can I get the cached data in fetcher, or access data inside fetcher?

[sophister]

hi guys, I'm using swr for global state management. And in my situation, I want the fetcher to request API under certain conditions, which is stored in its corresponding data, see below:

function useTaskData() {
const cacheKey = 'api_generateStatus';
const {
    cache,
  } = useSWRConfig();
const {
    data,
    mutate,
} = useSWR(cacheKey, async function(){
   // here I want to read the cache. But the `currentData` got from cache, is not what I put saved
  const currentData = cache.get(cacheKey)?.data || null;
  if (currentData && currentData.task_id) {
       // request api
  } else {
      return null;
   }
}, {
    fallbackData: null,
    refreshInterval(data) {
      if (data && data.task_id) {
    // if we have a task_id, then start auto refresh interval
        return 1000;
      }
      return 0;
    },
});

return {
    data,
    mutate,
};
}

and in some other components, I will call mutate to update the data, triggering the auto refresh interval.

const {
    mutate,
} = useTaskData();
function onSubmit(){
    mutate({
       task_id: xxx,
   })
}

<button onClick={onSubmit}>submit</button>

my questions are:

1. how can we access data in cache inside the fetcher function?
2. it seems the data got from cache.get(someKey) is not the same as we return in fetcher
3. how can we read the current data inside the fetcher function (this is similar to the 1st question)

any suggestions are appreciated, thx in advance.