JSFiddle - React, Tailwind, and code Playground

HTML

<p id="demo"></p>

JavaScript

var myVar = setInterval(function(){calcTime('Kolkata', '+5.5')}, 1000);
function calcTime(city, offset) {

   d = new Date();
   utc = d.getTime() + (d.getTimezoneOffset() * 60000);    
   nd = new Date(utc + (3600000*offset));    
   document.getElementById("demo").innerHTML = nd.toLocaleString();

}