What to do instead of loading a model with createMemo inside a createResource computation

/* solidjs view model */
function BookModel(id: string, name: string): BookModel {
  const [name, set_name] = createSignal('')
  const [chapters, set_chapters] = createSignal([])
  const nb_chapters = createMemo(() => chapters().length)
  return {nb_chapters}
}
async function db_load_book(book_id: string) {
  const mock_db = {}
  let e_book = mock_db.books.find
  let res = BookModel(e_book.id, e_book.name)
  let e_chapters = db.chapters.find
  let chapters = e_chapters
  res.set_chapters(chapters)
  return res
}
function ViewComponent() {
  let [book] = createResource(() => db_load_book('book_id1'))
  return (<>
    book()?.nb_chapters()
  </>)
}

/* solidjs view model */
function BookModel(id: string, name: string): BookModel {
  const [name, set_name] = createSignal('')
  const [chapters, set_chapters] = createSignal([])
  const nb_chapters = createMemo(() => chapters().length)
  return {nb_chapters}
}
async function db_load_book(book_id: string) {
  const mock_db = {}
  let e_book = mock_db.books.find
  let res = BookModel(e_book.id, e_book.name)
  let e_chapters = db.chapters.find
  let chapters = e_chapters
  res.set_chapters(chapters)
  return res
}
function ViewComponent() {
  let [book] = createResource(() => db_load_book('book_id1'))
  return (<>
    book()?.nb_chapters()
  </>)
}

   computations created outside a `createRoot` or `render` will never be disposed
   

   computations created outside a `createRoot` or `render` will never be disposed