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미들웨어

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t.procedure.use() 메서드를 사용해 프로시저에 미들웨어를 추가할 수 있습니다. 미들웨어는 프로시저 호출을 래핑하며 반드시 반환 값을 전달해야 합니다.

인증​

아래 예제에서 adminProcedure를 호출할 때는 실행 전 사용자가 "admin"인지 확인합니다.

ts
import { TRPCError, initTRPC } from '@trpc/server';
 
interface Context {
  user?: {
    id: string;
    isAdmin: boolean;
    // [..]
  };
}
 
const t = initTRPC.context<Context>().create();
export const publicProcedure = t.procedure;
export const router = t.router;
 
export const adminProcedure = publicProcedure.use(async (opts) => {
  const { ctx } = opts;
  if (!ctx.user?.isAdmin) {
    throw new TRPCError({ code: 'UNAUTHORIZED' });
  }
  return opts.next({
    ctx: {
      user: ctx.user,
    },
  });
});
ts
import { TRPCError, initTRPC } from '@trpc/server';
 
interface Context {
  user?: {
    id: string;
    isAdmin: boolean;
    // [..]
  };
}
 
const t = initTRPC.context<Context>().create();
export const publicProcedure = t.procedure;
export const router = t.router;
 
export const adminProcedure = publicProcedure.use(async (opts) => {
  const { ctx } = opts;
  if (!ctx.user?.isAdmin) {
    throw new TRPCError({ code: 'UNAUTHORIZED' });
  }
  return opts.next({
    ctx: {
      user: ctx.user,
    },
  });
});
ts
import { adminProcedure, publicProcedure, router } from './trpc';
 
const adminRouter = router({
  secretPlace: adminProcedure.query(() => 'a key'),
});
 
export const appRouter = router({
  foo: publicProcedure.query(() => 'bar'),
  admin: adminRouter,
});
ts
import { adminProcedure, publicProcedure, router } from './trpc';
 
const adminRouter = router({
  secretPlace: adminProcedure.query(() => 'a key'),
});
 
export const appRouter = router({
  foo: publicProcedure.query(() => 'bar'),
  admin: adminRouter,
});
팁

위 예제에서 발생하는 TRPCError에 대해 자세히 알아보려면 오류 처리 문서를 참조하세요.

로깅​

아래 예제에서는 쿼리 실행 시간이 자동으로 기록됩니다.

ts
export const loggedProcedure = publicProcedure.use(async (opts) => {
  const start = Date.now();
 
  const result = await opts.next();
 
  const durationMs = Date.now() - start;
  const meta = { path: opts.path, type: opts.type, durationMs };
 
  result.ok
    ? console.log('OK request timing:', meta)
    : console.error('Non-OK request timing', meta);
 
  return result;
});
ts
export const loggedProcedure = publicProcedure.use(async (opts) => {
  const start = Date.now();
 
  const result = await opts.next();
 
  const durationMs = Date.now() - start;
  const meta = { path: opts.path, type: opts.type, durationMs };
 
  result.ok
    ? console.log('OK request timing:', meta)
    : console.error('Non-OK request timing', meta);
 
  return result;
});
ts
import { loggedProcedure, router } from './trpc';
 
export const appRouter = router({
  foo: loggedProcedure.query(() => 'bar'),
  abc: loggedProcedure.query(() => 'def'),
});
ts
import { loggedProcedure, router } from './trpc';
 
export const appRouter = router({
  foo: loggedProcedure.query(() => 'bar'),
  abc: loggedProcedure.query(() => 'def'),
});

컨텍스트 확장​

"컨텍스트 확장"을 통해 미들웨어는 타입 안전한 방식으로 기본 프로시저 컨텍스트의 키를 동적으로 추가하거나 재정의할 수 있습니다.

다음은 컨텍스트 속성을 변경하는 미들웨어 예시로, 변경 사항은 다른 미들웨어나 프로시저 같은 체인된 모든 소비자가 사용할 수 있습니다:

ts
type Context = {
  // user is nullable
  user?: {
    id: string;
  };
};
 
const protectedProcedure = publicProcedure.use(async function isAuthed(opts) {
  const { ctx } = opts;
  // `ctx.user` is nullable
  if (!ctx.user) {
            
(property) user: {
    id: string;
} | undefined
    throw new TRPCError({ code: 'UNAUTHORIZED' });
  }
 
  return opts.next({
    ctx: {
      // ✅ user value is known to be non-null now
      user: ctx.user,
       
(property) user: {
    id: string;
}
    },
  });
});
 
protectedProcedure.query(({ ctx }) => ctx.user);
                                           
(property) user: {
    id: string;
}
ts
type Context = {
  // user is nullable
  user?: {
    id: string;
  };
};
 
const protectedProcedure = publicProcedure.use(async function isAuthed(opts) {
  const { ctx } = opts;
  // `ctx.user` is nullable
  if (!ctx.user) {
            
(property) user: {
    id: string;
} | undefined
    throw new TRPCError({ code: 'UNAUTHORIZED' });
  }
 
  return opts.next({
    ctx: {
      // ✅ user value is known to be non-null now
      user: ctx.user,
       
(property) user: {
    id: string;
}
    },
  });
});
 
protectedProcedure.query(({ ctx }) => ctx.user);
                                           
(property) user: {
    id: string;
}

미들웨어 확장​

정보

이 API는 새로운 기능이므로 unstable_ 접두사를 붙였지만 안전하게 사용하셔도 됩니다! 자세히 알아보기.

