Option to keep previous data in loadable when in loading state

[noodlefreeze]

Currently, loadable(atom) returns:

{ state: 'loading', data: undefined }

when the underlying async atom is pending.

In some UI patterns (infinite scrolling, polling refresh, optimistic updates), it is useful to keep the previous data during the loading phase, so the UI doesn't "flash empty".

[dai-shi]

First of all, this is not technically limited to loadable.

There's no concept of "previous" data in the Jotai atom model.
However, sometimes "previous" data would be handy.
So, we provide a workaround util, which is selectAtom.

In your case, async atom -> loadable -> selectAtom should do.

[noodlefreeze]

Thanks for the clarification and the selectAtom tip.

[dmaskasky]

atomWithHistory from jotai-history should help here.