Convert a base64 encoded data URI to binary

dataUriToBinary.js

let convertDataURIToBinary = (dataURI) => {
  var BASE64_MARKER = ';base64,';
  var base64Index = dataURI.indexOf(BASE64_MARKER) + BASE64_MARKER.length;
  var base64 = dataURI.substring(base64Index);
  var raw = window.atob(base64);
  var rawLength = raw.length;
  var array = new Uint8Array(new ArrayBuffer(rawLength));

  for(var i = 0; i < rawLength; i++) {
    array[i] = raw.charCodeAt(i);
  }
  return array;
};