.pipe()라는 강력한 기능을 통해 타입 안전한 방식으로 미들웨어를 확장할 수 있습니다.

다음은 기본 미들웨어(foo)를 확장하는 미들웨어 예시입니다. 앞서 살펴본 컨텍스트 확장 예시와 마찬가지로, 미들웨어를 파이핑하면 컨텍스트 속성이 변경되며 프로시저는 새로운 컨텍스트 값을 수신합니다.

ts
const fooMiddleware = t.middleware((opts) => {
  return opts.next({
    ctx: {
      foo: 'foo' as const,
    },
  });
});
 
const barMiddleware = fooMiddleware.unstable_pipe((opts) => {
  const { ctx } = opts;
  ctx.foo;
      
(property) foo: "foo"
  return opts.next({
    ctx: {
      bar: 'bar' as const,
    },
  });
});
 
const barProcedure = publicProcedure.use(barMiddleware);
barProcedure.query(({ ctx }) => ctx.bar);
                      
(parameter) ctx: {
    foo: "foo";
    bar: "bar";
}
ts
const fooMiddleware = t.middleware((opts) => {
  return opts.next({
    ctx: {
      foo: 'foo' as const,
    },
  });
});
 
const barMiddleware = fooMiddleware.unstable_pipe((opts) => {
  const { ctx } = opts;
  ctx.foo;
      
(property) foo: "foo"
  return opts.next({
    ctx: {
      bar: 'bar' as const,
    },
  });
});
 
const barProcedure = publicProcedure.use(barMiddleware);
barProcedure.query(({ ctx }) => ctx.bar);
                      
(parameter) ctx: {
    foo: "foo";
    bar: "bar";
}

미들웨어 파이핑 순서가 중요하며 컨텍스트가 반드시 중첩되어야 합니다. 아래는 허용되지 않는 파이프 예시입니다. 여기서 fooMiddleware는 ctx.a를 재정의하는 반면, barMiddleware는 initTRPC 초기화 시 설정된 루트 컨텍스트를 기대합니다. 따라서 fooMiddleware를 barMiddleware와 파이핑하면 작동하지 않으며, barMiddleware를 fooMiddleware와 파이핑하면 정상 작동합니다.

ts
import { initTRPC } from '@trpc/server';
 
const t = initTRPC
  .context<{
    a: {
      b: 'a';
    };
  }>()
  .create();
 
const fooMiddleware = t.middleware((opts) => {
  const { ctx } = opts;
  ctx.a; // 👈 fooMiddleware expects `ctx.a` to be an object
     
(property) a: {
    b: "a";
}
  return opts.next({
    ctx: {
      a: 'a' as const, // 👈 `ctx.a` is no longer an object
    },
  });
});
 
const barMiddleware = t.middleware((opts) => {
  const { ctx } = opts;
  ctx.a; // 👈 barMiddleware expects `ctx.a` to be an object
     
(property) a: {
    b: "a";
}
  return opts.next({
    ctx: {
      foo: 'foo' as const,
    },
  });
});
 
