Feature Request - Improve typings when passing initialData

[iway1]

Any chance we could get the type of data to not be undefined in cases where we pass initialData? we're more or less guaranteed the cache will have data in these cases right and it'd make it easier to code with if we could have type of .data just be whatever type is returned from the query function I think.

This would make it a lot easier to handle the typings when doing SSR specifically:

const Page = ({posts})=>{
  const query = useQuery({
    initialData: posts
  }) 
  query.data // this is typeof posts | undefined, why not just typeof posts?
}

[TkDodo]

that was contributed some time ago - we have tests for this:

query/packages/react-query/src/__tests__/useQuery.types.test.tsx

Lines 7 to 24 in 9be63f4

	it('TData should always be defined when initialData is provided as an object', () => {
	doNotExecute(() => {
	const { data } = useQuery({
	queryKey: ['key'],
	queryFn: () => {
	return {
	wow: true,
	}
	},
	initialData: {
	wow: true,
	},
	})
	const result: Expect<Equal<{ wow: boolean }, typeof data>> = true
	return result
	})
	})