JSFiddle - React, Tailwind, and code Playground

HTML

<div id="con">
    <div> 1 </div>
    <div> 2 </div>
    <div> 3 </div>
    <div> 4 </div>
    <div> 5 </div>
</div>

<div id="bar">
    <div> a </div>
    <div> b </div>
    <div> c </div>
    <div> d </div>
    <div> e </div>
</div>

JavaScript

$.fn.reverseChildren = function() {
  return this.each(function(){
    var $this = $(this);
    $this.children().each(function(){
      $this.prepend(this);
    });
  });
};
$('#con,#bar').reverseChildren();