array / sizeof array[0];
			EM_ASM_(
			var data = new Uint32Array(HEAPU32.buffer, $0, $1);
			sendMIDI(data), array, lengthOfArray);

The most crucial part is how to select the MIDI devices (it all happens on the JS side now), but also other parts can be optimized. I guess, all in all it should not be very difficult to implement.

Review config.emscripten.default.mk, the proposed library_webMidi.js under ofxEmscripten/libs/html5audio/lib/emscripten, and template.html to understand the current MIDI integration points. Compare the example ofApp.cpp EM_ASM_ usage with the linked implementation; done should include selecting MIDI input and output devices in the browser and sending MIDI from an openFrameworks app.