LibWeb: Add DOM::Node::parent_or_shadow_host()

This is useful when you want to traverse across shadow boundaries.

2 files changed, 10 insertions, 0 deletions

diff --git a/Userland/Libraries/LibWeb/DOM/Node.cpp b/Userland/Libraries/LibWeb/DOM/Node.cpp
index 5d0125d9e7..26204538bc 100644
--- a/Userland/Libraries/LibWeb/DOM/Node.cpp
+++ b/Userland/Libraries/LibWeb/DOM/Node.cpp
@@ -259,4 +259,11 @@ void Node::inserted_into(Node&)
     set_needs_style_update(true);
 }
 
+ParentNode* Node::parent_or_shadow_host()
+{
+    if (is<ShadowRoot>(*this))
+        return downcast<ShadowRoot>(*this).host();
+    return downcast<ParentNode>(parent());
+}
+
 }
diff --git a/Userland/Libraries/LibWeb/DOM/Node.h b/Userland/Libraries/LibWeb/DOM/Node.h
index a62c220fe1..4b1797e0ff 100644
--- a/Userland/Libraries/LibWeb/DOM/Node.h
+++ b/Userland/Libraries/LibWeb/DOM/Node.h
@@ -57,6 +57,9 @@ public:
     using TreeNode<Node>::ref;
     using TreeNode<Node>::unref;
 
+    ParentNode* parent_or_shadow_host();
+    const ParentNode* parent_or_shadow_host() const { return const_cast<Node*>(this)->parent_or_shadow_host(); }
+
     // ^EventTarget
     virtual void ref_event_target() final { ref(); }
     virtual void unref_event_target() final { unref(); }