JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="listOne">
 <li><a>Text 1</a></li>
 <li><a>Text 2</a></li>
 <li><a>Text 3</a></li>
 <li><a>Text 4</a></li>
</ul>

JavaScript

$("a").click(function(){
      var itemsBefore = ($(this).parent().prev().length>0)
      var itemsAfter = ($(this).parent().next().length>0)
      if(itemsBefore && itemsAfter) alert("Previous and next");
      else if(itemsBefore) alert("Previous");
      else alert("Next");
  });