express-validator not validating when seperated into several files

Question

I've got route file

import express, { Request, Response } from "express";
import * as authController from "../controllers/authController";
import {
  validateUserRegistration,  
} from "../validate/validationParams";

const router = express.Router();

router.post("/register", validateUserRegistration, authController.register);

export default router;

validationParams are in seperate file

import { check } from "express-validator";

export const validateUserRegistration = [
  check("firstName", "First Name is required").isString(),
  check("lastName", "Last Name is required").isString(),
  check("email", "Email is required").isEmail(),
  check("password", "Password with 6 or more characters required").isLength({
    min: 6,
  }),
];

and the main logic is in authController

import { validationResult } from "express-validator";
import catchAsync from "../utils/catchAsync";
import User from "../models/user";
export const register = catchAsync(async (req, res, next) => {
  console.log("register");

  const errors = validationResult(req);
  if (!errors.isEmpty()) {
    return res.status(400).json({
      message: errors.array(),
    });
  } else {
    console.log("errors are empty");
  }
  let user = await User.findOne({ email: req.body.email });
  if (user) return res.status(400).json({ message: "User already exists" });
  user = new User(req.body);
  await user.save();

  return res.status(201).send({ message: "User registered successfully" });
});

Unfortunately validator is not validating at all. when I run false req I get no errors. Is it possible to make it work properly or I must put everything in one file where it works fine ?