refactor: narrow onSuccess/onError/onMutate/onSettled callback types to Promise<void> | void in persist-query-client

Previously, the `onSuccess`, `onError`, `onMutate`, and `onSettled` callbacks were typed as `() => Promise<unknown> | unknown`. While `unknown` is technically valid, it implies that the return value might be used, assigned, or further processed. However, throughout the codebase, these callbacks are invoked solely for their side effects, and their return values are always ignored. Narrowing the type to `Promise<void> | void` makes this intent explicit, clarifies that any return value will be discarded, and prevents misleading type signatures that suggest otherwise.

This commit narrows their types to `() => Promise<void> | void`, which more accurately reflects their intended use.

Author: braden-w

packages/angular-query-persist-client/src/with-persist-query-client.ts

@@ -20,8 +20,8 @@ import type { PersistQueryClientFeature } from '@tanstack/angular-query-experime
 
 type PersistQueryClientOptions = {
   persistOptions: Omit<PersistQueryClientOptionsCore, 'queryClient'>
-  onSuccess?: () => Promise<unknown> | unknown
-  onError?: () => Promise<unknown> | unknown
+  onSuccess?: () => Promise<void> | void
+  onError?: () => Promise<void> | void
 }
 
 /**

packages/query-core/src/mutationCache.ts

@@ -16,24 +16,24 @@ interface MutationCacheConfig {
     variables: unknown,
     context: unknown,
     mutation: Mutation<unknown, unknown, unknown>,
-  ) => Promise<unknown> | unknown
+  ) => Promise<void> | void
   onSuccess?: (
     data: unknown,
     variables: unknown,
     context: unknown,
     mutation: Mutation<unknown, unknown, unknown>,
-  ) => Promise<unknown> | unknown
+  ) => Promise<void> | void
   onMutate?: (
     variables: unknown,
     mutation: Mutation<unknown, unknown, unknown>,
-  ) => Promise<unknown> | unknown
+  ) => Promise<void> | void
   onSettled?: (
     data: unknown | undefined,
     error: DefaultError | null,
     variables: unknown,
     context: unknown,
     mutation: Mutation<unknown, unknown, unknown>,
-  ) => Promise<unknown> | unknown
+  ) => Promise<void> | void
 }
 
 interface NotifyEventMutationAdded extends NotifyEvent {

packages/query-core/src/query.ts

@@ -65,7 +65,7 @@ export interface FetchContext<
   TData,
   TQueryKey extends QueryKey = QueryKey,
 > {
-  fetchFn: () => unknown | Promise<unknown>
+  fetchFn: () => Promise<unknown> | unknown
   fetchOptions?: FetchOptions
   signal: AbortSignal
   options: QueryOptions<TQueryFnData, TError, TData, any>

packages/query-core/src/types.ts

@@ -1105,18 +1105,18 @@ export interface MutationOptions<
     data: TData,
     variables: TVariables,
     context: TContext,
-  ) => Promise<unknown> | unknown
+  ) => Promise<void> | void
   onError?: (
     error: TError,
     variables: TVariables,
     context: TContext | undefined,
-  ) => Promise<unknown> | unknown
+  ) => Promise<void> | void
   onSettled?: (
     data: TData | undefined,
     error: TError | null,
     variables: TVariables,
     context: TContext | undefined,
-  ) => Promise<unknown> | unknown
+  ) => Promise<void> | void
   retry?: RetryValue<TError>
   retryDelay?: RetryDelayValue<TError>
   networkMode?: NetworkMode

packages/react-query-persist-client/src/PersistQueryClientProvider.tsx

@@ -11,8 +11,8 @@ import type { OmitKeyof, QueryClientProviderProps } from '@tanstack/react-query'
 
 export type PersistQueryClientProviderProps = QueryClientProviderProps & {
   persistOptions: OmitKeyof<PersistQueryClientOptions, 'queryClient'>
-  onSuccess?: () => Promise<unknown> | unknown
-  onError?: () => Promise<unknown> | unknown
+  onSuccess?: () => Promise<void> | void
+  onError?: () => Promise<void> | void
 }
 
 export const PersistQueryClientProvider = ({