trpc-compat.ts

import type { AnyRouter as TRPCAnyRouter, AnyProcedure as TRPCAnyProcedure } from '@trpc/server';

/**
 * Types that approximate a tRPC v11 router and procedure to infer types correctly.
 * Written to avoid direct dependency on @trpc/server v11+.
 */
export type Trpc11RouterLike = {
  _def: {
    _config: {
      $types: { meta: unknown; ctx: unknown };
    };
    procedures: Record<
      string,
      Trpc11ProcedureLike | Trpc11RouterLike | Record<string, Trpc11ProcedureLike>
    >;
  };
};

export type Trpc11ProcedureLike = {
  _def: {
    type: 'mutation' | 'query' | 'subscription';
    meta?: unknown;
    inputs?: unknown[]; // Not exposed by tRPC v11 as of 11.0.0-rc.502
    $types: { input: unknown; output: unknown };
  };
};

export type Trpc10RouterLike = {
  _def: {
    _config: {
      $types: { meta: unknown; ctx: unknown };
    };
    procedures: Record<string, Trpc10ProcedureLike | Trpc10RouterLike>;
  };
};

export type Trpc10ProcedureLike = {
  _def: {
    mutation?: boolean;
    query?: boolean;
    subscription?: boolean;
    meta?: unknown;
    inputs: unknown[];
    _input_in: unknown;
    _output_out: unknown;
  };
};

export type CreateCallerFactoryLike = (
  router: unknown
) => (context: unknown) => Record<string, (input: unknown) => unknown>;

export type AnyRouter = Trpc10RouterLike | Trpc11RouterLike | TRPCAnyRouter | { link: any };

export type AnyProcedure = Trpc10ProcedureLike | Trpc11ProcedureLike | TRPCAnyProcedure;

export type InferRouterContext<R extends AnyRouter> = R['_def']['_config']['$types']['ctx'];

export const isTrpc11Procedure = (procedure: AnyProcedure): procedure is Trpc11ProcedureLike => {
  return '_def' in procedure && 'type' in procedure._def && typeof procedure._def.type === 'string';
};

export const isTrpc11Router = (router: AnyRouter): router is Trpc11RouterLike => {
  const procedure = Object.values(router._def.procedures)[0] as AnyProcedure | undefined;
  return procedure ? isTrpc11Procedure(procedure) : false;
};