// ❌ `ctx.a` does not overlap from `fooMiddleware` to `barMiddleware`
fooMiddleware.unstable_pipe(barMiddleware);
Argument of type 'MiddlewareBuilder<{ a: { b: "a"; }; }, object, { foo: "foo"; }, unknown>' is not assignable to parameter of type 'MiddlewareFunction<{ a: { b: "a"; }; }, object, { a: "a"; }, { foo: "foo"; }, unknown> | MiddlewareBuilder<{ a: "a"; }, object, { foo: "foo"; }, unknown>'.
  Type 'MiddlewareBuilder<{ a: { b: "a"; }; }, object, { foo: "foo"; }, unknown>' is not assignable to type 'MiddlewareBuilder<{ a: "a"; }, object, { foo: "foo"; }, unknown>'.
    Types of property 'unstable_pipe' are incompatible.
      Type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ a: { b: "a"; }; }, object, { foo: "foo"; }, $ContextOverridesOut, unknown> | MiddlewareBuilder<{ a: { b: "a"; }; foo: "foo"; }, object, $ContextOverridesOut, unknown>) => MiddlewareBuilder<...>' is not assignable to type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ a: "a"; }, object, { foo: "foo"; }, $ContextOverridesOut, unknown> | MiddlewareBuilder<{ a: "a"; foo: "foo"; }, object, $ContextOverridesOut, unknown>) => MiddlewareBuilder<...>'.
        Types of parameters 'fn' and 'fn' are incompatible.
          Type 'MiddlewareFunction<{ a: "a"; }, object, { foo: "foo"; }, any, unknown> | MiddlewareBuilder<{ a: "a"; foo: "foo"; }, object, any, unknown>' is not assignable to type 'MiddlewareFunction<{ a: { b: "a"; }; }, object, { foo: "foo"; }, any, unknown> | MiddlewareBuilder<{ a: { b: "a"; }; foo: "foo"; }, object, any, unknown>'.
            Type 'MiddlewareFunction<{ a: "a"; }, object, { foo: "foo"; }, any, unknown>' is not assignable to type 'MiddlewareFunction<{ a: { b: "a"; }; }, object, { foo: "foo"; }, any, unknown> | MiddlewareBuilder<{ a: { b: "a"; }; foo: "foo"; }, object, any, unknown>'.
              Type 'MiddlewareFunction<{ a: "a"; }, object, { foo: "foo"; }, any, unknown>' is not assignable to type 'MiddlewareFunction<{ a: { b: "a"; }; }, object, { foo: "foo"; }, any, unknown>'.
                Types of parameters 'opts' and 'opts' are incompatible.
                  Type '{ ctx: { a: { b: "a"; }; foo: "foo"; }; type: "query" | "mutation" | "subscription"; path: string; input: unknown; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }' is not assignable to type '{ ctx: { a: "a"; foo: "foo"; }; type: "query" | "mutation" | "subscription"; path: string; input: unknown; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }'.
                    The types of 'ctx.a' are incompatible between these types.
                      Type '{ b: "a"; }' is not assignable to type '"a"'.2345Argument of type 'MiddlewareBuilder<{ a: { b: "a"; }; }, object, { foo: "foo"; }, unknown>' is not assignable to parameter of type 'MiddlewareFunction<{ a: { b: "a"; }; }, object, { a: "a"; }, { foo: "foo"; }, unknown> | MiddlewareBuilder<{ a: "a"; }, object, { foo: "foo"; }, unknown>'.
  Type 'MiddlewareBuilder<{ a: { b: "a"; }; }, object, { foo: "foo"; }, unknown>' is not assignable to type 'MiddlewareBuilder<{ a: "a"; }, object, { foo: "foo"; }, unknown>'.
    Types of property 'unstable_pipe' are incompatible.
      Type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ a: { b: "a"; }; }, object, { foo: "foo"; }, $ContextOverridesOut, unknown> | MiddlewareBuilder<{ a: { b: "a"; }; foo: "foo"; }, object, $ContextOverridesOut, unknown>) => MiddlewareBuilder<...>' is not assignable to type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ a: "a"; }, object, { foo: "foo"; }, $ContextOverridesOut, unknown> | MiddlewareBuilder<{ a: "a"; foo: "foo"; }, object, $ContextOverridesOut, unknown>) => MiddlewareBuilder<...>'.
        Types of parameters 'fn' and 'fn' are incompatible.
          Type 'MiddlewareFunction<{ a: "a"; }, object, { foo: "foo"; }, any, unknown> | MiddlewareBuilder<{ a: "a"; foo: "foo"; }, object, any, unknown>' is not assignable to type 'MiddlewareFunction<{ a: { b: "a"; }; }, object, { foo: "foo"; }, any, unknown> | MiddlewareBuilder<{ a: { b: "a"; }; foo: "foo"; }, object, any, unknown>'.
            Type 'MiddlewareFunction<{ a: "a"; }, object, { foo: "foo"; }, any, unknown>' is not assignable to type 'MiddlewareFunction<{ a: { b: "a"; }; }, object, { foo: "foo"; }, any, unknown> | MiddlewareBuilder<{ a: { b: "a"; }; foo: "foo"; }, object, any, unknown>'.
              Type 'MiddlewareFunction<{ a: "a"; }, object, { foo: "foo"; }, any, unknown>' is not assignable to type 'MiddlewareFunction<{ a: { b: "a"; }; }, object, { foo: "foo"; }, any, unknown>'.
                Types of parameters 'opts' and 'opts' are incompatible.
                  Type '{ ctx: { a: { b: "a"; }; foo: "foo"; }; type: "query" | "mutation" | "subscription"; path: string; input: unknown; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }' is not assignable to type '{ ctx: { a: "a"; foo: "foo"; }; type: "query" | "mutation" | "subscription"; path: string; input: unknown; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }'.
                    The types of 'ctx.a' are incompatible between these types.
                      Type '{ b: "a"; }' is not assignable to type '"a"'.
 
// ✅ `ctx.a` overlaps from `barMiddleware` and `fooMiddleware`
barMiddleware.unstable_pipe(fooMiddleware);
ts
import { initTRPC } from '@trpc/server';
 
const t = initTRPC
  .context<{
    a: {
      b: 'a';
    };
  }>()
  .create();
 
const fooMiddleware = t.middleware((opts) => {
  const { ctx } = opts;
  ctx.a; // 👈 fooMiddleware expects `ctx.a` to be an object
     
(property) a: {
    b: "a";
}
  return opts.next({
    ctx: {
      a: 'a' as const, // 👈 `ctx.a` is no longer an object
    },
  });
});
 
const barMiddleware = t.middleware((opts) => {
  const { ctx } = opts;
  ctx.a; // 👈 barMiddleware expects `ctx.a` to be an object
     
(property) a: {
    b: "a";
}
  return opts.next({
    ctx: {
      foo: 'foo' as const,
    },
  });
});
 
