JSFiddle - React, Tailwind, and code Playground

HTML

<div>
test
</div>

CSS

div { height: 2000px;}

JavaScript

/* var dealBar = function() {
        var scroll = document.documentElement.scrollTop;
        var sidebarDeals = document.querySelector('#sidebar__deals');
        var sidebarAdverts = document.querySelector('#sidebar__adverts');
        var adBottom = sidebarAdverts.offsetTop + sidebarAdverts.clientHeight;

        if (scroll > adBottom) {
            sidebarDeals.className = "sidebar__deals--fixed";
        } else {
            sidebarDeals.className = "sidebar__deals--relative";
        }       
    }*/

    window.addEventListener('scroll', function(e){
    console.log(e);
        //dealBar();
    });
    //dealBar();