fix: make sure state is not updated when unmounted

src/react/useBaseQuery.ts

@@ -1,15 +1,18 @@
 import React from 'react'
 
+import { QueryObserverResult } from '../core/types'
 import { notifyManager } from '../core/notifyManager'
 import { QueryObserver } from '../core/queryObserver'
 import { useQueryErrorResetBoundary } from './QueryErrorResetBoundary'
 import { useQueryClient } from './QueryClientProvider'
 import { UseBaseQueryOptions } from './types'
+import { useIsMounted } from './useIsMounted'
 
 export function useBaseQuery<TQueryFnData, TError, TData, TQueryData>(
   options: UseBaseQueryOptions<TQueryFnData, TError, TData, TQueryData>,
   Observer: typeof QueryObserver
 ) {
+  const isMounted = useIsMounted()
   const queryClient = useQueryClient()
   const errorResetBoundary = useQueryErrorResetBoundary()
   const defaultedOptions = queryClient.defaultQueryObserverOptions(options)
@@ -63,8 +66,14 @@ export function useBaseQuery<TQueryFnData, TError, TData, TQueryData>(
   // Subscribe to the observer
   React.useEffect(() => {
     errorResetBoundary.clearReset()
-    return observer.subscribe(notifyManager.batchCalls(setCurrentResult))
-  }, [observer, errorResetBoundary])
+    return observer.subscribe(
+      notifyManager.batchCalls((result: QueryObserverResult) => {
+        if (isMounted()) {
+          setCurrentResult(result)
+        }
+      })
+    )
+  }, [observer, errorResetBoundary, isMounted])
 
   // Handle suspense
   if (observer.options.suspense || observer.options.useErrorBoundary) {

src/react/useIsFetching.ts

@@ -4,6 +4,7 @@ import { notifyManager } from '../core/notifyManager'
 import { QueryKey } from '../core/types'
 import { parseFilterArgs, QueryFilters } from '../core/utils'
 import { useQueryClient } from './QueryClientProvider'
+import { useIsMounted } from './useIsMounted'
 
 export function useIsFetching(filters?: QueryFilters): number
 export function useIsFetching(
@@ -14,6 +15,7 @@ export function useIsFetching(
   arg1?: QueryKey | QueryFilters,
   arg2?: QueryFilters
 ): number {
+  const isMounted = useIsMounted()
   const queryClient = useQueryClient()
   const [filters] = parseFilterArgs(arg1, arg2)
   const [isFetching, setIsFetching] = React.useState(
@@ -29,13 +31,15 @@ export function useIsFetching(
     () =>
       queryClient.getQueryCache().subscribe(
         notifyManager.batchCalls(() => {
-          const newIsFetching = queryClient.isFetching(filtersRef.current)
-          if (isFetchingRef.current !== newIsFetching) {
-            setIsFetching(newIsFetching)
+          if (isMounted()) {
+            const newIsFetching = queryClient.isFetching(filtersRef.current)
+            if (isFetchingRef.current !== newIsFetching) {
+              setIsFetching(newIsFetching)
+            }
           }
         })
       ),
-    [queryClient]
+    [queryClient, isMounted]
   )
 
   return isFetching

src/react/useIsMounted.ts

@@ -0,0 +1,17 @@
+import React from 'react'
+
+import { isServer } from '../core/utils'
+
+export function useIsMounted() {
+  const mountedRef = React.useRef(false)
+  const isMounted = React.useCallback(() => mountedRef.current, [])
+
+  React[isServer ? 'useEffect' : 'useLayoutEffect'](() => {
+    mountedRef.current = true
+    return () => {
+      mountedRef.current = false
+    }
+  }, [])
+
+  return isMounted
+}

src/react/useMutation.ts

@@ -14,6 +14,7 @@ import {
   MutationKey,
   MutationObserverResult,
 } from '../core/types'
+import { useIsMounted } from './useIsMounted'
 
 // HOOK
 
@@ -68,6 +69,7 @@ export function useMutation<
     | UseMutationOptions<TData, TError, TVariables, TContext>,
   arg3?: UseMutationOptions<TData, TError, TVariables, TContext>
 ): UseMutationResult<TData, TError, TVariables, TContext> {
+  const isMounted = useIsMounted()
   const options = parseMutationArgs(arg1, arg2, arg3)
   const queryClient = useQueryClient()
 
@@ -96,14 +98,13 @@ export function useMutation<
           (
             result: MutationObserverResult<TData, TError, TVariables, TContext>
           ) => {
-            // Check if the component is still mounted
-            if (observer.hasListeners()) {
+            if (isMounted()) {
               setCurrentResult(result)
             }
           }
         )
       ),
-    [observer]
+    [observer, isMounted]
   )
 
   const mutate = React.useCallback<

src/react/useQueries.ts

@@ -1,11 +1,14 @@
 import React from 'react'
 
+import { QueryObserverResult } from '../core/types'
 import { notifyManager } from '../core/notifyManager'
 import { QueriesObserver } from '../core/queriesObserver'
 import { useQueryClient } from './QueryClientProvider'
 import { UseQueryOptions, UseQueryResult } from './types'
+import { useIsMounted } from './useIsMounted'
 
 export function useQueries(queries: UseQueryOptions[]): UseQueryResult[] {
+  const isMounted = useIsMounted()
   const queryClient = useQueryClient()
 
   // Create queries observer
@@ -25,8 +28,15 @@ export function useQueries(queries: UseQueryOptions[]): UseQueryResult[] {
 
   // Subscribe to the observer
   React.useEffect(
-    () => observer.subscribe(notifyManager.batchCalls(setCurrentResult)),
-    [observer]
+    () =>
+      observer.subscribe(
+        notifyManager.batchCalls((result: QueryObserverResult[]) => {
+          if (isMounted()) {
+            setCurrentResult(result)
+          }
+        })
+      ),
+    [observer, isMounted]
   )
 
   return currentResult