fix(solid-query/examples): guard prefetchQuery with isServer in solid-start-streaming

.changeset/slimy-peaches-pull.md

@@ -0,0 +1,4 @@
+---
+---
+
+fix(solid-query/examples): guard the `prefetchQuery` call in the solid-start-streaming example's `/prefetch` route with `isServer || intent !== 'initial'`, so it only runs on the server and on real client-side preload/navigation, not on every client hydration, fixing the duplicate fetch reported in #8840

examples/solid/solid-start-streaming/src/routes/prefetch.tsx

@@ -1,13 +1,24 @@
 import { useQueryClient } from '@tanstack/solid-query'
 import { isServer } from 'solid-js/web'
 import { Title } from '@solidjs/meta'
+import type { RoutePreloadFuncArgs } from '@solidjs/router'
 import { UserInfo, userInfoQueryOpts } from '~/components/user-info'
 
 export const route = {
-  load: () => {
-    const queryClient = useQueryClient()
-    // Prefetching the user info and caching it for 15 seconds.
-    queryClient.prefetchQuery(userInfoQueryOpts({ sleep: 500, gcTime: 15000 }))
+  load: ({ intent }: RoutePreloadFuncArgs) => {
+    // The router re-runs `load` on the client during hydration, with the
+    // same `intent: "initial"` the server call gets. UserInfo's useQuery
+    // already hydrates that data on the client through its own resource,
+    // so prefetching again here just duplicates the fetch. Hover preload
+    // (`intent: "preload"`) and real navigation (`intent: "navigate"`)
+    // still need to run, since neither has server-rendered data to use.
+    if (isServer || intent !== 'initial') {
+      const queryClient = useQueryClient()
+      // Prefetching the user info and caching it for 15 seconds.
+      queryClient.prefetchQuery(
+        userInfoQueryOpts({ sleep: 500, gcTime: 15000 }),
+      )
+    }
   },
 }