API Slices: Cache Management
API Slices: Cache Management Utilities
The API slice object includes cache management utilities that are used for implementing optimistic updates. These are included in a util
field inside the slice object.
updateQueryData
updateQueryData
Signature
Parameters
endpointName
: a string matching an existing endpoint nameargs
: a cache key, used to determine which cached dataset needs to be updatedupdateRecipe
: an Immerproduce
callback that can apply changes to the cached state
Description
A Redux thunk action creator that, when dispatched, creates and applies a set of JSON diff/patch objects to the current state. This immediately updates the Redux state with those changes.
The thunk action creator accepts three arguments: the name of the endpoint we are updating (such as 'getPost'
), any relevant query arguments, and a callback function. The callback receives an Immer-wrapped draft
of the current state, and may modify the draft to match the expected results after the mutation completes successfully.
The thunk returns an object containing {patches: Patch[], inversePatches: Patch[], undo: () => void}
. The patches
and inversePatches
are generated using Immer's produceWithPatches
method.
This is typically used as the first step in implementing optimistic updates. The generated inversePatches
can be used to revert the updates by calling dispatch(patchQueryData(endpointName, args, inversePatches))
. Alternatively, the undo
method can be called directly to achieve the same effect.
patchQueryData
patchQueryData
Signature
A Redux thunk that applies a JSON diff/patch array to the cached data for a given query result. This immediately updates the Redux state with those changes.
The thunk accepts three arguments: the name of the endpoint we are updating (such as 'getPost'
), any relevant query arguments, and a JSON diff/patch array as produced by Immer's produceWithPatches
.
This is typically used as the second step in implementing optimistic updates. If a request fails, the optimistically-applied changes can be reverted by dispatching patchQueryData
with the inversePatches
that were generated by updateQueryData
earlier, or by calling the undo
method returned from dispatching updateQueryData
.
prefetch
prefetch
Signature
Description
A Redux thunk that can be used to manually trigger pre-fetching of data.
The thunk accepts three arguments: the name of the endpoint we are updating (such as 'getPost'
), any relevant query arguments, and a set of options used to determine if the data actually should be re-fetched based on cache staleness.
React Hooks users will most likely never need to use this directly, as the usePrefetch
hook will dispatch this thunk internally as needed when you call the prefetching function supplied by the hook.
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