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ミドルウェア

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t.procedure.use()メソッドを使用してプロシージャにミドルウェアを追加できます。ミドルウェアはプロシージャの呼び出しをラップし、その戻り値を通過させなければなりません。

認可

以下の例では、adminProcedureへの呼び出し時にユーザーが「admin」であることを確認してから実行します。

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,
});

ヒント

上記の例でスローされるTRPCErrorの詳細については、エラーハンドリングを参照してください。

ロギング

以下の例では、クエリの実行時間が自動的にログ記録されます。

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'),
});

コンテキスト拡張

「コンテキスト拡張」により、ミドルウェアはベースプロシージャのコンテキストに対して型安全な方法でキーの動的な追加や上書きが可能になります。

以下はコンテキストのプロパティを変更するミドルウェアの例です。変更後は、他のミドルウェアやプロシージャなど、チェーンされたすべてのコンシューマーが変更内容を利用できます。

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;
}

ミドルウェアの拡張

情報

新規APIのためunstable_プレフィックスを付けていますが、安全に利用できます！詳細はこちら

.pipe()という強力な機能を使用すると、ミドルウェアを型安全な方法で拡張できます。

以下はベースミドルウェア（foo）を拡張するミドルウェアの例です。前述のコンテキスト拡張の例と同様に、ミドルウェアをパイプするとコンテキストのプロパティが変更され、プロシージャは新しいコンテキスト値を受け取ります。

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";
}

ミドルウェアをパイプする順序は重要であり、コンテキストが重複している必要がある点に注意してください。以下に禁止されるパイプの例を示します。ここではfooMiddlewareがctx.aを上書きしますが、barMiddlewareはinitTRPC初期化時のルートコンテキストを期待しています。そのためfooMiddlewareとbarMiddlewareのパイプは機能せず、barMiddlewareとfooMiddlewareのパイプは機能します。

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);

実験的: スタンドアロンミドルウェア

情報

注意: この機能には experimental_ プレフィックスが付いており、どの tRPC リリースでも変更される可能性があります。詳細はこちら

tRPCにはexperimental_standaloneMiddlewareという新しい実験的APIが導入されました。これにより、任意のtRPCインスタンスで使用できるミドルウェアを独立して定義できます。従来のt.middlewareを使用したミドルウェア作成では、Context型がtRPCインスタンスのContext型に紐づくという制限がありました。つまり、異なるContext型を持つ複数のtRPCインスタンスで同じミドルウェアを使用することはできません。

experimental_standaloneMiddlewareを使用すると、要件（Context、Input、Metaの型）を明示的に定義するミドルウェアを作成できます。

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'.

以下は複数のスタンドアロンミドルウェアの例です。

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}`,
  );

認可​

ロギング​

コンテキスト拡張​

ミドルウェアの拡張​

実験的: スタンドアロンミドルウェア​

認可

ロギング

コンテキスト拡張

ミドルウェアの拡張

実験的: スタンドアロンミドルウェア