// ❌ `ctx.a` does not overlap from `fooMiddleware` to `barMiddleware`
fooMiddleware.unstable_pipe(barMiddleware);
Argument of type 'MiddlewareBuilder<{ a: { b: "a"; }; }, object, { foo: "foo"; }, unknown>' is not assignable to parameter of type 'MiddlewareFunction<{ a: { b: "a"; }; }, object, { a: "a"; }, { foo: "foo"; }, unknown> | MiddlewareBuilder<{ a: "a"; }, object, { foo: "foo"; }, unknown>'.
  Type 'MiddlewareBuilder<{ a: { b: "a"; }; }, object, { foo: "foo"; }, unknown>' is not assignable to type 'MiddlewareBuilder<{ a: "a"; }, object, { foo: "foo"; }, unknown>'.
    Types of property 'unstable_pipe' are incompatible.
      Type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ a: { b: "a"; }; }, object, { foo: "foo"; }, $ContextOverridesOut, unknown> | MiddlewareBuilder<{ a: { b: "a"; }; foo: "foo"; }, object, $ContextOverridesOut, unknown>) => MiddlewareBuilder<...>' is not assignable to type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ a: "a"; }, object, { foo: "foo"; }, $ContextOverridesOut, unknown> | MiddlewareBuilder<{ a: "a"; foo: "foo"; }, object, $ContextOverridesOut, unknown>) => MiddlewareBuilder<...>'.
        Types of parameters 'fn' and 'fn' are incompatible.
          Type 'MiddlewareFunction<{ a: "a"; }, object, { foo: "foo"; }, any, unknown> | MiddlewareBuilder<{ a: "a"; foo: "foo"; }, object, any, unknown>' is not assignable to type 'MiddlewareFunction<{ a: { b: "a"; }; }, object, { foo: "foo"; }, any, unknown> | MiddlewareBuilder<{ a: { b: "a"; }; foo: "foo"; }, object, any, unknown>'.
            Type 'MiddlewareFunction<{ a: "a"; }, object, { foo: "foo"; }, any, unknown>' is not assignable to type 'MiddlewareFunction<{ a: { b: "a"; }; }, object, { foo: "foo"; }, any, unknown> | MiddlewareBuilder<{ a: { b: "a"; }; foo: "foo"; }, object, any, unknown>'.
              Type 'MiddlewareFunction<{ a: "a"; }, object, { foo: "foo"; }, any, unknown>' is not assignable to type 'MiddlewareFunction<{ a: { b: "a"; }; }, object, { foo: "foo"; }, any, unknown>'.
                Types of parameters 'opts' and 'opts' are incompatible.
                  Type '{ ctx: { a: { b: "a"; }; foo: "foo"; }; type: "query" | "mutation" | "subscription"; path: string; input: unknown; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }' is not assignable to type '{ ctx: { a: "a"; foo: "foo"; }; type: "query" | "mutation" | "subscription"; path: string; input: unknown; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }'.
                    The types of 'ctx.a' are incompatible between these types.
                      Type '{ b: "a"; }' is not assignable to type '"a"'.2345Argument of type 'MiddlewareBuilder<{ a: { b: "a"; }; }, object, { foo: "foo"; }, unknown>' is not assignable to parameter of type 'MiddlewareFunction<{ a: { b: "a"; }; }, object, { a: "a"; }, { foo: "foo"; }, unknown> | MiddlewareBuilder<{ a: "a"; }, object, { foo: "foo"; }, unknown>'.
  Type 'MiddlewareBuilder<{ a: { b: "a"; }; }, object, { foo: "foo"; }, unknown>' is not assignable to type 'MiddlewareBuilder<{ a: "a"; }, object, { foo: "foo"; }, unknown>'.
    Types of property 'unstable_pipe' are incompatible.
      Type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ a: { b: "a"; }; }, object, { foo: "foo"; }, $ContextOverridesOut, unknown> | MiddlewareBuilder<{ a: { b: "a"; }; foo: "foo"; }, object, $ContextOverridesOut, unknown>) => MiddlewareBuilder<...>' is not assignable to type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ a: "a"; }, object, { foo: "foo"; }, $ContextOverridesOut, unknown> | MiddlewareBuilder<{ a: "a"; foo: "foo"; }, object, $ContextOverridesOut, unknown>) => MiddlewareBuilder<...>'.
        Types of parameters 'fn' and 'fn' are incompatible.
          Type 'MiddlewareFunction<{ a: "a"; }, object, { foo: "foo"; }, any, unknown> | MiddlewareBuilder<{ a: "a"; foo: "foo"; }, object, any, unknown>' is not assignable to type 'MiddlewareFunction<{ a: { b: "a"; }; }, object, { foo: "foo"; }, any, unknown> | MiddlewareBuilder<{ a: { b: "a"; }; foo: "foo"; }, object, any, unknown>'.
            Type 'MiddlewareFunction<{ a: "a"; }, object, { foo: "foo"; }, any, unknown>' is not assignable to type 'MiddlewareFunction<{ a: { b: "a"; }; }, object, { foo: "foo"; }, any, unknown> | MiddlewareBuilder<{ a: { b: "a"; }; foo: "foo"; }, object, any, unknown>'.
              Type 'MiddlewareFunction<{ a: "a"; }, object, { foo: "foo"; }, any, unknown>' is not assignable to type 'MiddlewareFunction<{ a: { b: "a"; }; }, object, { foo: "foo"; }, any, unknown>'.
                Types of parameters 'opts' and 'opts' are incompatible.
                  Type '{ ctx: { a: { b: "a"; }; foo: "foo"; }; type: "query" | "mutation" | "subscription"; path: string; input: unknown; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }' is not assignable to type '{ ctx: { a: "a"; foo: "foo"; }; type: "query" | "mutation" | "subscription"; path: string; input: unknown; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }'.
                    The types of 'ctx.a' are incompatible between these types.
                      Type '{ b: "a"; }' is not assignable to type '"a"'.
 
