docs: update getCachedData types (#31208)

docs/3.api/2.composables/use-async-data.md

@@ -74,7 +74,7 @@ The `handler` function should be **side-effect free** to ensure predictable beha
   - `transform`: a function that can be used to alter `handler` function result after resolving
   - `getCachedData`: Provide a function which returns cached data. A `null` or `undefined` return value will trigger a fetch. By default, this is:
     ```ts
-    const getDefaultCachedData = (key) => nuxtApp.isHydrating 
+    const getDefaultCachedData = (key, nuxtApp) => nuxtApp.isHydrating 
       ? nuxtApp.payload.data[key] 
       : nuxtApp.static.data[key]
     ```
@@ -141,7 +141,7 @@ type AsyncDataOptions<DataT> = {
   transform?: (input: DataT) => DataT | Promise<DataT>
   pick?: string[]
   watch?: WatchSource[]
-  getCachedData?: (key: string, nuxtApp: NuxtApp) => DataT
+  getCachedData?: (key: string, nuxtApp: NuxtApp) => DataT | undefined
 }
 
 type AsyncData<DataT, ErrorT> = {

docs/3.api/2.composables/use-fetch.md

@@ -111,7 +111,7 @@ All fetch options can be given a `computed` or `ref` value. These will be watche
   - `transform`: a function that can be used to alter `handler` function result after resolving
   - `getCachedData`: Provide a function which returns cached data. A `null` or `undefined` return value will trigger a fetch. By default, this is:
     ```ts
-    const getDefaultCachedData = (key) => nuxtApp.isHydrating 
+    const getDefaultCachedData = (key, nuxtApp) => nuxtApp.isHydrating 
       ? nuxtApp.payload.data[key] 
       : nuxtApp.static.data[key]
     ```
@@ -174,7 +174,7 @@ type UseFetchOptions<DataT> = {
   server?: boolean
   lazy?: boolean
   immediate?: boolean
-  getCachedData?: (key: string, nuxtApp: NuxtApp) => DataT
+  getCachedData?: (key: string, nuxtApp: NuxtApp) => DataT | undefined
   deep?: boolean
   dedupe?: 'cancel' | 'defer'
   default?: () => DataT