Imagine the following pattern:

I have hooks such as useFetchTrendingPostsQuery, useFetchFeaturedPostsQuery, useFetchTechnologyPostsQuery, etc... which all return different entities of the same type.

I have a Post component, which I want to accept only a postId prop.

There is a useFetchPostQuery which would accept a postId param and fetch a single post.

However, I don't want to trigger this query if the post has already been fetched by one of: useFetchTrendingPostsQuery, useFetchFeaturedPostsQuery, useFetchTechnologyPostsQuery.

I can't really use selectFromResult, because Post is a generic component and it would have to check all of the different api queries for different types of posts.

I think I could use extraReducers to put the results from the various query hooks for different types of posts into a single store slice called posts and check that, but that feels like it defats the point of having rtk-query?

One thing I could do is provide tags from the results of those queries, such as:

fetchFeaturedPosts: builder.query({
      providesTags: data => {
          return data.map(i => ({ type: 'post', id: i.id }));
      },
      query: fetchFeaturedPostsQuery
}),
fetchTrendingPosts: builder.query({
      providesTags: data => {
          return data.map(i => ({ type: 'post', id: i.id }));
      },
      query: fetchTrendingPostsQuery
}),
fetchPost: builder.query({
      providesTags: (data, error, arg) => {
          return [{ type: 'post', id: arg.postId }];
      },
      query: fetchPost
}),

I would just need a way to link the {type: 'post', id: postId } tag back to useFetchPost in a way that would make it avoid fetching that specific post if the postId matched.

Essentially, RTK-Query is a document cache by default, but via tags I think user's could have a handy way to manually create normalized relationships between the different queries by processing the data results in providesTags.