[Sveltekit] prefetchQuery fails to cache if `url` object is accessed inside `layout.ts`

[maisonsmd]

Describe the bug

This is kinda weird and oddly specific issue, in layout.ts, if I access the url object from the load() arguments, prefetchQuery fails to cache the result.

If I comment out the access statement, everything works fine.

Your minimal, reproducible example

https://codesandbox.io/p/github/maisonsmd/tanstack-sveltequery-prefetch-issue/main?import=true

Steps to reproduce

1. Run project
2. Check prefetchQuery (page.ts) function Case A. Hover on post list's items Case B. Click on a post
3. Check network tab and Query Devtool for cache

Expected behavior

Case A

Expect: Only 1 API call needed per post, the response is cached Actual: the response is not cached, re-hovering on the same item fetches the API again.

Case B

Expect: Only 1 API call needed per post, the response is cached, clicking on the post does not result in additional API call. Actual: API is called 2 times per post as the result of failing to cache the previous call.

How often does this bug happen?

Every time

Screenshots or Videos

https://github.com/user-attachments/assets/7f5dd419-ab6e-4311-a313-986a6d3d16e8

Platform

OS: Windows 11 Pro 23H2 build 22631.4317 Browser: Microsoft Edge 129.0.2792.89 (64-bit)

Tanstack Query adapter

svelte-query

TanStack Query version

v5.59.13

TypeScript version

v5.3.3

Additional context

staleTime was set to 60 seconds.