// ✅ `ctx.a` overlaps from `barMiddleware` and `fooMiddleware`
barMiddleware.unstable_pipe(fooMiddleware);

실험적 기능: 독립형 미들웨어​

정보

주의: 이 기능에는 experimental_ 접두사가 붙어 있으며, tRPC 릴리스마다 변경될 수 있습니다. 자세히 알아보기.

tRPC에는 experimental_standaloneMiddleware라는 새로운 실험적 API가 있습니다. 이를 사용하면 모든 tRPC 인스턴스와 함께 사용할 수 있는 미들웨어를 독립적으로 정의할 수 있습니다. t.middleware를 사용해 미들웨어를 생성할 때는 Context 타입이 tRPC 인스턴스의 Context 타입에 묶인다는 제약이 있습니다.
즉, Context 타입이 서로 다른 여러 tRPC 인스턴스에서 동일한 미들웨어를 사용할 수 없습니다.

experimental_standaloneMiddleware를 사용하면 Context, Input, Meta 타입 같은 요구 사항을 명시적으로 정의하는 미들웨어를 생성할 수 있습니다:

ts
import {
  experimental_standaloneMiddleware,
  initTRPC,
  TRPCError,
} from '@trpc/server';
import * as z from 'zod';
 
const projectAccessMiddleware = experimental_standaloneMiddleware<{
  ctx: { allowedProjects: string[] }; // defaults to 'object' if not defined
  input: { projectId: string }; // defaults to 'unknown' if not defined
  // 'meta', not defined here, defaults to 'object | undefined'
}>().create((opts) => {
  if (!opts.ctx.allowedProjects.includes(opts.input.projectId)) {
    throw new TRPCError({
      code: 'FORBIDDEN',
      message: 'Not allowed',
    });
  }
 
  return opts.next();
});
 
const t1 = initTRPC
  .context<{
    allowedProjects: string[];
  }>()
  .create();
 
// ✅ `ctx.allowedProjects` satisfies "string[]" and `input.projectId` satisfies "string"
const accessControlledProcedure = t1.procedure
  .input(z.object({ projectId: z.string() }))
  .use(projectAccessMiddleware);
 
// ❌ `ctx.allowedProjects` satisfies "string[]" but `input.projectId` does not satisfy "string"
const accessControlledProcedure2 = t1.procedure
  .input(z.object({ projectId: z.number() }))
  .use(projectAccessMiddleware);
Argument of type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: string; }>' is not assignable to parameter of type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: number; }> | MiddlewareFunction<{ allowedProjects: string[]; }, object, object, object, { projectId: number; }>'.
  Type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: string; }>' is not assignable to type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: number; }>'.
    Types of property 'unstable_pipe' are incompatible.
      Type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ allowedProjects: string[]; }, object, object, $ContextOverridesOut, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, $ContextOverridesOut, { ...; }>) => MiddlewareBuilder<...>' is not assignable to type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ allowedProjects: string[]; }, object, object, $ContextOverridesOut, { projectId: number; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, $ContextOverridesOut, { ...; }>) => MiddlewareBuilder<...>'.
        Types of parameters 'fn' and 'fn' are incompatible.
          Type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: number; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: number; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: string; }>'.
            Type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: number; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: string; }>'.
              Type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: number; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }>'.
                Types of parameters 'opts' and 'opts' are incompatible.
                  Type '{ ctx: { allowedProjects: string[]; }; type: "query" | "mutation" | "subscription"; path: string; input: { projectId: string; }; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }' is not assignable to type '{ ctx: { allowedProjects: string[]; }; type: "query" | "mutation" | "subscription"; path: string; input: { projectId: number; }; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }'.
                    The types of 'input.projectId' are incompatible between these types.
                      Type 'string' is not assignable to type 'number'.2345Argument of type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: string; }>' is not assignable to parameter of type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: number; }> | MiddlewareFunction<{ allowedProjects: string[]; }, object, object, object, { projectId: number; }>'.
  Type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: string; }>' is not assignable to type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: number; }>'.
    Types of property 'unstable_pipe' are incompatible.
      Type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ allowedProjects: string[]; }, object, object, $ContextOverridesOut, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, $ContextOverridesOut, { ...; }>) => MiddlewareBuilder<...>' is not assignable to type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ allowedProjects: string[]; }, object, object, $ContextOverridesOut, { projectId: number; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, $ContextOverridesOut, { ...; }>) => MiddlewareBuilder<...>'.
        Types of parameters 'fn' and 'fn' are incompatible.
          Type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: number; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: number; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: string; }>'.
            Type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: number; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: string; }>'.
              Type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: number; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }>'.
                Types of parameters 'opts' and 'opts' are incompatible.
                  Type '{ ctx: { allowedProjects: string[]; }; type: "query" | "mutation" | "subscription"; path: string; input: { projectId: string; }; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }' is not assignable to type '{ ctx: { allowedProjects: string[]; }; type: "query" | "mutation" | "subscription"; path: string; input: { projectId: number; }; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }'.
                    The types of 'input.projectId' are incompatible between these types.
                      Type 'string' is not assignable to type 'number'.
 
