Add a scrollable ToC (incl. "back to top"-link) to the Laravel Docs

README.TXT

# Description
For some reason the Laravel Docs don't have a scrollable Table of Contents. Nor a "back to top"-link. Which I found very annoying.. Luckily that was rather easily fixed with a bit of custom CSS/JS "magic" ;-) 


# What you need:
1. A browser extension for adding custom CSS and JS to websites of your choice.
  a. User Javascript and CSS (Chrome): https://chromewebstore.google.com/detail/user-javascript-and-css/nbhcbdghjpllgmfilhnhkllmkecfmpld
  b. Firemonkey (Firefox): https://addons.mozilla.org/nl/firefox/addon/firemonkey/
2. Settings (based on the Chrome extension, which I use):
  a. URL pattern: `https://laravel.com/docs/*`
  b. Active modules: jQuery 3 (I don't know about Firemonkey, but in the Chrome-extension this was easily activated with a checkbox)
  c. JavaScript settings: Run at the start (which may or may not be active by default)
  d. The rule itself has to be activated, obviously ;-)

custom.css

// Defaults
:root {
	--ci-primary-color: var(--color-laravel-red, #f61500);
	--ci-bg-color: var(--docsearch-footer-background);
	--ci-content-before-item: "# ";
	--ci-content-before-item-active: '❯ ';
}

// Light theme
html[data-theme="light"] {
	--ci-box-shadow: rgba(187,187,187,1);
	
	--ci-header-color: var(--color-sand-light-1);
	--ci-link-color: var(--color-sand-light-12);
	--ci-icon-color: var(--ci-header-color);
	--ci-icon-bg-hover-color: var(--docsearch-hit-color, #333);
	
	--ci-active-border-color: rgba(150,159,175,0.25);
}
// Dark theme
html[data-theme="dark"] {
	--ci-box-shadow: var(--color-sand-dark-3);
	
	--ci-header-color: var(--color-sand-light-1);
	--ci-link-color: var(--color-sand-dark-11);
	--ci-icon-color: var(--ci-header-color);
	--ci-icon-bg-hover-color: var(--docsearch-hit-color);
	
	--ci-active-border-color: rgba(150,159,175,0.25);
}


// The actual CSS
html {
	scroll-behavior: smooth;
}

#main-content h1 + ul li,
#main-content h1 + ul ul {
	padding: 0;
	margin: 0;
}
#main-content h1 + ul a {
	padding: .5rem;
	display: block;
}
#main-content h1 + ul a:hover {
	text-decoration: underline;
}
#main-content h1 + ul ul li {
	margin-left: 1rem;
}

body.hasCustomIndex {
	position: relative;
}
body.hasCustomIndex #customDocIndex {
	position: fixed;
	right: 1rem;
	bottom: 1rem;
	display: block;
	background: var(--ci-bg-color);
	z-index: 2;
	font-size: .9rem;
	min-width: 20rem;
	-webkit-box-shadow: 0px 0px 5px 0px var(--ci-box-shadow);
	-moz-box-shadow: 0px 0px 5px 0px var(--ci-box-shadow);
	box-shadow: 0px 0px 5px 0px var(--ci-box-shadow);
}

body.hasCustomIndex #customDocIndex * {
	transition: all .2s ease;
	-moz-transition: all .2s ease;
	-webkit-transition: all .2s ease-in-out;
}

body.hasCustomIndex #customDocIndex h1 {
	font-weight: bold;
	color: var(--ci-header-color);
	background-color: var(--ci-primary-color);
	padding: .5rem 1rem;
	font-size: 1rem;
	position: relative;
}
body.hasCustomIndex #customDocIndex h1 span {
	position: absolute;
	right: 0;
	top: 0;
	display: block;
	width: auto;
	height: 100%;
	font-weight: 900;
}

body.hasCustomIndex #customDocIndex h1 .back-to-top,
body.hasCustomIndex #collapseCustomDocIndex {
	display: inline-block;
	padding: .5rem 1rem;
	background-color: var(--ci-primary-color);
	color: var(--ci-icon-color);
}
body.hasCustomIndex #collapseCustomDocIndex {
	transform: rotate(90deg);
	height: 100%;
	width: auto;
}
body.hasCustomIndex #collapseCustomDocIndex::before {
	display: block;
	height: 2rem;
}
body.hasCustomIndex #customDocIndex h1 .back-to-top {
	font-weight: 900;
}
body.hasCustomIndex #customDocIndex h1 .back-to-top:hover,
body.hasCustomIndex #collapseCustomDocIndex:hover {
	background-color: var(--ci-icon-bg-hover-color);
	text-decoration: none;
	cursor: pointer;
}
body.hasCustomIndex #collapseCustomDocIndex.collapsed::before {
	content: '❯';
}
body.hasCustomIndex #collapseCustomDocIndex.folded::before {
	content: '❮';
}

body.hasCustomIndex #customDocIndexList {
	display: block;
	overflow-y: auto;
	max-height: calc(100vh - 4.75rem);
}

body.hasCustomIndex #customDocIndexList > ul {
	padding: 1rem 1rem 3rem 1rem;
}

body.hasCustomIndex #customDocIndex li:before {
	content: var(--ci-content-before-item);
	color: var(--ci-primary-color);
	position: absolute;
	width: .5rem;
	height: 1.8em;
	vertical-align: middle;
	
