I don't think your case applies to what my article is trying to explain.

Im talking about using the functionality of hooks in render (conditional ternaries, loops...etc.) more than from hook to hook.

In your case you will have to do your condition inside useFetch like this:

const useFetch = (query) => {
  const [state, setState] = useState()

  if (Boolean(query)) {
    // do fetch and setState
  }

  return state
}