declare function auth(request: Request): { userId: number };

type Config<T> = {
  middleware(request: Request): Promise<T>
  onUpload(response: {
    metadata: T;
    file: any;
  }): void;
};

export declare function Helper<T extends Record<string, unknown>>(
  input: { [K in keyof T]: Config<T[K]> },
): void;

export const SomeFunc = Helper({
  someKey: {
    middleware: async (request: Request) => { // <------ YOU HAVE TO ANNOTATE REQUEST
      const user = await auth(request); 

      return { userIds: user.userId };
    },
    onUpload: async (response) => {
      console.log(response.metadata);
      //                  ^?

    },
  }
});

declare function auth(request: Request): { userId: number };

type Config<T> = {
  middleware(request: Request): Promise<T>
  onUpload(response: {
    metadata: T;
    file: any;
  }): void;
};

export declare function Helper<T extends Record<string, unknown>>(
  input: { [K in keyof T]: Config<T[K]> },
): void;

export const SomeFunc = Helper({
  someKey: {
    middleware: async (request: Request) => { // <------ YOU HAVE TO ANNOTATE REQUEST
      const user = await auth(request); 

      return { userIds: user.userId };
    },
    onUpload: async (response) => {
      console.log(response.metadata);
      //                  ^?

    },
  }
});

type OneThroughNine = 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
type Limit = `${OneThroughNine}${OneThroughNine}`

const x: Limit = ``

type OneThroughNine = 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
type Limit = `${OneThroughNine}${OneThroughNine}`

const x: Limit = ``