react-doctor/query-no-void-query-fn

queryFn must return a value for the cache. Use the `enabled` option to conditionally disable the query instead of returning undefined

• Category: TanStack Query
• Severity: warn
• Source: oxlint-plugin-react-doctor
• Framework: tanstack-query
• Enabled when: framework=tanstack-query and capabilities=tanstack-query

Validation prompt

Use this to decide whether a fired diagnostic is real or a false positive.

Fires when useQuery|useInfiniteQuery|useSuspenseQuery|useSuspenseInfiniteQuery({ queryFn }) defines queryFn as a function with a literally empty block body — () => {} or function () {}. Concise-body arrows like () => data and any body with at least one statement are skipped, so only true placeholder/stub shapes trip the check.

Fix prompt

Use this once validation confirms the diagnostic is real.

Either return the fetched value from queryFn, or remove the property and gate the query with enabled: Boolean(id). Returning undefined caches undefined and freezes the loading state; enabled keeps the query pending without polluting the cache with bad data. https://tanstack.com/query/latest/docs/framework/react/guides/disabling-queries

Related rules

More TanStack Query rules from the rules reference:

• react-doctor/query-stable-query-client: Move `new QueryClient()` to module scope or wrap in `useState(() => new QueryClient())` — recreating it on every render resets the entire cache
• react-doctor/query-destructure-result: Destructure the query result instead of binding the whole object: const { data, isLoading } = useQuery(...)
• react-doctor/query-mutation-missing-invalidation: Add `onSuccess: () => queryClient.invalidateQueries({ queryKey: ['...'] })` so cached data stays in sync after the mutation
• react-doctor/query-no-query-in-effect: React Query manages refetching automatically via queryKey dependencies and the `enabled` option — manual refetch() in useEffect is usually unnecessary
• react-doctor/query-no-rest-destructuring: Destructure only the fields you need: `const { data, isLoading } = useQuery(...)` — rest destructuring subscribes to all fields and causes extra re-renders