// ❌ `ctx.allowedProjects` does not satisfy "string[]" even though `input.projectId` satisfies "string"
const t2 = initTRPC
  .context<{
    allowedProjects: number[];
  }>()
  .create();
 
const accessControlledProcedure3 = t2.procedure
  .input(z.object({ projectId: z.string() }))
  .use(projectAccessMiddleware);
Argument of type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: string; }>' is not assignable to parameter of type 'MiddlewareBuilder<{ allowedProjects: number[]; }, object, object, { projectId: string; }> | MiddlewareFunction<{ allowedProjects: number[]; }, object, object, object, { projectId: string; }>'.
  Type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: string; }>' is not assignable to type 'MiddlewareBuilder<{ allowedProjects: number[]; }, object, object, { projectId: string; }>'.
    Types of property 'unstable_pipe' are incompatible.
      Type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ allowedProjects: string[]; }, object, object, $ContextOverridesOut, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, $ContextOverridesOut, { ...; }>) => MiddlewareBuilder<...>' is not assignable to type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ allowedProjects: number[]; }, object, object, $ContextOverridesOut, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: number[]; }, object, $ContextOverridesOut, { ...; }>) => MiddlewareBuilder<...>'.
        Types of parameters 'fn' and 'fn' are incompatible.
          Type 'MiddlewareFunction<{ allowedProjects: number[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: number[]; }, object, any, { projectId: string; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: string; }>'.
            Type 'MiddlewareFunction<{ allowedProjects: number[]; }, object, object, any, { projectId: string; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: string; }>'.
              Type 'MiddlewareFunction<{ allowedProjects: number[]; }, object, object, any, { projectId: string; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }>'.
                Types of parameters 'opts' and 'opts' are incompatible.
                  Type '{ ctx: { allowedProjects: string[]; }; type: "query" | "mutation" | "subscription"; path: string; input: { projectId: string; }; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }' is not assignable to type '{ ctx: { allowedProjects: number[]; }; type: "query" | "mutation" | "subscription"; path: string; input: { projectId: string; }; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }'.
                    The types of 'ctx.allowedProjects' are incompatible between these types.
                      Type 'string[]' is not assignable to type 'number[]'.
                        Type 'string' is not assignable to type 'number'.2345Argument of type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: string; }>' is not assignable to parameter of type 'MiddlewareBuilder<{ allowedProjects: number[]; }, object, object, { projectId: string; }> | MiddlewareFunction<{ allowedProjects: number[]; }, object, object, object, { projectId: string; }>'.
  Type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: string; }>' is not assignable to type 'MiddlewareBuilder<{ allowedProjects: number[]; }, object, object, { projectId: string; }>'.
    Types of property 'unstable_pipe' are incompatible.
      Type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ allowedProjects: string[]; }, object, object, $ContextOverridesOut, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, $ContextOverridesOut, { ...; }>) => MiddlewareBuilder<...>' is not assignable to type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ allowedProjects: number[]; }, object, object, $ContextOverridesOut, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: number[]; }, object, $ContextOverridesOut, { ...; }>) => MiddlewareBuilder<...>'.
        Types of parameters 'fn' and 'fn' are incompatible.
          Type 'MiddlewareFunction<{ allowedProjects: number[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: number[]; }, object, any, { projectId: string; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: string; }>'.
            Type 'MiddlewareFunction<{ allowedProjects: number[]; }, object, object, any, { projectId: string; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: string; }>'.
              Type 'MiddlewareFunction<{ allowedProjects: number[]; }, object, object, any, { projectId: string; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }>'.
                Types of parameters 'opts' and 'opts' are incompatible.
                  Type '{ ctx: { allowedProjects: string[]; }; type: "query" | "mutation" | "subscription"; path: string; input: { projectId: string; }; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }' is not assignable to type '{ ctx: { allowedProjects: number[]; }; type: "query" | "mutation" | "subscription"; path: string; input: { projectId: string; }; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }'.
                    The types of 'ctx.allowedProjects' are incompatible between these types.
                      Type 'string[]' is not assignable to type 'number[]'.
                        Type 'string' is not assignable to type 'number'.
ts
import {
  experimental_standaloneMiddleware,
  initTRPC,
  TRPCError,
} from '@trpc/server';
import * as z from 'zod';
 
const projectAccessMiddleware = experimental_standaloneMiddleware<{
  ctx: { allowedProjects: string[] }; // defaults to 'object' if not defined
  input: { projectId: string }; // defaults to 'unknown' if not defined
  // 'meta', not defined here, defaults to 'object | undefined'
}>().create((opts) => {
  if (!opts.ctx.allowedProjects.includes(opts.input.projectId)) {
    throw new TRPCError({
      code: 'FORBIDDEN',
      message: 'Not allowed',
    });
  }
 
  return opts.next();
});
 
const t1 = initTRPC
  .context<{
    allowedProjects: string[];
  }>()
  .create();
 
// ✅ `ctx.allowedProjects` satisfies "string[]" and `input.projectId` satisfies "string"
const accessControlledProcedure = t1.procedure
  .input(z.object({ projectId: z.string() }))
  .use(projectAccessMiddleware);
 
