Javascript: Convert base64 to a Blob

gistfile1

function dataURItoBlob(dataURI, callback) {
    // convert base64 to raw binary data held in a string
    // doesn't handle URLEncoded DataURIs - see SO answer #6850276 for code that does this
    var byteString = atob(dataURI.split(',')[1]);

    // separate out the mime component
    var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0]

    // write the bytes of the string to an ArrayBuffer
    var ab = new ArrayBuffer(byteString.length);
    var ia = new Uint8Array(ab);
    for (var i = 0; i < byteString.length; i++) {
        ia[i] = byteString.charCodeAt(i);
    }

    // write the ArrayBuffer to a blob, and you're done
    var bb = new BlobBuilder();
    bb.append(ab);
    return bb.getBlob(mimeString);
}

[Error: Creating blobs from 'ArrayBuffer' and 'ArrayBufferView' are not supported]}

Thanks @noonon its working! I would help converting it to TS

function dataURIToBlob(dataURI: string) {
  dataURI = dataURI.replace(/^data:/, '');

  const type = dataURI.match(/image\/[^;]+/)[0];
  const base64 = dataURI.replace(/^[^,]+,/, '');
  const arrayBuffer = new ArrayBuffer(base64.length);
  const typedArray = new Uint8Array(arrayBuffer);

  for (let i = 0; i < base64.length; i++) {
    typedArray[i] = base64.charCodeAt(i);
  }

  return new Blob([arrayBuffer], { type });
}

This is great! thank you @franconisi