createServerData$ runs twice

[viridia]

I wanted to add a 'viewCount' to my app showing the number of times a given thread was viewed. The approach I took was to update the database when fetching the list of messages in createServerData$:

export function routeData({ params }) {
  return createServerData$(
    async ([, id], { request }) => {
      const session = await getServerSession(request);
      await runQuery<{ thread: Post }>({
        operationName: 'BumpCount',
        query: threadQuery,
        session,
        variables: {
          postId: Number(id),
        },
      });
      return runQuery<{ thread: Post }>({
        operationName: 'ThreadQuery',
        query: threadQuery,
        session,
        variables: {
          postId: Number(id),
        },
      });
    },
    { key: () => ['thread', params.postId] }
  );
}

The problem I have, however, is that this code runs twice for every page that is rendered, which means that the view count gets bumped by 2.

It seems really inefficient to be double-fetching records from the database. The 'ThreadQuery' is a particularly expensive query because it's fetching an entire thread (including all the user reactions and comments), and it doesn't make much sense to fetch the data twice.

[ghalle]

Seems like the fetcher is being re-executed on the client even though the key is the same. This only happens when createRouteData is used with a function as the key. This does not happen when using a static key or when using a function key with createResource. https://stackblitz.com/edit/create-route-data-fn-key-bug?file=src%2Froutes%2Findex.tsx