function base64toBlob(base64Data, contentType) {
      contentType = contentType || '';
      var sliceSize = 1024;
      var byteCharacters = atob(base64Data);
      var bytesLength = byteCharacters.length;
      var slicesCount = Math.ceil(bytesLength / sliceSize);
      var byteArrays = new Array(slicesCount);

      for (var sliceIndex = 0; sliceIndex < slicesCount; ++sliceIndex) {
        var begin = sliceIndex * sliceSize;
        var end = Math.min(begin + sliceSize, bytesLength);

        var bytes = new Array(end - begin);
        for (var offset = begin, i = 0 ; offset < end; ++i, ++offset) {
          bytes[i] = byteCharacters[offset].charCodeAt(0);
        }
        byteArrays[sliceIndex] = new Uint8Array(bytes);
      }
      return new Blob(byteArrays, { type: contentType });
    }

    var somemockblob = base64toBlob('iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAYdEVYdFNvZnR3YXJlAHBhaW50Lm5ldCA0LjAuNWWFMmUAAAAMSURBVBhXY2BgYAAAAAQAAVzN/2kAAAAASUVORK5CYII=', 'image/png' )

someService,uploadFile(somemockblob); //->>returns TypeError: '[object BlobConstructor]' is not a constructor (evaluating 'new Blob(byteArrays, { type: contentType })')