JSFiddle - React, Tailwind, and code Playground
by Curt
HTML
<div id="Listgroup">
<ul id="list1">
<li><a href="" data-value="1">my first item<span></span></a></li>
<li><a href="" data-value="2">another item<span></span></a></li>
<li><a href="" data-value="3">next item<span></span></a></li>
</ul>
<br>
<ul id="list2">
<li><a href="" data-value="a">my first item<span></span></a></li>
<li><a href="" data-value="b">another item<span></span></a></li>
<li><a href="" data-value="c">next item<span></span></a></li>
</ul>
</div>
JavaScript
$(function(){
$("li a").each(function(idx, item){
$(this).find("span").html(" (" + $(this).data("value") + ") ");
});
});