JSFiddle - React, Tailwind, and code Playground

HTML

<div class="main" id="clicker">
  Expand
</div>
<div class="secondary" id="expandable">
  number1, <br> number2, <br> number3, <br> number4.
</div>

JavaScript

$( document ).ready(function() {
  
$(".secondary").hide();

$(document).ready(
    function(){
        $("#clicker").click(function () {
            $(".secondary").toggle("slow");
        });

    });   
   
});