code: function base64ToBlob(base64) {
          // 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(base64.split(',')[1]);
  
          // separate out the mime component
          var mimeString = base64.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
          return new Blob([ab], { type: mimeString });
      }
docs: Convert base64 string to Blob object
  @param {String} base64
  @returns {Blob}