Specifying placeholder or initial data should give data prop a different type

[midzdotdev]

Describe the bug
This bug is solely for the benefit of using react-query with TypeScript.

When specifying the initialData option, I don't think the data prop should be unioned with undefined. Then whenever you want to use the data of the returned object, you have to apply the non-null assertion operator (!) to use it's value.

I assume this also applies to placeholderData but I've not used it so not 100% here.

To Reproduce
Make a call to the useQuery hook with specifying either initialData or placeholderData.

Expected behavior
When either initialData or placeholderData is specified, then data is not unioned with undefined.

[TkDodo]

this is similar to #2306, and the answer is also the same:

• It's very hard to make that happen on type level
• queries can also be disabled, in which case status is idle and data is undefined
• every setting can be set globally in the QueryClientProvider or via queryClient.setQueryDefaults.

I actually thought "how hard can it be" and wanted to take a quick stab, but imo it would mean introducing many more generics. For what it's worth, you don't need the non-null assertion operator, you can use optional chaining.