How do contextual queries work

[gavinthomas-valtech]

Confused slightly about contextual queries. How do they work, whats the use case? to me they look the same as using a nested object. how does it compare to standard react query?

[lukemorales]

@gavinthomas-valtech the idea is that sometimes you application might have queries that have a "parent context".

Example

You have an API call: api.com/users/:userId/favorites/:favoriteId, so in order to make that request, you need both userId and favoriteId, so you would create a nested config in your usersKeys.contextualQueries:

const usersKeys = createQueryKeys('users', {
      detail: (userId: string) => ({
        queryKey: [userId],
        queryFn: () => Promise.resolve({ id: userId }),
        contextQueries: {
          favorite:(favoriteId: string) => { ... },
        },
      }),
    });

That way, you can use in useQuery:

useQuery(usersKeys.detail(userId)._ctx.favorite(favoriteId))

[gavinthomas-valtech]

ah.. So it's not actually making the dependant query. only that you have to have made a detail userQuery first to retreive userId

[gavinthomas-valtech]

BTW. is there a codesandbox example? COuld have sworn i saw the pet client one showing contextual queries