Need some help about useFetch usage

export const useItemStore = defineStore('items', () => {
  const lang = computed(() => {return useCookieLocale().value})
  const {data: items, refresh} = useFetch(
    `some url`,
    {
      method: 'GET',
      params: {
        lang: lang,
        limit: 25000
      },
      headers: { 'Content-Type': 'application/json' },
      key: "items",
      server: false,
      lazy: true,
      immediate: false,
      deep: false,
      transform(raw_items:Item[]) {
        console.log({step: 'transform',  data: raw_items})
        return new Map(
          raw_items.map(raw_item => {
            return [raw_item.id, raw_item];
          }),)
      },
      getCachedData(key) {
        if (localStorage.hasOwnProperty(key)) {
          const buffer = JSON.parse(localStorage.getItem(key))
          console.log({step: 'buffer',  data: buffer})
          return buffer
        }
      },
      onResponse({ request, response, options }) {
        console.log({step: 'resp',  data: response._data})
        localStorage.setItem('items', JSON.stringify(response._data))
        return response._data
      },
    },
  )

  async function clear_cache() {
    localStorage.removeItem('items')
    await refresh()
  }

  onHydrated(async () => {
    await refresh();
  })

  return {items, clear_cache}
})

if (import.meta.hot) {
  import.meta.hot.accept(acceptHMRUpdate(useItemStore, import.meta.hot))
}