NazN
tRPC•3y ago•
1 reply
Naz

How to properly type function arguments for procedures?

I'm using tRPC 10 with trpc/react-query

I'm trying to understand how to create a function that receives a procedure and it's input as arguments, so that I can then use that procedure reference to call 
useQuery
 and getQueryKey within the function:

function useUserSubscription(input: RouterInputs['collection']['user']['list']) {
  // these are the only two things that are different between subscriptions
  // and I would really like to make this a more abstract function but i have
  // NO CLUE how to type `proc` properly so it works with `getQueryKey`
  const proc = trpc.collection.user.list
  const subProc = trpc.collection.user.subscribe

  const queryClient = useQueryClient()
  const queryKey = getQueryKey(proc, input, 'query')
  const query = proc.useQuery(input)
  type Output = (typeof query)['data']

  subProc.useSubscription(
    {
      companyId: '657e3e34e2d4aa86eb145842',
    },
    {
      onData(event) {
        // Optimistically update cache
        queryClient.setQueryData<Output>(queryKey, (oldData) => {
          return handleSubscription(event, oldData) as Output
        })
      },
    }
  )

  return query
}


I'm trying to create a generic useSubscription hook. I want the useSubscription function signature to take in the procedure and it's input, but properly typed.

I've tried approaches like:

function useSubscription<TProcedure extends AnyQueryProcedure>(procedure: TProcedure, input: RouterInputs[TProcedure]) {
   const queryKey = getQueryKey(procedure)
}


But this fails for a number of reasons. The RouterInputs lookup fails because it only supports the top-level routes in my router. Can I access a flat tree of types for inputs?

getQueryKey also doesn't like taking in TProcedure when its typed as AnyQueryProcedure, the type errors suggest that it wants a decorated version, but I can't figure out how to type it properly.

Any help would be greatly appreciated.
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