Show & Tell: tanstack-fetch — a typed fetch client shaped for queryFn (typed errors, single-flight refresh, SSE with auth)

[mohamadgarmabi]

Hi all 👋

I kept writing the same glue around axios / ky / fetch in every TanStack Query project, so I turned it into a small library: tanstack-fetch (MIT, not an official TanStack package).

The goal is to match the queryFn contract exactly: return data, throw on failure, honor the AbortSignal.

const api = createFetch({
  baseUrl: '/api',
  interceptors: [
    createAuthInterceptor({ getToken: () => accessToken }),
    createStatusInterceptor({ 401: () => logout() }),
  ],
})

useQuery({
  queryKey: ['users'],
  queryFn: ({ signal }) => api.get<User[]>('/users', { signal }),
})

What's in it

• Typed FetchError (status, body) + isFetchError for narrowing error in components
• Refresh-token interceptor with single-flight (parallel 401s → one refresh), optional proactive refresh before expiry
• SSR cookie forwarding for Next.js / Nuxt / TanStack Start
• SSE that can send an Authorization header, plus WebSocket / NDJSON streams and useSse / useWs
• Bindings for React, Vue/Nuxt, Solid, Svelte, Angular, a tRPC link, and a small DevTools request dock
• 3.57KB gzip core; everything else is opt-in

Docs & live playground: https://mohamadgarmabi.github.io/tanstack-fetch/

I'd really appreciate feedback, especially on whether the API feels natural next to Query, and anything you'd expect a Query-focused fetch client to handle that's missing.