Spotify Waveform Data Generation from Audio Analysis API

spotify-waveform.js

const fs = require('fs')
const data = require('./track.json')

let duration = data.track.duration

let segments = data.segments.map(segment => {
  return {
    start: segment.start / duration,
    duration: segment.duration / duration,
    loudness: 1 - (Math.min(Math.max(segment.loudness_max, -35), 0) / -35)
  }
})

let min = Math.min(...segments.map(s => s.loudness))
let max = Math.max(...segments.map(s => s.loudness))

let levels = []

for (let i = 0.000; i < 1; i += 0.001) {
  let s = segments.find(segment => {
    return i <= segment.start + segment.duration
  })

  let loudness = Math.round((s.loudness / max) * 100) / 100

  levels.push(loudness)
}

fs.writeFile('levels.json', JSON.stringify(levels), (err) => {
  console.log(err)
})