Universal zod validator for express.js

validator.middleware.ts

import { AnyZodObject, ZodTypeAny } from 'zod'
import {
  NextFunction,
  Request,
  RequestHandler,
  Response
} from 'express'
import { HttpError } from '@/lib/errors.lib'

type RequestPayloadIn = 'body' | 'query' | 'params'

const validator =
  (
    args: Partial<
      Record<RequestPayloadIn, AnyZodObject | ZodTypeAny>
    >
  ): RequestHandler =>
  async (
    req: Request,
    res: Response,
    next: NextFunction
  ): Promise<void> => {
    try {
      const keys = Object.keys(args) as RequestPayloadIn[]

      for (const key of keys) {
        const payload = req[key]
        console.log(payload)
        const validator = args[key]

        if (validator) {
          const result = validator.safeParse(payload)
          if (!result.success) {
            console.log(result.error.flatten())

            next(
              new HttpError({
                statusCode: 422,
                message: 'Unprocessable Entity Error',
                errors: result.error.errors
              })
            )
            return
          }

          if (result.data) {
            req[key] = result.data
          }
        }
      }
      next()
    } catch (err) {
      next(
        new HttpError({
          statusCode: 500,
          message:
            (err as Error).stack ?? (err as Error).message
        })
      )
    }
  }

export default validator