Download Audio from AJAX and Play as Blob

playAudioAsBlobViaAjax.js

var a = fetch("http://path/to/audio.wav")
  .then(res => {
    var reader = res.body.getReader();
    return reader.read().then(result => {
      return result;
    });
  })
  .then(data => {
    console.log(data);

    var blob = new Blob([data.value], { type: "audio/wav" });
    var blobUrl = URL.createObjectURL(blob);
    window.audio = new Audio();
    window.audio.src = blobUrl;
    window.audio.controls = true;
    document.body.appendChild(window.audio);
  });