batch-other-utilities.js

export function usePhotos({}) {
  // ...
  
  const removePhotosLockedFlag = useCallback(
    (_pendingUpdates) =>
      setPhotos((_photos) =>
        _photos.map((photo) => {
          const updatedItem = _pendingUpdates[photo.id];
          if (updatedItem) {
            return Object.assign({}, photo, {
              [LOCKED_FLAG_KEY]: false,
            });
          }

          return photo;
        })
      ),
    [setPhotos]
  );

  const revertPhotosToOriginalState = useCallback(
    (originalPhotos) =>
      setPhotos((_photos) =>
        _photos.map((item) => {
          const originalItem = originalPhotos.find((photo) => photo.id === item.id) || item;

          return Object.assign({}, originalItem, { [LOCKED_FLAG_KEY]: false });
        })
      ),
    [setPhotos]
  );

  const applyUpdatesToPhotos = useCallback(
    (_pendingUpdates) =>
      setPhotos((_photos) =>
        _photos.map((photo) => {
          const batchUpdateItem = _pendingUpdates[photo.id];

          if (batchUpdateItem) {
            // Locked flag will indicate that item is being processed now
            // (sent in an API request and waiting for a response)
            return Object.assign({}, photo, batchUpdateItem, {
              [LOCKED_FLAG_KEY]: true,
            });
          }
          return photo;
        })
      ),
    [setPhotos]
  );

  const clearPendingUpdates = useCallback(() => setPendingUpdates({}), [setPendingUpdates]);
  
  // ...
}