JSFiddle - React, Tailwind, and code Playground

by levchenko_d

HTML

<div class="demo">

  <div class="custom-scroll">
    <div class="stuff">
    At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Temporibus autem quibusdam et aut officiis debitis aut rerum necessitatibus saepe eveniet ut et voluptates repudiandae sint et molestiae non recusandae. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
    
    At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Temporibus autem quibusdam et aut officiis debitis aut rerum necessitatibus saepe eveniet ut et voluptates repudiandae sint et molestiae non recusandae. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
    
    At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident,...

CSS

/*------ Custom Scroll ------*/

.custom-scroll-wrapper {
  position: relative;
  overflow: hidden;
}

.custom-scroll-parent {
  width: 100%;
  padding-right: 30px;
}

.custom-scroll-master {
  position: absolute;
  top: 0;
  bottom: 0;
  right: 0;
  width: 16px;
  background: red;
  overflow: scroll;
  opacity: 0;
  z-index: 2;
}

.custom-scroll-scrollbar{
  position: absolute;
  top: 0;
  right: 4px;
  width: 8px;
  min-height: 20px;
  border-radius: 10px;
  opacity: 0;
  background: rgba(0,0,0,0.2);
}

.custom-scroll-master:hover ~ .custom-scroll-scrollbar {
  background: rgba(0,0,0,0.5);
}

.custom-scroll-scrolling .custom-scroll-scrollbar {
  opacity: 1;
}

.custom-scroll-end-scrolling .custom-scroll-scrollbar {
  -webkit-transition: opacity 0.25s ease-out;
  -moz-transition: opacity 0.25s ease-out;
  -ms-transition: opacity 0.25s ease-out;
  -o-transition: opacity 0.25s ease-out;
  transition: opacity 0.25s ease-out;
  opacity: 0;
}


/*---- Custom Scroll END ----*/









/* For demo */

.demo{
  width: 60%;
  height: 400px;
  margin: 50px auto;
  box-shadow: 0 2px 5px 1px rgba(0,0,0,0.15);
  border-radius: 7px;
}

.stuff{
  padding: 10px 20px;
}

JavaScript

/*------ customScroll ------*/

/*
	Options Description:
  
	options.element = Node; // Element to add scroll
  options.height = Int or 'auto'; //default 'auto' - 100% parent height

	Note:
  
  Use Scroll.calculateScrollbar(); when you change the content.
	______
  
  ToDo:
  
  [ ] Horizontal scroll(??)
  [✓] Responsiveness
  
*/

(function(){
	// Snippets
  function parseIntSafe(n){ return parseInt(n)||0; }
  function getHeight(el){ return Math.max(parseIntSafe(el.clientHeight), parseIntSafe(el.innerHeight)); };
  function hasClass(el, cls){ return (el.className.indexOf(cls) > -1);}
  function addClass(el, cls){ if(!hasClass(el, cls)){ el.className += ' '+cls;}}
  function removeClass(el, cls){ el.className = el.className.replace(new RegExp(cls, 'g'),'').trim();}
  

  var customScroll = function(options){
    var _t = this,
        o = options;

    _t.element = o.element;
    _t.parent = document.createElement('div');
    _t.content = document.createElement('div');
    _t.master = document.createElement('div');
    _t.contentShadow = document.createElement('div');
    _t.scrollbar = document.createElement('div');
    
    _t.height = parseInt(o.height) || _t.getParentHeight();

    _t.init();
  };

  customScroll.prototype.getParentHeight = function(){
  	var _t = this;
    return getHeight(_t.element.parentNode);
  };

  customScroll.prototype.calculateScrollbar = function(){
    var _t = this,
        contentHeight = getHeight(_t.content),
        percent = ((100/contentHeight) * _t.height)/100,
        sbHeight = _t.height * percent;

    _t.scrollbar.style.height = sbHeight +'px';
    _t.contentShadow.style.height = contentHeight +'px';
  };

  customScroll.prototype.attachEvents = function(){
    var _t = this,
        scrollEndTimeout = null,
        scrollStopTimeout = null;

    function handleScrollStart(){
			addClass(_t.element, 'custom-scroll-scrolling');
    };
    
    function handleScrollEnd(){
    	addClass(_t.element,...