// ❌ `ctx.allowedProjects` satisfies "string[]" but `input.projectId` does not satisfy "string"
const accessControlledProcedure2 = t1.procedure
  .input(z.object({ projectId: z.number() }))
  .use(projectAccessMiddleware);
Argument of type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: string; }>' is not assignable to parameter of type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: number; }> | MiddlewareFunction<{ allowedProjects: string[]; }, object, object, object, { projectId: number; }>'.
  Type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: string; }>' is not assignable to type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: number; }>'.
    Types of property 'unstable_pipe' are incompatible.
      Type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ allowedProjects: string[]; }, object, object, $ContextOverridesOut, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, $ContextOverridesOut, { ...; }>) => MiddlewareBuilder<...>' is not assignable to type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ allowedProjects: string[]; }, object, object, $ContextOverridesOut, { projectId: number; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, $ContextOverridesOut, { ...; }>) => MiddlewareBuilder<...>'.
        Types of parameters 'fn' and 'fn' are incompatible.
          Type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: number; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: number; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: string; }>'.
            Type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: number; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: string; }>'.
              Type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: number; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }>'.
                Types of parameters 'opts' and 'opts' are incompatible.
                  Type '{ ctx: { allowedProjects: string[]; }; type: "query" | "mutation" | "subscription"; path: string; input: { projectId: string; }; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }' is not assignable to type '{ ctx: { allowedProjects: string[]; }; type: "query" | "mutation" | "subscription"; path: string; input: { projectId: number; }; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }'.
                    The types of 'input.projectId' are incompatible between these types.
                      Type 'string' is not assignable to type 'number'.2345Argument of type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: string; }>' is not assignable to parameter of type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: number; }> | MiddlewareFunction<{ allowedProjects: string[]; }, object, object, object, { projectId: number; }>'.
  Type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: string; }>' is not assignable to type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: number; }>'.
    Types of property 'unstable_pipe' are incompatible.
      Type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ allowedProjects: string[]; }, object, object, $ContextOverridesOut, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, $ContextOverridesOut, { ...; }>) => MiddlewareBuilder<...>' is not assignable to type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ allowedProjects: string[]; }, object, object, $ContextOverridesOut, { projectId: number; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, $ContextOverridesOut, { ...; }>) => MiddlewareBuilder<...>'.
        Types of parameters 'fn' and 'fn' are incompatible.
          Type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: number; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: number; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: string; }>'.
            Type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: number; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: string; }>'.
              Type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: number; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }>'.
                Types of parameters 'opts' and 'opts' are incompatible.
                  Type '{ ctx: { allowedProjects: string[]; }; type: "query" | "mutation" | "subscription"; path: string; input: { projectId: string; }; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }' is not assignable to type '{ ctx: { allowedProjects: string[]; }; type: "query" | "mutation" | "subscription"; path: string; input: { projectId: number; }; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }'.
                    The types of 'input.projectId' are incompatible between these types.
                      Type 'string' is not assignable to type 'number'.
 
// ❌ `ctx.allowedProjects` does not satisfy "string[]" even though `input.projectId` satisfies "string"
const t2 = initTRPC
  .context<{
    allowedProjects: number[];
  }>()
  .create();
 
