JSFiddle - React, Tailwind, and code Playground
HTML
<ul id="myList1"><li>Coffee</li><li>Tea</li></ul>
<ul id="myList2"><li>Water</li><li>Milk</li></ul>
<button onclick="myFunction()">Try it</button>
JavaScript
function myFunction() {
if($("#myList1").children().length < 5){
var itm = document.getElementById("myList2");
var cln = itm.cloneNode(true);
document.getElementById("myList1").appendChild(cln);
}
}