How to pass-thru if zod schema provided to be able to chain further

[stychu]

I have a endpoint utility where I create endpoint contracts for APIs but currently when defining zod schemas I cannot re-use them for other places where I could to avoid duplication. The resulting type of zod schema seems to be lost somewhere alongside cant figure it out where and how to make it work whilst preserving the logic for defining endpoint props.

https://tsplay.dev/mbbPBm

import { z } from 'zod'

type HttpMethod = 'GET' | 'POST' | 'PUT' | 'PATCH' | 'DELETE';

type ExtractParams<Path extends string> =
    Path extends `${infer _Start}:${infer Param}/${infer Rest}`
    ? { [K in Param]: string } & ExtractParams<`/${Rest}`>
    : Path extends `${infer _Start}:${infer Param}`
    ? { [K in Param]: string }
    : {};

type Endpoint<
    TPath extends string = string,
    TMethod extends HttpMethod = 'GET',
    TQuery = unknown,
    TBody = unknown,
    TResponse = unknown,
> = {
    readonly method: TMethod;
    readonly path: TPath;
    readonly response: z.ZodSchema<TResponse>;
} & (TQuery extends object
    ? { query: z.ZodSchema<TQuery> }
    : { query?: never }) &
    (TBody extends object ? { body: z.ZodSchema<TBody> } : { body?: never }) &
    (keyof ExtractParams<TPath> extends never
        ? { readonly pathParams?: never }
        : { readonly pathParams: z.ZodSchema<ExtractParams<TPath>> });

function endpoint<
    TPath extends string,
    TMethod extends HttpMethod,
    TQuery,
    TBody,
    TResponse,
>(
    def: Endpoint<TPath, TMethod, TQuery, TBody, TResponse>,
): Endpoint<TPath, TMethod, TQuery, TBody, TResponse> {
    return def;
}

const contract = {
    get: endpoint({
        method: 'GET',
        path: '/v1/get',
        query: z.object({
            from: z.string(),
            to: z.string(),
            gtin: z.string().optional(),
            store: z.string().optional(),
            reasons: z.string().optional(),
        }),
        response: z.object({
            products: z
                .object({
                    description: z.string(),
                    soldQuantity: z.number(),
                })
                .array(),
        }),
    }),
};



contract.get.query.pick      // doesnt work
contract.get.query.merge      // doesnt work
contract.get.query.extend       // doesnt work

Can someone guide me how can I achieve this?