From 3d32759030e11f9c065e37a6569220f8c5300c1b Mon Sep 17 00:00:00 2001
From: Karl Seguin <k@openmymind.io>
Date: Thu, 12 Feb 2026 12:39:07 +0800
Subject: [PATCH] Allow node.contains(null) (false), per spec

---
 src/browser/tests/node/node.html | 13 +++++++++++++
 src/browser/webapi/Node.zig      |  4 +++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/browser/tests/node/node.html b/src/browser/tests/node/node.html
index 72c51748..b6e628e9 100644
--- a/src/browser/tests/node/node.html
+++ b/src/browser/tests/node/node.html
@@ -210,3 +210,16 @@
   testing.expectEqual('HTMLDivElement', disconnectedChild.getRootNode().__proto__.constructor.name);
   testing.expectEqual('HTMLDivElement', disconnectedChild.getRootNode({ composed: true }).__proto__.constructor.name);
 </script>
+
+<div id=contains><div id=other></div></div>
+<script id=contains>
+  {
+    const d1 = $('#contains');
+    const d2 = $('#other');
+    testing.expectEqual(false, d1.contains(null));
+    testing.expectEqual(true, d1.contains(d1));
+    testing.expectEqual(false, d2.contains(d1));
+    testing.expectEqual(true, d1.contains(d2));
+    testing.expectEqual(false, d1.contains(p1));
+  }
+</script>
diff --git a/src/browser/webapi/Node.zig b/src/browser/webapi/Node.zig
index 7482e042..b82f7862 100644
--- a/src/browser/webapi/Node.zig
+++ b/src/browser/webapi/Node.zig
@@ -413,7 +413,9 @@ pub fn getRootNode(self: *Node, opts_: ?GetRootNodeOpts) *Node {
     return root;
 }
 
-pub fn contains(self: *const Node, child: *const Node) bool {
+pub fn contains(self: *const Node, child_: ?*const Node) bool {
+    const child = child_ orelse return false;
+
     if (self == child) {
         // yes, this is correct
         return true;