Convert midi files outputted by ableton into a json file with time of every note

midiToJSON.js

const { Midi } = require('@tonejs/midi')
const { readFileSync, writeFileSync } = require('fs')
const FILENAME = process.argv[2]
const BPM = process.argv[3]
const DIR_SPECIFIC = process.argv[4] === "true"

const MS_PER_MINUTE = 60000
const ABLETON_PPQ = 96

try {
    const msPerTick = (MS_PER_MINUTE / (BPM * ABLETON_PPQ))
    
    const data = {}

    for (let i = 5; i < process.argv.length; i++) {
      let midiUrl = process.argv[i]

      let trackName
      if (DIR_SPECIFIC) {
        // if we are using specific LRUD dirs, we have tracks tied to a specific dir
        trackName = midiUrl.split('=')[0]
        midiUrl = midiUrl.split('=')[1]
      } else {
        trackName = midiUrl.slice(0, midiUrl.indexOf('.mid'))
      }

      const midi = new Midi(readFileSync(midiUrl))
      const notes = midi.tracks[0].notes.map(({ ticks }) => ticks * msPerTick)
      data[trackName] = notes
    }

    let name = FILENAME + '.json'
    writeFileSync(name, JSON.stringify(data, null, 2), 'utf8')
    console.info(`SUCCESS! \n"${name}" created.`)
} catch (e) {
  console.error(
    'FAILED!\n' +
    'Usage: node midiToJson.js [Exported Track Name] [BPM] [=true] [dir=track-1] [dir=track-2]...[track-4]\n' +
    'OR: node midiToJson.js [Exported Track Name] [BPM] [=false] [track-1] [track-2]...[track-n]\n'
  )
}

// sample query:
// node midiToJSON.js think 132 true left=midi/think-left.mid right=midi/think-right.mid up=midi/think-up.mid down=midi/think-down.mid
// or for non-dir spcific track names:
// node midiToJSON.js think 132 false think-left.mid think-right.mid think-up.mid think-down.mid