JSFiddle - React, Tailwind, and code Playground

by Thomas Gladdines

HTML

<h1>HTML Ipsum Presents</h1>
	       
<p><strong>Pellentesque habitant morbi tristique</strong> senectus et netus et malesuada fames ac turpis egestas. Vestibulum tortor quam, feugiat vitae, ultricies eget, tempor sit amet, ante. Donec eu libero sit amet quam egestas semper. <em>Aenean ultricies mi vitae est.</em> Mauris placerat eleifend leo. Quisque sit amet est et sapien ullamcorper pharetra. Vestibulum erat wisi, condimentum sed, <code>commodo vitae</code>, ornare sit amet, wisi. Aenean fermentum, elit eget tincidunt condimentum, eros ipsum rutrum orci, sagittis tempus lacus enim ac dui. <a href="#">Donec non enim</a> in turpis pulvinar facilisis. Ut felis.</p>

<h2>Header Level 2</h2>

<p>Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Vestibulum tortor quam, feugiat vitae, ultricies eget, tempor sit amet, ante. Donec eu libero sit amet quam egestas semper. Aenean ultricies mi vitae est. Mauris placerat eleifend leo.</p>
	       
<ol>
   <li>Lorem ipsum dolor sit amet, consectetuer adipiscing elit.</li>
   <li>Aliquam tincidunt mauris eu risus.</li>
</ol>

<blockquote><p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus magna. Cras in mi at felis aliquet congue. Ut a est eget ligula molestie gravida. Curabitur massa. Donec eleifend, libero at sagittis mollis, tellus est malesuada tellus, at luctus turpis elit sit amet quam. Vivamus pretium ornare est.</p></blockquote>

<p>Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Vestibulum tortor quam, feugiat vitae, ultricies eget, tempor sit amet, ante. Donec eu libero sit amet quam egestas semper. Aenean ultricies mi vitae est. Mauris placerat eleifend leo.</p>

<h3>Header Level 3</h3>

<ul>
   <li>Lorem ipsum dolor sit amet, consectetuer adipiscing elit.</li>
   <li>Aliquam tincidunt mauris eu risus.</li>
</ul>

<p>Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas....

JavaScript

(function iDirectionSpeed() {
	var distance = 50; //pixels to scroll to determine speed
	var preventLoop = true;
	var currentScroll = scrollTop();
	var currentDate = false;
	function scroll() {
		if(preventLoop) {
			//Set date on scroll
			if(!currentDate) {
				currentDate = new Date();
			}
		
			//Get new scroll position
			var newScroll = scrollTop();
			
			var scrolledDistance = Math.abs(currentScroll - newScroll);
			
			//User scrolled `distance` px or scrolled to the top/bottom
			if(scrolledDistance >= distance || !newScroll || newScroll == scrollHeight()) {
				//Stop scrolling
				preventLoop = false;
				freeze(newScroll);
			
				//Get new date
				var newDate = new Date();
				
				//Calculate time
				var time = newDate.getTime() - currentDate.getTime();
				
				//Output speed
				console.log("average speed: "+scrolledDistance+"px in "+time+"ms");
				
				/*
				To calculate the animation duration in ms:
				x: time
				y: distance
				z: distance you're going to animate
				
				animation duration = z / y * x
				*/
				
				//Check direction
				if(newScroll > currentScroll) {
					console.log("scrolling down");
					//scroll down animation  here
				} else {
				   console.log("scrolling up");
					//scroll up animation here
				}
				
				/*
				Time in milliseconds the scrolling is disabled,
				in most cases this is equal to the time the animation takes
				*/
				setTimeout(function() {
					//Update scroll position
					currentScroll = newScroll;
					
					//Unset date
					currentDate = false;
					
                	//Enable scrolling
					unfreeze();

					/*
					Wait 100ms before enabling the direction function again
					(to prevent a loop from occuring).
					*/
					setTimeout(function() {
						preventLoop = true;
					}, 100);
				}, 1000);
			}
		}
	}
	$(window).on("scroll", scroll);
})();

//Helper functions
function freeze(top) {
	if(window.innerWidth > document.documentElement.clientWidth) {
		$("html").css("overflow-y",...