Header links

app/Markdown/ConfigureHeadingLinks.php

@@ -0,0 +1,50 @@
+<?php
+
+namespace App\Markdown;
+
+use League\CommonMark\Event\DocumentParsedEvent;
+use League\CommonMark\Extension\CommonMark\Node\Block\Heading;
+use League\CommonMark\Extension\CommonMark\Node\Inline\HtmlInline;
+use League\CommonMark\Node\Block\Paragraph;
+
+class ConfigureHeadingLinks
+{
+    public function __invoke(DocumentParsedEvent $documentParsedEvent): void
+    {
+        $walker = $documentParsedEvent->getDocument()->walker();
+
+        while ($event = $walker->next()) {
+            [$paragraph, $heading, $linkOpener, $linkCloser] = [
+                $event->getNode(),
+                $event->getNode()->next(),
+                $event->getNode()->firstChild(),
+                $event->getNode()->lastChild(),
+            ];
+
+            if (
+                ! $heading instanceof Heading ||
+                ! $paragraph instanceof Paragraph ||
+                count($paragraph->children()) !== 2 ||
+                ! $linkOpener instanceof HtmlInline ||
+                ! $linkCloser instanceof HtmlInline ||
+                ! str_starts_with($linkOpener->getLiteral(), '<a name="') ||
+                ! str_ends_with($linkOpener->getLiteral(), '">') ||
+                substr_count($linkOpener->getLiteral(), '"') !== 2 ||
+                $paragraph->firstChild()->next() !== $paragraph->lastChild() ||
+                ! str_starts_with($linkCloser->getLiteral(), '</a>')
+            ) {
+                continue;
+            }
+
+            $link = str($linkOpener->getLiteral())->after('<a name="')->beforeLast('">')->toString();
+
+            $heading->data->set('attributes.id', $link);
+            $heading->prependChild(new HtmlInline('<a href="#'.$link.'">'));
+            $heading->appendChild(new HtmlInline('</a>'));
+
+            $paragraph->detach();
+
+            $walker->resumeAt($heading->next());
+        }
+    }
+}

app/Markdown/GithubFlavoredMarkdownConverter.php

@@ -2,25 +2,19 @@
 
 namespace App\Markdown;
 
-use Illuminate\Support\Str;
+use Laravel\Unfenced\UnfencedExtension;
+use League\CommonMark\Environment\Environment;
+use League\CommonMark\Environment\EnvironmentInterface;
+use League\CommonMark\Event\DocumentParsedEvent;
+use League\CommonMark\Extension\Attributes\AttributesExtension;
 use League\CommonMark\Extension\Autolink\AutolinkExtension;
+use League\CommonMark\Extension\CommonMark\CommonMarkCoreExtension;
+use League\CommonMark\Extension\CommonMark\Node\Block\BlockQuote;
 use League\CommonMark\Extension\Strikethrough\StrikethroughExtension;
 use League\CommonMark\Extension\Table\TableExtension;
 use League\CommonMark\Extension\TaskList\TaskListExtension;
 use League\CommonMark\MarkdownConverter;
-use League\CommonMark\Environment\Environment;
-use App\Markdown\GithubFlavoredMarkdownExtension;
-use Illuminate\Support\Facades\Vite;
-use League\CommonMark\Node\Node;
-use League\CommonMark\Renderer\ChildNodeRendererInterface;
-use League\CommonMark\Util\HtmlElement;
 use Torchlight\Commonmark\V2\TorchlightExtension;
-use Laravel\Unfenced\UnfencedExtension;
-use League\CommonMark\Environment\EnvironmentInterface;
-use League\CommonMark\Extension\Attributes\AttributesExtension;
-use League\CommonMark\Extension\CommonMark\CommonMarkCoreExtension;
-use League\CommonMark\Extension\CommonMark\Node\Block\BlockQuote;
-use League\CommonMark\Renderer\NodeRendererInterface;
 
 /**
  * Converts GitHub Flavored Markdown to HTML.
@@ -44,7 +38,8 @@ public function __construct(array $config = [])
         $environment->addExtension(new AttributesExtension());
         $environment->addExtension(new TorchlightExtension());
 
-        $environment->addRenderer(BlockQuote::class, new BlockQuoteRenderer());
+        $environment->addRenderer(BlockQuote::class, new BlockQuoteRenderer);
+        $environment->addEventListener(DocumentParsedEvent::class, new ConfigureHeadingLinks);
 
         parent::__construct($environment);
     }