This package is a generator for MIDI file from Array of Array. Here is a sample code.

const mdpw = require("mdpw"); var a = ['s',['n',64,1,64,1],['n',68,1,64,1],['n',71,1,64,1], ['c',['n',64,1,64,1],['n',68,1,64,1],['n',71,1,64,1]]]; var p = mdpw.compile(a, 120); mdpw.save(p, "sample.mid");

'n' means a note and followed values are pitch, duration, velocity and instrument. The instrument 129 means Drum. 's' means to play sequentially and 'c' means to play simultaneously.