feat(toc): ✨ add folding TOC elements for more compact TOC table

www/static/dergstyle.css

@@ -165,8 +165,11 @@ a:hover {
 	margin-right: 2rem;
 }
 
-:target { 
+:target, html, body { 
-	scroll-margin-top: 6rem;
+	scroll-margin-top: 140px;
+}
+:target {
+	outline: 1px solid var(--highlight_1);
 }
 
 #main_content_flexbox {

www/static/styles/toc.css

@@ -37,7 +37,7 @@
     color: var(--toc-fg) !important;
   }
   
-  & .active {
+  & .active > a {
     background-color: var(--toc-bg);
     border-bottom: 1px solid var(--highlight_1);
     
@@ -57,4 +57,11 @@
     margin-bottom: 0.2em;
     transition: all 1s;
   }
+  
+  & .toc_collapsing {
+    display: none;
+  }
+  & li:is(:has(.active),.active) > ol > .toc_collapsing {
+    display: block;
+  }
 }

www/static/toc.js

@@ -7,7 +7,7 @@ let tocId = "toc";
 
 const TOC_IDENTIFIER = "toc";
 const TOC_MAIN_CONTENT_ID = "#content_article"
-const TOC_TOP_PIXEL_MARGIN = 300;
+const TOC_TOP_PIXEL_MARGIN = 150;
 
 class TocTracker {
   known_heading_elements = [];
@@ -49,14 +49,25 @@ class TocTracker {
       throw Error("A `main` tag section is required to query headings from.");
     }
     
-    let headings = main.querySelectorAll("h1, h2, h3, h4, h5, h6");
+    let headings = main.querySelectorAll("h1, h2, h3, h4, h5, h6, li strong");
     headings.forEach((heading, index) => {
-      const heading_level = parseInt(heading.tagName.slice(-1));
+      let heading_level = parseInt(heading.tagName.slice(-1));
+      let heading_collapsed = false;
+
+	  let heading_name = heading.innerHTML;
+      
+	  if(heading.tagName == 'STRONG') {
+	  	heading_level = -1;
+	  	heading_collapsed = true;
+
+	  	heading = heading.closest('li');
+	  }
 
       this.known_heading_elements.push({
         level: heading_level,
-        name: heading.innerHTML,
+        name: heading_name,
         dom: heading,
+        collapse: heading_collapsed
       });
     });
   }
@@ -65,6 +76,23 @@ class TocTracker {
     this.known_heading_elements.sort((a, b) => {
       return a.dom.getBoundingClientRect().y 
         - b.dom.getBoundingClientRect().y;
+    });
+
+	let lastHeadingLevel = 0;
+    this.known_heading_elements.forEach((element) => {
+    	if(element.level == -1) {
+    		let extra_depth = 0;
+    		let current_dom = element.dom;
+    		while(current_dom.tagName != 'ARTICLE') {
+    			if((current_dom.tagName == 'OL') || (current_dom.tagName == 'UL'))
+    				extra_depth += 1;
+
+    			current_dom = current_dom.parentElement.closest('ol,ul,article');
+    		}
+    		element.level = lastHeadingLevel+extra_depth;
+    	}
+    	else
+    		lastHeadingLevel = element.level;
     });
   }
 
@@ -192,7 +220,7 @@ class TocNavBarUpdater {
       let newNode = document.createElement('li');
 
       const pathURL = location.pathname + '#' + pathItem.id + location.search;
-      newNode.innerHTML = "<a href=" + pathURL + "> #<sub>" + pathItem.level + '</sub>' + pathItem.name + '</a>'
+      newNode.innerHTML = "<a hx-boost=false href=" + pathURL + "> #<sub>" + pathItem.level + '</sub>' + pathItem.name + '</a>'
       
       this.navbar_dom.appendChild(newNode);
       this.added_navbar_elements.push(newNode);
@@ -224,17 +252,37 @@ class TocSidemenu {
   }
 
   _generateSidebar() {
-    this.toc_tracker.known_heading_elements.forEach(element => {
+	let toc_stack = [this.sidebar_dom];
-      let new_element = document.createElement('li');
+	let last_added_li = null;
 
+    this.toc_tracker.known_heading_elements.forEach(element => {
+	  while(element.level > toc_stack.length) {
+		if(!last_added_li) {
+			last_added_li = document.createElement('li');
+			toc_stack[toc_stack.length-1].appendChild(last_added_li);
+		}
+	  	
+	  	let new_ol = document.createElement('ol');
+	  	last_added_li.appendChild(new_ol);
+		last_added_li = false;
+	  	toc_stack.push(new_ol);
+	  }
+	  while(element.level < toc_stack.length)
+	  	toc_stack.pop();
+
+    
+      let new_element = document.createElement('li');
+	  last_added_li = new_element;
+	  
       const pathURL = location.pathname + '#' + element.id + location.search;
 
-      new_element.style = "padding-left: " + element.level * 0.8 + "em";
+      new_element.innerHTML = "<a hx-boost=false style=\"padding-left: " + element.level * 0.8 + "em\" href=" + pathURL + ">" + element.name + "</a>";
-      new_element.innerHTML = "<a href=" + pathURL + ">" + element.name + "</a>";
+      if(element.collapse)
+      	new_element.classList.add('toc_collapsing');
 
       this.sidebar_elements[element.id] = new_element;
 
-      this.sidebar_dom.appendChild(new_element);
+      toc_stack[toc_stack.length-1].appendChild(new_element);
     });
   }
 
@@ -251,13 +299,18 @@ class TocSidemenu {
     if(this.currently_active_entry) {
       this.currently_active_entry.classList.remove('active');
     }
+    Object.values(this.sidebar_elements).forEach((entry) => entry.classList.remove('contains_active'));
 
     let active_entry = this.sidebar_elements[entry.dom.id];
     active_entry.classList.add('active');
     this.currently_active_entry = active_entry;
+
+   	entry.path.forEach((path_piece) => this.sidebar_elements[path_piece.id].classList.add('contains_active'));
   }
 }
 
 let tracker = new TocTracker();
 let navbar_updater = new TocNavBarUpdater(tracker);
-let sidebar_updater = new TocSidemenu(tracker);
+let sidebar_updater = new TocSidemenu(tracker);
+
+document.addEventListener('DOMContentLoaded', (event) => tracker.reloadHeadings());