node: add replaceChild method

Signed-off-by: Francis Bouvier <francis.bouvier@gmail.com>

src/dom/node.zig

@@ -173,6 +173,11 @@ pub const Node = struct {
         const res = parser.nodeRemoveChild(self, child);
         return Node.toInterface(res);
     }
+
+    pub fn _replaceChild(self: *parser.Node, new_child: *parser.Node, old_child: *parser.Node) Union {
+        const res = parser.nodeReplaceChild(self, new_child, old_child);
+        return Node.toInterface(res);
+    }
 };
 
 pub const Types = generate.Tuple(.{
@@ -349,4 +354,10 @@ pub fn testExecFn(
         .{ .src = "content.lastChild.__proto__.constructor.name !== 'HTMLHeadingElement'", .ex = "true" },
     };
     try checkCases(js_env, &node_remove_child);
+
+    var node_replace_child = [_]Case{
+        .{ .src = "let replace = document.createElement('div')", .ex = "undefined" },
+        .{ .src = "link.replaceChild(replace, insertBefore) !== undefined", .ex = "true" },
+    };
+    try checkCases(js_env, &node_replace_child);
 }

src/netsurf.zig

@@ -383,6 +383,12 @@ pub fn nodeRemoveChild(node: *Node, child: *Node) *Node {
     return res.?;
 }
 
+pub fn nodeReplaceChild(node: *Node, new_child: *Node, old_child: *Node) *Node {
+    var res: ?*Node = undefined;
+    _ = nodeVtable(node).dom_node_replace_child.?(node, new_child, old_child, &res);
+    return res.?;
+}
+
 // CharacterData
 pub const CharacterData = c.dom_characterdata;