keepPreviousData

function keepPreviousData<T>(previousData: T | undefined): T | undefined;

Defined in: packages/query-core/src/utils.ts:578

Intended to be passed as a query's placeholderData option, for example placeholderData: keepPreviousData. Instead of resetting the query's data to undefined while a new query key is fetching, it keeps displaying the previously fetched data until the new data arrives.

Type Parameters#

T#

T

Parameters#

previousData#

The data of the previous query key, passed by the observer.

T | undefined

Returns#

T | undefined

The previous data, unchanged.

Example#

new QueryObserver(queryClient, {
  queryKey: ['posts', page],
  queryFn: () => fetchPosts(page),
  placeholderData: keepPreviousData,
})