index.js

// Requests and decodes an MP3 file
// Encodes the audio data as WAV
// Then triggers a download of the file
var xhr = require('xhr')
var bufferToWav = require('../')

var audioContext = new (window.AudioContext || window.webkitAudioContext)()

xhr({
  uri: 'demo/bluejean_short.mp3',
  responseType: 'arraybuffer'
}, function (err, body, resp) {
  if (err) throw err

  var anchor = document.createElement('a')
  document.body.appendChild(anchor)
  anchor.style = 'display: none'

  audioContext.decodeAudioData(resp, function (buffer) {
    var wav = bufferToWav(buffer)
    var blob = new window.Blob([ new DataView(wav) ], {
      type: 'audio/wav'
    })

    var url = window.URL.createObjectURL(blob)
    anchor.href = url
    anchor.download = 'audio.wav'
    anchor.click()
    window.URL.revokeObjectURL(url)
  }, function () {
    throw new Error('Could not decode audio data.')
  })
})