How to avoid duplicate API requests from both Server and Client sides using the @tanstack/vue-query package in Vue?

[Danny-Tseng]

I recently took over a project where the frontend uses the @tanstack/vue-query package to send API requests to the backend. How can I avoid duplicate API requests from both the Server and Client sides?

I asked Copilot, and the answer provided was as follows:

Vue Query's caching mechanism can effectively avoid duplicate API calls from the server and client sides through the following aspects:

1. Caching Data: When you use useQuery to fetch data, Vue Query automatically caches the returned data. This means that subsequent queries with the same query key will fetch data directly from the cache instead of sending a new API request.

2. Stale Time: You can set the stale time for the data. During this period, the data is considered fresh and will not be refetched. This helps avoid duplicate API requests within a short time frame.

   const { data } = useQuery('todos', fetchTodos, {
   staleTime: 1000 * 60 * 5, // Set stale time to 5 minutes
   })

3. Initial Data: In server-side rendering (SSR), you can use initialData to provide initial data, so the client does not need to send an API request again during the initial render.
   const { data } = useQuery('todos', fetchTodos, {
   initialData: serverData, // Initial data from the server
   })

4. Query Key: Each query has a unique query key that identifies and manages cached data. When the same query key is used, Vue Query will reuse the cached data instead of sending a new request.

5. Background Refetching: When data becomes stale or needs updating, Vue Query will automatically refetch the data in the background without affecting the user experience. This ensures that users see the latest data while avoiding unnecessary duplicate requests.

However, according to the official caching guide (https://tanstack.com/query/latest/docs/framework/vue/guides/caching), it seems that only setting the staleTime prevents duplicate API requests within the specified time range.

So, is it the caching mechanism of Vue Query itself, or is it only the staleTime, or are there other mechanisms to avoid duplicate API requests from both the Server and Client sides?

Thanks!

[DamianOsipiuk]

https://tanstack.com/query/latest/docs/framework/vue/guides/ssr#staleness-is-measured-from-when-the-query-was-fetched-on-the-server

A query is considered stale depending on when it was dataUpdatedAt. A caveat here is that the server needs to have the correct time for
this to work properly, but UTC time is used, so timezones do not factor into this.
Because staleTime defaults to 0, queries will be refetched in the background on page load by default. You might want to use a higher
staleTime to avoid this double fetching, especially if you don't cache your markup.