How to use regular expressions in Lightning Webcomponents

panCardValidation.html
======================
<template>
    <lightning-input label="Enter the pancard number" class="panCard">
    </lightning-input>
    <lightning-button label="Submit" onclick={handleValidate}>
    </lightning-button>
</template>

panCardValidation.js
====================
import { LightningElement } from 'lwc';
export default class PanCardValidtion extends LightningElement {
    handleValidate(){
        const panCardRegex="[A-Z]{5}[0-9]{4}[A-Z]{1}";
        let panCard=this.template.querySelector(".panCard");
        let panCardVal=panCard.value;
        if(panCardVal.match(panCardRegex)){
            panCard.setCustomValidity("");

        }else{
            panCard.setCustomValidity("Please Enter the valid PanCard Number");
        }
        panCard.reportValidity();
    }
}