SimpleWav Cross-browser base64 encoded wav file player api aimed at supporting wav in IE

SimpleWav.js

/*
* IE can't play wav files in the javascript audio api, or audio element.
* This is a cross browser base64 wav file player aimed at being very simple
* and small while still supporting IE.
* (C)2020 Rickey Ward
* MIT Licence
*/

(function () {
  window.simpleWav = {
    isAudioPlaying: false,
    fallbackPlayer: null,
    fallbackPlayerTimeout: null,
    fallbackPlayerObjectURL: null,
    audioPlayerLastCallaback: null,
    canPlayWavs: true
  }

  try {
    window.simpleWav.CanPlayWavs = new Audio().canPlayType('audio/wav') !== '';
  } catch (e) {
    window.simpleWav.CanPlayWavs = false;
  }

  window.simpleWav.PlayWav = function (b64Wav, endedCallback, durMs) {

    try {
      //stop if playing
      window.simpleWav.StopWav(true);

      window.simpleWav.audioPlayerLastCallaback = endedCallback;

      if (!window.simpleWav.CanPlayWavs) { //ie
        window.simpleWav.fallbackPlayer = document.createElement('bgsound');
        window.simpleWav.fallbackPlayer.setAttribute('id', 'fallbackWavPlayer');
        window.simpleWav.fallbackPlayerObjectURL = URL.createObjectURL(window.simpleWav.b64toBlob(b64Wav));
        window.simpleWav.fallbackPlayer.setAttribute('src', window.simpleWav.fallbackPlayerObjectURL);
        document.body.appendChild(window.simpleWav.fallbackPlayer);
        window.simpleWav.fallbackPlayerTimeout = setTimeout(function () {
          endedCallback && endedCallback();
        }, durMs || 2000); //If you know the length of the audio, bgsound doesn't detect end of play
      } else {
        window.simpleWav.audioPlayer = new Audio("data:audio/wav;base64," + b64Wav);
        window.simpleWav.audioPlayer.addEventListener("ended", function (event) {
          endedCallback && endedCallback(event);
        });
        window.simpleWav.audioPlayer.addEventListener("canplaythrough", function () {
          window.simpleWav.audioPlayer.play();
        });
      }
    } catch (error) {
      window.simpleWav.audioPlayerLastCallaback = null;
      endedCallback && endedCallback();
    }

  }

  window.simpleWav.StopWav = function (triggerCallback) {
    if (!window.simpleWav.CanPlayWavs) {
      window.simpleWav.fallbackPlayerTimeout && clearTimeout(window.simpleWav.fallbackPlayerTimeout);
      if (window.simpleWav.fallbackPlayer != null) {
        window.simpleWav.fallbackPlayer.setAttribute('src', '');
        document.body.removeChild(window.simpleWav.fallbackPlayer);
        window.simpleWav.fallbackPlayer = null;
      } else if (document.querySelector('bgsound')) {
        var cur = document.querySelector('bgsound');
        cur.setAttribute('src', '');
        document.body.removeChild(cur);
      }
      if (window.simpleWav.fallbackPlayerObjectURL) {
        URL.revokeObjectURL(window.simpleWav.fallbackPlayerObjectURL);
        window.simpleWav.fallbackPlayerObjectURL = null;
      }
    } else {
      if (window.simpleWav.audioPlayer) {
        //must have ended or be paused to be elligbile for garbage collection
        window.simpleWav.audioPlayer.pause();
        window.simpleWav.audioPlayer = null;
      }
    }

    if (window.simpleWav.audioPlayerLastCallaback && !triggerCallback) {
      window.simpleWav.audioPlayerLastCallaback();
      window.simpleWav.audioPlayerLastCallaback = null;
    }
  }

  /* This has been copied and pasted from different projects based on something from stack overflow years ago */
  window.simpleWav.b64toBlob = function (b64Data, contentType = '', sliceSize = 512) {
    contentType = contentType || '';
    sliceSize = sliceSize || 512;
    var byteCharacters = window.atob(b64Data.trim());
    var byteArrays = [];

    for (var offset = 0; offset < byteCharacters.length; offset += sliceSize) {
      var slice = byteCharacters.slice(offset, offset + sliceSize);

      var byteNumbers = new Array(slice.length);
      for (var i = 0; i < slice.length; i++) {
        byteNumbers[i] = slice.charCodeAt(i);
      }

      var byteArray = new Uint8Array(byteNumbers);

      byteArrays.push(byteArray);
    }

    return new Blob(byteArrays, {
      type: contentType
    });
  }
})();