existingUploadedFilenames = (uploadedFiles, currentFiles) => {
  if (
    (uploadedFiles && !uploadedFiles.length) ||
    (currentFiles && !currentFiles.length)
  ) {
    return [];
  }
  const currentFilenames = _.map(currentFiles, cf =>
    getFilenameFromPath(cf.path)
  );
  return _.chain(uploadedFiles)
    .filter(file => currentFilenames.includes(file.name))
    .map(file => file.name)
    .value();
}
returns the uploaded static files that are being overwritten
@param {Array} uploadedFiles
@param {Array} currentFiles
@return {Array} filenames