hagabaka•16mo ago

Typed wrappers for procedures

I have a TRPC client with working queries and mutations. I wanted to create wrapper functions for all the procedure so that instead of trpc.someQuery.query(...) I can use someQuery(...), and instead of trpc.someMutation.mutate(...), someMutation(...). I'm having trouble with getting the wrapped functions to have correct parameter and return types. Currently I have:

function wrap<F extends ((...args: any[]) => any)>(fnWithClient: (c: typeof client) => F): (...args: Parameters<F>) => ReturnType<F> {
  return (...args: Parameters<F>) => fnWithClient(getClient())(...args);
}
export const someQuery = wrap((client) => client.someQuery.query)
export const someMutation = wrap((client) => client.someMutation.mutation)

function wrap<F extends ((...args: any[]) => any)>(fnWithClient: (c: typeof client) => F): (...args: Parameters<F>) => ReturnType<F> {
  return (...args: Parameters<F>) => fnWithClient(getClient())(...args);
}
export const someQuery = wrap((client) => client.someQuery.query)
export const someMutation = wrap((client) => client.someMutation.mutation)

It works in run time, and even shows correct types in VSCode, but when I generate a .d.ts, it says these functions have type (input?: unknown, options?: ProcedureOptions | undefined) => Promise<unknown>. How can I fix this issue, and is there a more elegant way to create such wrapper functions? I would prefer to use something like export const someQuery = wrap('someQuery').

9 Replies

trash•16mo ago

i wonder if this is what happens when you try to leverage types that are internal to the package, i have tried myself though tbh @julius does that sound right? just guessing

julius•16mo ago

Maybe you can get some inspiration from the withQuery() I did for cal.com https://github.com/calcom/cal.com/blob/446c29dd9c576103d7b3caa02317a65b43db0e9d/apps/web/lib/QueryCell.tsx#L86

GitHub

cal.com/QueryCell.tsx at 446c29dd9c576103d7b3caa02317a65b43db0e9d ·...

Scheduling infrastructure for absolutely everyone. - cal.com/QueryCell.tsx at 446c29dd9c576103d7b3caa02317a65b43db0e9d · calcom/cal.com

hagabaka•16mo ago

Would AnyQueryProcedure include the type of trpc.someQuery?

hagabaka•16mo ago

I don't understand DecorateQuery used in that function. Seems to be this gigantic type defined here https://github.com/trpc/trpc/blob/19c7c27d8ed548b2bc7ab5eb921fd179143aa230/packages/react-query/src/createTRPCReact.tsx#L87

GitHub

trpc/createTRPCReact.tsx at 19c7c27d8ed548b2bc7ab5eb921fd179143aa23...

🧙‍♀️ Move Fast and Break Nothing. End-to-end typesafe APIs made easy. - trpc/createTRPCReact.tsx at 19c7c27d8ed548b2bc7ab5eb921fd179143aa230 · trpc/trpc

julius•16mo ago

DecorateProcedure is the type of like trpc.post.byId yes you're extending AnyProcedure - it will get narrowed on invocation

hagabaka•16mo ago

When I try to assign const a: AnyQueryProcedure = client.someQuery, it says it is missing properties _def, _type, and _procedure I'm justing createTRPCProxyClient, not the with react

julius•16mo ago

so there's a similar type for the vanilla client - so that shouldn't be a problem why are you giving it the type implicitely? also - can you tell a bit more about the usecase? why do you want to do this?

const query = wrap(c => c.post.byId);
const data = query({ id: 1 });

const query = wrap(c => c.post.byId);
const data = query({ id: 1 });

hagabaka•16mo ago

I have a mini library that used to have only functions that make fetch calls, and now I'm adding an TRPC API. I want to keep the exports consistent so prefer to export functions for the individual procedures instead of a TRPC client. Also I want the client to be lazily created when any of the procedures is used.

Nick•16mo ago

Isn't this basically it?

function makeWrap<T>(t: T) {
  return function wrap<Q>(func: (t: T) => Q) {
    return func(t)
  }
}

const wrap = makeWrap(trpcClient)
const someId = 1
wrap(c => c.post.byId.query(someId))

function makeWrap<T>(t: T) {
  return function wrap<Q>(func: (t: T) => Q) {
    return func(t)
  }
}

const wrap = makeWrap(trpcClient)
const someId = 1
wrap(c => c.post.byId.query(someId))

Not exactly sure what's to be gained by using tRPC types in the implementation here, it would be useful to see a more complete example so we can advise