Generics for Input

[masterbater]

Ive been struggling to properly type an extracted function, Im a noob in typescript and just keep learning of it, im still in a phase where I keep pulling my hair when it doesnt work.

controller.ts

import { zValidator } from "@hono/zod-validator";
import { Env, Handler, Hono } from "hono";
import { z } from "zod";
import { prismaMiddleware } from "../config/db";
import { getTeachers } from "./service";
export const teacherController = new Hono();

const zodSchema = z.object({
  page: z.string(),
});
const validateSchema = zValidator(
  "query",
  z.object({
    page: z.string(),
  })
);
type zodSchemaType = z.infer<typeof zodSchema>;
type ThirdParamType = Handler<Env, any, {}>;
export type TValidate = typeof validateSchema;

teacherController.get("/", prismaMiddleware, validateSchema, getTeachers);

service.ts

import { Context, Env, Handler } from "hono";
import { env } from "hono/adapter";
import extension from "prisma-paginate";

export const getTeachers = async (c: Context<Env, any, whatToPutHere>) => {
  const { NODE_ENV } = env(c);
  const prisma = c.get("prisma");
  const { page } = c.req.valid("query");

  const paginatePrisma = prisma.$extends(extension);
  const user = await paginatePrisma.user.paginate({
    page: parseInt(page),
    limit: 2,
  });

  return c.jsonT({
    ...user,
    hasNextPage: user.hasNextPage,
    hasPrevPage: user.hasPrevPage,
  });
};

This types everything except the inputs, I extracted the type of zValidator its not compatible to whatToPutHere
export const getTeachers = async (c: Context<Env, any, whatToPutHere>)

I also infer zod schema it returns this

type zodSchemaType = {
    page: string;
}

But input expected like this

{
    in: {
        query: {
            page: string;
        };
    };
    out: {
        query: {
            page: string;
        };
    };

Is there a builtin helper in typescript or in hono that makes types above using like

RequestInputType<zodSchemaType>

then it generates a type like above?

[Zegnat]

I ran into a similar thing, and thought I would share what I ended up with at one point.

controller.ts

import { Hono } from "hono";
import { prismaMiddleware } from "../config/db";
import { getTeachers, getTeachersValidator } from "./services";
export const teacherController = new Hono();

teacherController.get("/", prismaMiddleware, getTeachersValidator, getTeachers);

service.ts

import { zValidator } from "@hono/zod-validator";
import { env } from "hono/adapter";
import extension from "prisma-paginate";
import { z } from "zod";

const teachersSchema = z.object({
    page: z.string(),
  });

export const getTeachersValidator = zValidator("query", teachersSchema)

type ValidatorContext = Parameters<typeof getTeachersValidator>[0]

export const getTeachers = async (c: ValidatorContext) => {
  const { NODE_ENV } = env(c);
  const prisma = c.get("prisma");
  const { page } = c.req.valid("query");

  const paginatePrisma = prisma.$extends(extension);
  const user = await paginatePrisma.user.paginate({
    page: parseInt(page),
    limit: 2,
  });

  return c.jsonT({
    ...user,
    hasNextPage: user.hasNextPage,
    hasPrevPage: user.hasPrevPage,
  });
};

Basically I made sure the validator was defined in the same place as my actual request handler. I then forward the Context generated by zValidator straight into the handler function. This seemed to give me all the typing I expected.