fix(queryCache): merge defaultConfig options (TanStack#774)

Providing a `defaultConfig` to `makeQueryCache` will merge `shared`, `queries`, and `mutations`
objects instead of overwriting. This allows you to configure only some options.

Author: TuckerWhitehouse

src/core/queryCache.js

@@ -17,7 +17,22 @@ export function makeQueryCache({ frozen = false, defaultConfig } = {}) {
   const globalListeners = []
 
   const configRef = defaultConfig
-    ? { current: { ...defaultConfigRef.current, ...defaultConfig } }
+    ? {
+        current: {
+          shared: {
+            ...defaultConfigRef.current.shared,
+            ...defaultConfig.shared,
+          },
+          queries: {
+            ...defaultConfigRef.current.queries,
+            ...defaultConfig.queries,
+          },
+          mutations: {
+            ...defaultConfigRef.current.mutations,
+            ...defaultConfig.mutations,
+          },
+        },
+      }
     : defaultConfigRef
 
   const queryCache = {

src/core/tests/queryCache.test.js

@@ -1,5 +1,6 @@
 import { sleep } from './utils'
 import { queryCache, queryCaches } from '../'
+import { makeQueryCache } from '../queryCache'
 
 describe('queryCache', () => {
   afterEach(() => {
@@ -184,7 +185,10 @@ describe('queryCache', () => {
   test('query interval is cleared when unsubscribed to a refetchInterval query', async () => {
     const queryKey = 'key'
     const fetchData = () => Promise.resolve('data')
-    await queryCache.prefetchQuery(queryKey, fetchData, { cacheTime: 0, refetchInterval: 1 })
+    await queryCache.prefetchQuery(queryKey, fetchData, {
+      cacheTime: 0,
+      refetchInterval: 1,
+    })
     const query = queryCache.getQuery(queryKey)
     const instance = query.subscribe()
     instance.updateConfig(query.config)
@@ -224,4 +228,15 @@ describe('queryCache', () => {
     expect(newQuery.state.markedForGarbageCollection).toBe(false)
     expect(newQuery.state.data).toBe('data')
   })
+
+  test('makeQueryCache merges defaultConfig so providing a queryFn does not overwrite the default queryKeySerializerFn', async () => {
+    const queryFn = () => 'data'
+    const queryCache = makeQueryCache({
+      defaultConfig: { queries: { queryFn } },
+    })
+
+    expect(() => queryCache.buildQuery('test')).not.toThrow(
+      'config.queryKeySerializerFn is not a function'
+    )
+  })
 })