isLoading resolves data as undefined

[liel-almog]

Describe the bug

If fetching a query and then checking for isError and isLoading and return if either, the data keyword can still be undefined while isLoading is the same as isFetching && isPending according to the docs.
So if you add an and operation it still needs to be defined.

Your minimal, reproducible example

https://codesandbox.io/p/sandbox/msy6g5?file=%2Fsrc%2FApp.tsx%3A23%2C30

Steps to reproduce

Hover the type inference.

Expected behavior

The type should not have undefined

How often does this bug happen?

Every time

Screenshots or Videos

No response

Platform

Linux

Tanstack Query adapter

react-query

TanStack Query version

5.69.0

TypeScript version

5.7.2

Additional context

No response

[TkDodo]

that’s on purpose. if you want type narrowing, you need to check for isPending