NodeList index fix + Node.childNode fix

An index out of range request to a nodelist , e.g. childNodes[1000] now properly
returns a error.NotHandled error, which is given to v8 as a non-intercepted
property.

When a ChildNode node list is created from Node.childNode, we store the *Node
rather than its children. ChildNode is meant to be live, so if the node's
children changes, we should capture that.

src/browser/tests/node/child_nodes.html

@@ -22,6 +22,8 @@
   testing.expectEqual(undefined, children[-1]);
 
   testing.expectEqual(['p1', 'p2'], Array.from(children).map((n) => n.id));
+
+  testing.expectEqual(false, 10 in children);
 </script>
 
 <script id=values>

src/browser/webapi/Node.zig

@@ -249,8 +249,8 @@ pub fn appendChild(self: *Node, child: *Node, page: *Page) !*Node {
     return child;
 }
 
-pub fn childNodes(self: *const Node, page: *Page) !*collections.ChildNodes {
-    return collections.ChildNodes.init(self._children, page);
+pub fn childNodes(self: *Node, page: *Page) !*collections.ChildNodes {
+    return collections.ChildNodes.init(self, page);
 }
 
 pub fn getTextContent(self: *Node, writer: *std.Io.Writer) error{WriteFailed}!void {

src/browser/webapi/collections/ChildNodes.zig

@@ -30,18 +30,18 @@ _last_index: usize,
 _last_length: ?u32,
 _last_node: ?*std.DoublyLinkedList.Node,
 _cached_version: usize,
-_children: ?*Node.Children,
+_node: *Node,
 
 pub const KeyIterator = GenericIterator(Iterator, "0");
 pub const ValueIterator = GenericIterator(Iterator, "1");
 pub const EntryIterator = GenericIterator(Iterator, null);
 
-pub fn init(children: ?*Node.Children, page: *Page) !*ChildNodes {
+pub fn init(node: *Node, page: *Page) !*ChildNodes {
     return page._factory.create(ChildNodes{
+        ._node = node,
         ._last_index = 0,
         ._last_node = null,
         ._last_length = null,
-        ._children = children,
         ._cached_version = page.version,
     });
 }
@@ -52,7 +52,7 @@ pub fn length(self: *ChildNodes, page: *Page) !u32 {
             return cached_length;
         }
     }
-    const children = self._children orelse return 0;
+    const children = self._node._children orelse return 0;
 
     // O(N)
     const len = children.len();
@@ -86,7 +86,7 @@ pub fn getAtIndex(self: *ChildNodes, index: usize, page: *Page) !?*Node {
 }
 
 pub fn first(self: *const ChildNodes) ?*std.DoublyLinkedList.Node {
-    return &(self._children orelse return null).first()._child_link;
+    return &(self._node._children orelse return null).first()._child_link;
 }
 
 pub fn keys(self: *ChildNodes, page: *Page) !*KeyIterator {

src/browser/webapi/collections/NodeList.zig

@@ -53,6 +53,10 @@ pub fn length(self: *NodeList, page: *Page) !u32 {
     };
 }
 
+pub fn indexedGet(self: *NodeList, index: usize, page: *Page) !*Node {
+    return try self.getAtIndex(index, page) orelse return error.NotHandled;
+}
+
 pub fn getAtIndex(self: *NodeList, index: usize, page: *Page) !?*Node {
     return switch (self.data) {
         .child_nodes => |impl| impl.getAtIndex(index, page),
@@ -121,7 +125,7 @@ pub const JsApi = struct {
     };
 
     pub const length = bridge.accessor(NodeList.length, null, .{});
-    pub const @"[]" = bridge.indexed(NodeList.getAtIndex, .{ .null_as_undefined = true });
+    pub const @"[]" = bridge.indexed(NodeList.indexedGet, .{ .null_as_undefined = true });
     pub const item = bridge.function(NodeList.getAtIndex, .{});
     pub const keys = bridge.function(NodeList.keys, .{});
     pub const values = bridge.function(NodeList.values, .{});