JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <div>
        <span>Fe</span>
        <span>Fi</span>
        <span>Fo</span>
        <span>Fum</span>
    </div>


    <div>
        <span>He</span>
        <span>Hi</span>
        <span>Ho</span>
        <span>Hum</span>
    </div>
</div>

JavaScript

jQuery.fn.swap = function(b){ 
    b = jQuery(b)[0]; 
    var a = this[0]; 
    var t = a.parentNode.insertBefore(document.createTextNode(''), a); 
    b.parentNode.insertBefore(a, b); 
    t.parentNode.insertBefore(b, t); 
    t.parentNode.removeChild(t); 
    return this; 
};

$(function() {
    $('div > div:first').swap('div > div:last');    
});