eth_scanner•8mo ago

My TRPC hooks are getting typed as `any`

I'm using a Typescript + Express backend (Node.js, version 18), and a React Native (Typescript) frontend. For some reason by TRPC tanstack-query hooks don't seem to be typing things correctly. I am trying to understand why. I have a monorepo setup with a file structure like this: root -frontend -backend So the frontend and backend files can import from each other, and everything lives under one .git in the root. In my backend, I create a router and export the type:

const appRouter = router({
  myName1: myRouter1,
  myName2: myRouter2,
});

export type AppRouter = typeof appRouter;

const appRouter = router({
  myName1: myRouter1,
  myName2: myRouter2,
});

export type AppRouter = typeof appRouter;

Here is an example typing I get when I hover over a procedure in one of my subrouters. I don't return any in any of my procedures.

const myProcedureName: QueryProcedure<{
    input: number;
    output: ({
        author: {
            id: number;
        };
    } & {
        myDataField: number;
    })[];
}>

const myProcedureName: QueryProcedure<{
    input: number;
    output: ({
        author: {
            id: number;
        };
    } & {
        myDataField: number;
    })[];
}>

In my React Native app, I import the type:

import {createTRPCReact} from '@trpc/react-query';
import type {AppRouter} from 'my/file/path/to/backend';
export const trpc = createTRPCReact<AppRouter>();

import {createTRPCReact} from '@trpc/react-query';
import type {AppRouter} from 'my/file/path/to/backend';
export const trpc = createTRPCReact<AppRouter>();

Then in my App.tsx, I create the trpcClient:

const trpcClient = trpc.createClient({
  links: [
    httpBatchLink({
      url: `${API_URL}/trpc`,
    }),
  ],
});

const trpcClient = trpc.createClient({
  links: [
    httpBatchLink({
      url: `${API_URL}/trpc`,
    }),
  ],
});

Now when I use a hook:

// useProfile.ts
export default function useProfile(id: number) {
  return trpc.user.myProcedureName.useQuery(id);
}

//MyComponent.ts
function Component() {
  const {data} = useProfile(id);

// useProfile.ts
export default function useProfile(id: number) {
  return trpc.user.myProcedureName.useQuery(id);
}

//MyComponent.ts
function Component() {
  const {data} = useProfile(id);

My data gets typed as any, what am I doing wrong in my setup?

5 Replies

eth_scannerOP•8mo ago

I've managed to distill the issue even further: When I make this procedure on the backend:

const getPostsByUser = protectedProcedure
  .input(z.number())
  .query(async ({ input: targetId, ctx }) => {
    return "HELLO" as const;
});

const getPostsByUser = protectedProcedure
  .input(z.number())
  .query(async ({ input: targetId, ctx }) => {
    return "HELLO" as const;
});

Then my frontend hook data field gets typed correctly. But if I use a prisma query:

const getPostsByUser = protectedProcedure
  .input(z.number())
  .query(async ({ input: targetId, ctx }) => {
    return await myPrismaQuery();
});

const getPostsByUser = protectedProcedure
  .input(z.number())
  .query(async ({ input: targetId, ctx }) => {
    return await myPrismaQuery();
});

My frontend hook data field gets typed as any. Why is this happening? My prisma query is certainly not returning type any.

eth_scannerOP•8mo ago

Here is an image of the return type of my prisma query.

eth_scannerOP•8mo ago

What's even weirder is if I cast the return type:

const record = await myPrismaQuery();
return record as number; // invalid cast

const record = await myPrismaQuery();
return record as number; // invalid cast

Then my frontend data gets typed correctly as number | undefined. But if I remove the cast, turning it into the typing as pictured above, then the frontend starts getting any.

eth_scannerOP•8mo ago

I got it fixed by following this four year old twitter thread: https://x.com/colinhacks/status/1298030688063561728?lang=en

Colin McDonnell (@colinhacks) on X

"nohoist" is literally not documented anywhere except in the blog post where it was introduced https://t.co/SuobFbSq4z

Twitter

eth_scannerOP•8mo ago

Is there a reason this isn't listed in the docs anywhere (or did I miss it?). It seems like it should be a pretty common issue given how prevalent prisma is. I get it isn't an issue with TRPC per se, but it does seem like it could have a useful place here. I'd be happy to make a docs contribution.

My TRPC hooks are getting typed as `any`

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