JSFiddle - React, Tailwind, and code Playground

HTML

<form>
  <input type="number">
</form>

JavaScript

$('input').keyup(function(){
    var $this = $(this);
    var num = $this.val().replace(/,/g, '');
    // the following line has been simplified. Revision history contains original.
    $this.val(num.replace(/(\d)(?=(\d{3})+(?!\d))/g, "$1,"));
  });