JSFiddle - React, Tailwind, and code Playground

HTML

<date-today></date-today>
<date-today></date-today>

JavaScript

"use strict";

var _inherits = function (child, parent) {
  child.prototype = Object.create(parent && parent.prototype, {
    constructor: {
      value: child,
      enumerable: false,
      writable: true,
      configurable: true
    }
  });
  if (parent) child.__proto__ = parent;
};

var DateSpan = (function () {
  var _HTMLSpanElement = HTMLSpanElement;
  var DateSpan = function DateSpan() {
    if (_HTMLSpanElement) {
      _HTMLSpanElement.apply(this, arguments);
    }
  };

  _inherits(DateSpan, _HTMLSpanElement);

  DateSpan.prototype.createdCallback = function () {
    this.textContent = "Today's date: " + new Date().toJSON().slice(0, 10);
  };

  return DateSpan;
})();

document.registerElement("date-today", DateSpan);