queryClient.getQueryData() and queryClient.setQueryData should accept a string array

[nicemelbs]

const newNoteMutation = useMutation({
    mutationFn: createNote,

    onSuccess: (newNote) => {
      const notes = queryClient.getQueryData('notes')
      queryClient.setQueryData('notes', notes.concat(newNote))
    }
  })

In the lesson part 6d - Optimizing the Performance, and the provided code, 'notes' is passed as a string to const notes = queryClient.getQueryData('notes'), making notes equal to null. Creating a new note through the form saves it to db.json but the page doesn't get updated with the new entry.

If instead both queryClient.setQueryData and .getQueryData were given ['notes'], the page updates like it is described in the lesson.