feat: add headingIds field method

src/index.php

@@ -0,0 +1,36 @@
+<?php
+
+use Kirby\Content\Field;
+use Kirby\Toolkit\Dom;
+use Kirby\Toolkit\Str;
+
+Kirby::plugin('volkmann-design-code/kirby-utils', [
+    'fieldMethods' => [
+        /**
+         * Add IDs to headings in a field
+         */
+        'headingIds' => function (Field $field): Field {
+            if ($field->isNotEmpty() === true) {
+                $dom        = new Dom($field->value);
+                $levels = [
+                    'h1',
+                    'h2',
+                    'h3',
+                    'h4',
+                    'h5',
+                    'h6',
+                ];
+                $query = '//*[self::' . implode(' or self::', $levels) . ']';
+                $elements   = $dom->query($query);
+
+                foreach ($elements as $element) {
+                    $element->setAttribute('id', Str::slug($element->nodeValue));
+                }
+
+                $field->value = $dom->toString();
+            }
+
+            return $field;
+        },
+    ],
+]);