JSFiddle - React, Tailwind, and code Playground

by Serhii Matrunchyk

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.27.0/moment.min.js" integrity="sha512-rmZcZsyhe0/MAjquhTgiUcb4d9knaFc7b5xAfju483gbEXTkeJRUMIPk6s3ySZMYUHEcjKbjLjyddGWMrNEvZg==" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment-timezone/0.5.31/moment-timezone-with-data.min.js" integrity="sha512-HZcf3uHWA+Y2P5KNv+F/xa87/flKVP92kUTe/KXjU8URPshczF1Dx+cL5bw0VBGhmqWAK0UbhcqxBbyiNtAnWQ==" crossorigin="anonymous"></script>

JavaScript

function utcToUserDate(date) {
  const utcDate = moment.tz(date, "Etc/UTC");
  const userTz = moment.tz.guess(true);

  return utcDate.tz(userTz).format();
}

const result = prompt('Enter UTC date');
alert(utcToUserDate(result));