}
body.hasCustomIndex #customDocIndex li.active:before {
	content: var(--ci-content-before-item-active);
}

body.hasCustomIndex #customDocIndex li {
	font-weight: 500;
	line-height: 2em;
	position: relative;
}

body.hasCustomIndex #customDocIndex li ul {
	margin-left: 1rem;
}
body.hasCustomIndex #customDocIndex .subheaders li {
	font-weight: normal;
	font-size: 90%;
}

body.hasCustomIndex #customDocIndex > ul > li {
	border-right: .2rem solid var(--custom-index-background);
}
body.hasCustomIndex #customDocIndex > ul > li.active {
	border-color: var(--ci-active-border-color);
}
body.hasCustomIndex #customDocIndex li.active > a {
	text-decoration: underline;
}
body.hasCustomIndex #customDocIndex ul:not(.subheaders) li.active > a {
	font-weight: 900;
}
body.hasCustomIndex #customDocIndex li.active li.active > a {
	font-weight: inherit;
}
body.hasCustomIndex #customDocIndex li.active > a:hover {
	text-decoration: none;
}
body.hasCustomIndex #customDocIndex li a {
	display: block;
	padding-left: 1rem;
	transition: all 100ms ease-in-out;
	color: var(--ci-link-color);
}
body.hasCustomIndex #customDocIndex a:hover {
	text-decoration: underline;
}



body.hasCustomIndex #customBackToTop {
	position: relative;
	display: block;
}
body.hasCustomIndex #customBackToTop a {
	position: absolute;
	display: block;
	right: 0;
	bottom: 0;
	padding: .5rem 1rem;
	background-color: var(--ci-primary-color);
	color: var(--ci-icon-color);
	font-weight: 900;
	font-size: 1rem;
}
body.hasCustomIndex #customBackToTop a:hover {
	background-color: var(--ci-icon-bg-hover-color);
	text-decoration: none;
}


/* Carbon Ads at the bottom (hiding it to prevent overlap issues with the "back to top" / ToC elements) */
#carbonads {
	z-index: 0;
	right: -100rem;
	bottom: -100rem;
}

custom.js

jQuery( document ).ready(function($) {
	
	$('#on-this-page-content').parent().parent().parent().remove();
	
	if ($('#main-content h1 + ul').length > 0) {
		const docIndex = $('#main-content h1 + ul');
		
		$('body').addClass('hasCustomIndex');
		$('body').append('<aside id="customDocIndex" class="shadow-lg"><h1>Table of Contents <span><button id="collapseCustomDocIndex" class="collapsed" title="Toggle Index" aria-collapsed="true"></button><a href="#main-content" class="back-to-top" style="display:none" title="Back to Top">&uarr;</a></span></h1><div id="customDocIndexList"><ul></ul></div></aside>');
		
		$('#main-content h2').each(function (){
			const articleSection = $(this).nextUntil('h2').addBack();
			const sectionId = $(this).attr('id');
			articleSection.wrapAll( '<section class="article-section" id="section-'+sectionId+'"></section>' );
		});
		
		// Walk through the sections
		$('section.article-section').each(function(){
			const sectionHeader = $(this).find('h2');
			const sectionHeaderId = $(sectionHeader).attr('id');
			
			$('<li id="sectionLink-'+sectionHeaderId+'"><a href="#section-'+sectionHeaderId+'">'+$(sectionHeader).text()+'</a></li>').appendTo('#customDocIndexList > ul');
			
			// Walk through the subsections (if they exist)
			const sectionSubheaders = $(this).find('h3');
			if (sectionSubheaders.length) {
				$('<ul class="subheaders"></ul>').appendTo('li#sectionLink-'+sectionHeaderId);
				
				$(sectionSubheaders).each(function(){
					const sectionSubheaderId = $(this).attr('id');
					$('<li id="sectionLink-'+sectionSubheaderId+'" class="parentElement-'+sectionHeaderId+'"><a href="#'+sectionSubheaderId+'">'+$(this).text()+'</a></li>').appendTo('#sectionLink-'+sectionHeaderId+' ul.subheaders');
				});
			}
		});
		
		/* Add a "Back to Top"-link while we're at it */
		$('<div id="customBackToTop"><a href="#main-content" title="Back to Top">&uarr;</a></div>').appendTo('#customDocIndex');
		
		
		$('#collapseCustomDocIndex').on('click', function() {
			if ($(this).hasClass('collapsed')) {
				$(this).addClass('folded').removeClass('collapsed');
				$('#customDocIndexList > ul, #customBackToTop').hide();
				$('#customDocIndex h1 .back-to-top').show();
				$('#collapseCustomDocIndex').attr('aria-collapsed', false);
			}
			else {
				$(this).addClass('collapsed').removeClass('folded');
				$('#customDocIndexList > ul, #customBackToTop').show();
				$('#customDocIndex h1 .back-to-top').hide();
				$('#collapseCustomDocIndex').attr('aria-collapsed', true);
			}
		});
	}
	
});


/* Smooth Scrolling Sticky Scrollspy Navigation: 
 * https://www.bram.us/2020/01/10/smooth-scrolling-sticky-scrollspy-navigation/ 
 */
window.addEventListener('DOMContentLoaded', () => {

	const observer = new IntersectionObserver(entries => {
		entries.forEach(entry => {
			const id = entry.target.getAttribute('id');
			if (entry.intersectionRatio > 0) {
				document.querySelector(`#customDocIndex a[href="#${id}"]`).parentElement.classList.add('active');
			} else {
				document.querySelector(`#customDocIndex a[href="#${id}"]`).parentElement.classList.remove('active');
			}
		});
	});

	setTimeout(function (){
		// Track all sections that have an `id` applied
		document.querySelectorAll('section[id], section[id] h3').forEach((section) => {
			observer.observe(section);
		});
	}, 10);
});

Made some changes to the CSS to respect the active data theme for the Docs

Recently Laravel introduced their own Table of Contents solution in their docs, but I like my solution better (being able to collapse it + having a back-to-top button). So I've added removing their solution to the JavaScript