code: function processBufferViewImage(blob) {
        if (!outputJSON.bufferViews) {
          outputJSON.bufferViews = [];
        }
  
        return new Promise(function(resolve) {
          var reader = new window.FileReader();
          reader.readAsArrayBuffer(blob);
          reader.onloadend = function() {
            var buffer = getPaddedArrayBuffer(reader.result);
  
            var bufferView = {
              buffer: processBuffer(buffer),
              byteOffset: byteOffset,
              byteLength: buffer.byteLength
            };
  
            byteOffset += buffer.byteLength;
  
            outputJSON.bufferViews.push(bufferView);
  
            resolve(outputJSON.bufferViews.length - 1);
          };
        });
      }
docs: Process and generate a BufferView from an image Blob.
  @param {Blob} blob
  @return {Promise<Integer>}