Inconsistent Typescript behavior

[mauzybwy]

I have two projects, both using @tanstack/react-query@15.18.0 with typescript@5.3.3, however Typescript is inferring types differently.

Take the following example:

const { data } = useQuery({
  queryKey: ["test"],
  queryFn: () => Promise.resolve(5),
});

Project A correctly reports const data: number | undefined, while project B reports const data: number. Does anybody have insight into this issue?

[TkDodo]

different tsconfig settings for strict mode ?

[mauzybwy]

Yes, forgot to update question when I figured that out. But that was indeed the issue.