Electronic music in javascript

music.js

//        |   .   |   .   |   .   |   .   |
notes1 = '30934903403050302080473000102000';
notes2 = '90000010900100009000001090010000';
tAudio = 0;
audioCtx = new AudioContext;
scriptProcessor = audioCtx.createScriptProcessor(512, 0, 1);
scriptProcessor.connect(audioCtx.destination);
scriptProcessor.onaudioprocess = e => {
	data = e.outputBuffer.getChannelData(0);
	for (i = 0; i < data.length; i++)
		sample = 0,
		bpm = tAudio * 130 / 60,
		position = bpm * 4,

		// lead note
		noteIndex = position | 0,
		note1 = notes1[noteIndex%notes1.length],
		positionInNote = bpm%.5,
		data[i] = tAudio*note1*128 % 1
		        + (Math.random()-.5) * Math.pow(1-positionInNote, 16)
		        + (Math.random()-.5) / 1e3 * 512 * notes2[noteIndex%notes2.length] %1,
		tAudio += 1 / audioCtx.sampleRate
}