Convert to Blob with Javascript

b64toBlob.js

//By https://codedump.io/share/Fd3DmsM6UAeS/1/creating-a-blob-from-a-base64-string-in-javascript
//Example
//var blob = b64toBlob(b64Data, contentType);
//var blobUrl = URL.createObjectURL(blob);
function b64toBlob(b64Data, contentType, sliceSize) {
  contentType = contentType || 'image/png';
  sliceSize = sliceSize || 512;

  var byteCharacters = atob(b64Data);
  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);
  }

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

dataURLtoBlob.js

//Example var file = dataURLtoBlob(canvas.toDataURL());
function dataURLtoBlob(dataURL) {
    // Decode the dataURL   
    var binary = atob(dataURL.split(',')[1]);
    // Create 8-bit unsigned array
    var array = [];
    for (var i = 0; i < binary.length; i++) {
        array.push(binary.charCodeAt(i));
    }
    // Return our Blob object
    return new Blob([new Uint8Array(array)], { type: 'image/png' });
}

Real source: https://stackoverflow.com/questions/16245767/creating-a-blob-from-a-base64-string-in-javascript

Excellent, thanks! 👍