JSFiddle - React, Tailwind, and code Playground
HTML
<div id="some-el" data-number="0">u</div>
JavaScript
$("#some-el").attr("data-number",1);
var d = $("#some-el").clone();
$("#some-el").append(d);
<div id="some-el" data-number="0">u</div>
$("#some-el").attr("data-number",1);
var d = $("#some-el").clone();
$("#some-el").append(d);