jsm makes a system's MIDI ports accessible to node applications. It uses the portmidi cross-platform media library, so it should work on MacOS, Windows and Linux.
jsm is designed to make it easy for node applications to send and receive MIDI messages. It was initially developed to implement flexible interfaces between control surfaces and synthesizers. Efficiency is a concern, too, but at this stage, there is no provision to make strict timing promises. This means that while it is possible to generate note messages, jitter and latency cannot be controlled tightly yet.
This is an example of a program that sends a few MIDI control messages:
var MIDI = require('MIDI');
var midiOutput = new MIDI.MIDIOutput();
console.log("opened MIDI output port", midiOutput.portName);
midiOutput.channel(3); // Set output channel 3
midiOutput.controlChange(0, 10); // Select bank 10 (CC0)
midiOutput.channel(4); // Set output channel 4
midiOutput.controlChange(7, 80); // Set volume to 80 (CC7)This is an example of a program that receives MIDI noteOn messages and prints them to the console:
var MIDI = require('MIDI');
var midiInput = new MIDI.MIDIInput();
console.log("opened MIDI input port", midiOutput.portName);
midiInput.on('noteOn',
function (pitch, velocity, channel) {
console.log('note', MIDI.pitchToNote(pitch),
'velocity', velocity,
'channel', channel);
});