Logic Pro X Scripter MIDI FX that pitch shifts notes played in beats 1 and 3 of the bar

beatShifter.js

var shift = 0;

NeedsTimingInfo = true;

function HandleMIDI(event) {
	event.pitch += shift;
	event.send();
}

function ProcessMIDI () {
	var info = GetTimingInfo(),
		beat = (Math.floor(info.blockStartBeat) - 1) % info.meterDenominator;

	if (info.playing) {
		if (beat === 0 || beat === 2) {
			shift = 12;
		} else {
			shift = 0;
		}
	}
}