I'm trying to do validation test by using express-validator.

so far everything is working good except isStrongPassword()

import {check} from "express-validator"


const val =   
    check('pwd')
        .exists()
        .withMessage('please enter the password')
        .isStrongPassword({minLength: 6})
        .withMessage('password is must be above six letters')

Router.post('/signup',val,SignUp)


const SignUp = async(req,res) => {
    // if email and password are invalid  throw the errors
    const errors = validationResult(req).array();
    if (errors && errors.length) {
    console.log(errors);
    res.status(400).json({ errors });

my code is like that .but when I request password 1 letter or 7 letters regardless It just call error. It seems to be doesn`t work anybody who knows why it happened? Thank you for your attention