const accessControlledProcedure3 = t2.procedure
  .input(z.object({ projectId: z.string() }))
  .use(projectAccessMiddleware);
Argument of type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: string; }>' is not assignable to parameter of type 'MiddlewareBuilder<{ allowedProjects: number[]; }, object, object, { projectId: string; }> | MiddlewareFunction<{ allowedProjects: number[]; }, object, object, object, { projectId: string; }>'.
  Type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: string; }>' is not assignable to type 'MiddlewareBuilder<{ allowedProjects: number[]; }, object, object, { projectId: string; }>'.
    Types of property 'unstable_pipe' are incompatible.
      Type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ allowedProjects: string[]; }, object, object, $ContextOverridesOut, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, $ContextOverridesOut, { ...; }>) => MiddlewareBuilder<...>' is not assignable to type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ allowedProjects: number[]; }, object, object, $ContextOverridesOut, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: number[]; }, object, $ContextOverridesOut, { ...; }>) => MiddlewareBuilder<...>'.
        Types of parameters 'fn' and 'fn' are incompatible.
          Type 'MiddlewareFunction<{ allowedProjects: number[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: number[]; }, object, any, { projectId: string; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: string; }>'.
            Type 'MiddlewareFunction<{ allowedProjects: number[]; }, object, object, any, { projectId: string; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: string; }>'.
              Type 'MiddlewareFunction<{ allowedProjects: number[]; }, object, object, any, { projectId: string; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }>'.
                Types of parameters 'opts' and 'opts' are incompatible.
                  Type '{ ctx: { allowedProjects: string[]; }; type: "query" | "mutation" | "subscription"; path: string; input: { projectId: string; }; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }' is not assignable to type '{ ctx: { allowedProjects: number[]; }; type: "query" | "mutation" | "subscription"; path: string; input: { projectId: string; }; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }'.
                    The types of 'ctx.allowedProjects' are incompatible between these types.
                      Type 'string[]' is not assignable to type 'number[]'.
                        Type 'string' is not assignable to type 'number'.2345Argument of type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: string; }>' is not assignable to parameter of type 'MiddlewareBuilder<{ allowedProjects: number[]; }, object, object, { projectId: string; }> | MiddlewareFunction<{ allowedProjects: number[]; }, object, object, object, { projectId: string; }>'.
  Type 'MiddlewareBuilder<{ allowedProjects: string[]; }, object, object, { projectId: string; }>' is not assignable to type 'MiddlewareBuilder<{ allowedProjects: number[]; }, object, object, { projectId: string; }>'.
    Types of property 'unstable_pipe' are incompatible.
      Type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ allowedProjects: string[]; }, object, object, $ContextOverridesOut, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, $ContextOverridesOut, { ...; }>) => MiddlewareBuilder<...>' is not assignable to type '<$ContextOverridesOut>(fn: MiddlewareFunction<{ allowedProjects: number[]; }, object, object, $ContextOverridesOut, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: number[]; }, object, $ContextOverridesOut, { ...; }>) => MiddlewareBuilder<...>'.
        Types of parameters 'fn' and 'fn' are incompatible.
          Type 'MiddlewareFunction<{ allowedProjects: number[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: number[]; }, object, any, { projectId: string; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: string; }>'.
            Type 'MiddlewareFunction<{ allowedProjects: number[]; }, object, object, any, { projectId: string; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }> | MiddlewareBuilder<{ allowedProjects: string[]; }, object, any, { projectId: string; }>'.
              Type 'MiddlewareFunction<{ allowedProjects: number[]; }, object, object, any, { projectId: string; }>' is not assignable to type 'MiddlewareFunction<{ allowedProjects: string[]; }, object, object, any, { projectId: string; }>'.
                Types of parameters 'opts' and 'opts' are incompatible.
                  Type '{ ctx: { allowedProjects: string[]; }; type: "query" | "mutation" | "subscription"; path: string; input: { projectId: string; }; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }' is not assignable to type '{ ctx: { allowedProjects: number[]; }; type: "query" | "mutation" | "subscription"; path: string; input: { projectId: string; }; getRawInput: GetRawInputFn; meta: object | undefined; signal: AbortSignal | undefined; next: { ...; }; }'.
                    The types of 'ctx.allowedProjects' are incompatible between these types.
                      Type 'string[]' is not assignable to type 'number[]'.
                        Type 'string' is not assignable to type 'number'.

다음은 여러 독립형 미들웨어를 사용한 예시입니다:

ts
import { experimental_standaloneMiddleware, initTRPC } from '@trpc/server';
import * as z from 'zod';
 
const t = initTRPC.create();
const schemaA = z.object({ valueA: z.string() });
const schemaB = z.object({ valueB: z.string() });
 
const valueAUppercaserMiddleware = experimental_standaloneMiddleware<{
  input: z.infer<typeof schemaA>;
}>().create((opts) => {
  return opts.next({
    ctx: { valueAUppercase: opts.input.valueA.toUpperCase() },
  });
});
 
const valueBUppercaserMiddleware = experimental_standaloneMiddleware<{
  input: z.infer<typeof schemaB>;
}>().create((opts) => {
  return opts.next({
    ctx: { valueBUppercase: opts.input.valueB.toUpperCase() },
  });
});
 
const combinedInputThatSatisfiesBothMiddlewares = z.object({
  valueA: z.string(),
  valueB: z.string(),
  extraProp: z.string(),
});
 
t.procedure
  .input(combinedInputThatSatisfiesBothMiddlewares)
  .use(valueAUppercaserMiddleware)
  .use(valueBUppercaserMiddleware)
  .query(
    ({
      input: { valueA, valueB, extraProp },
      ctx: { valueAUppercase, valueBUppercase },
    }) =>
      `valueA: ${valueA}, valueB: ${valueB}, extraProp: ${extraProp}, valueAUppercase: ${valueAUppercase}, valueBUppercase: ${valueBUppercase}`,
  );
ts
import { experimental_standaloneMiddleware, initTRPC } from '@trpc/server';
import * as z from 'zod';
 
const t = initTRPC.create();
const schemaA = z.object({ valueA: z.string() });
const schemaB = z.object({ valueB: z.string() });
 
const valueAUppercaserMiddleware = experimental_standaloneMiddleware<{
  input: z.infer<typeof schemaA>;
}>().create((opts) => {
  return opts.next({
    ctx: { valueAUppercase: opts.input.valueA.toUpperCase() },
  });
});
 
const valueBUppercaserMiddleware = experimental_standaloneMiddleware<{
  input: z.infer<typeof schemaB>;
}>().create((opts) => {
  return opts.next({
    ctx: { valueBUppercase: opts.input.valueB.toUpperCase() },
  });
});
 
const combinedInputThatSatisfiesBothMiddlewares = z.object({
  valueA: z.string(),
  valueB: z.string(),
  extraProp: z.string(),
});
 
t.procedure
  .input(combinedInputThatSatisfiesBothMiddlewares)
  .use(valueAUppercaserMiddleware)
  .use(valueBUppercaserMiddleware)
  .query(
    ({
      input: { valueA, valueB, extraProp },
      ctx: { valueAUppercase, valueBUppercase },
    }) =>
      `valueA: ${valueA}, valueB: ${valueB}, extraProp: ${extraProp}, valueAUppercase: ${valueAUppercase}, valueBUppercase: ${valueBUppercase}`,
  );