From ae9a11da53a6fd6be516e4217a03f7ef654f397f Mon Sep 17 00:00:00 2001
From: egrs <egrs@users.noreply.github.com>
Date: Tue, 17 Feb 2026 12:52:44 +0100
Subject: [PATCH] implement MouseEvent.buttons property

Add the `buttons` read-only property to MouseEvent as specified by
the W3C UI Events spec (unsigned short bitmask of currently pressed
buttons). Propagate the field through PointerEvent and WheelEvent
constructors which inherit from MouseEvent.
---
 src/browser/tests/event/mouse.html        |  4 +++-
 src/browser/webapi/event/MouseEvent.zig   | 10 ++++++++--
 src/browser/webapi/event/PointerEvent.zig |  1 +
 src/browser/webapi/event/WheelEvent.zig   |  1 +
 4 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/src/browser/tests/event/mouse.html b/src/browser/tests/event/mouse.html
index 896ba62b..83fc4045 100644
--- a/src/browser/tests/event/mouse.html
+++ b/src/browser/tests/event/mouse.html
@@ -10,11 +10,13 @@
   testing.expectEqual(0, event.clientY);
   testing.expectEqual(0, event.screenX);
   testing.expectEqual(0, event.screenY);
+  testing.expectEqual(0, event.buttons);
 </script>
 
 <script id=parameters>
-  let new_event = new MouseEvent('click', { 'button': 0, 'clientX': 10, 'clientY': 20, screenX: 200, screenY: 500 });
+  let new_event = new MouseEvent('click', { 'button': 0, 'clientX': 10, 'clientY': 20, screenX: 200, screenY: 500, buttons: 5 });
   testing.expectEqual(0, new_event.button);
+  testing.expectEqual(5, new_event.buttons);
   testing.expectEqual(10, new_event.x);
   testing.expectEqual(20, new_event.y);
   testing.expectEqual(10, new_event.pageX);
diff --git a/src/browser/webapi/event/MouseEvent.zig b/src/browser/webapi/event/MouseEvent.zig
index a687aeaf..3997140d 100644
--- a/src/browser/webapi/event/MouseEvent.zig
+++ b/src/browser/webapi/event/MouseEvent.zig
@@ -48,7 +48,7 @@ _proto: *UIEvent,
 
 _alt_key: bool,
 _button: MouseButton,
-// TODO: _buttons
+_buttons: u16,
 _client_x: f64,
 _client_y: f64,
 _ctrl_key: bool,
@@ -69,7 +69,7 @@ pub const MouseEventOptions = struct {
     altKey: bool = false,
     metaKey: bool = false,
     button: i32 = 0,
-    // TODO: buttons
+    buttons: u16 = 0,
     relatedTarget: ?*EventTarget = null,
 };
 
@@ -100,6 +100,7 @@ pub fn init(typ: []const u8, _opts: ?Options, page: *Page) !*MouseEvent {
             ._alt_key = opts.altKey,
             ._meta_key = opts.metaKey,
             ._button = std.meta.intToEnum(MouseButton, opts.button) catch return error.TypeError,
+            ._buttons = opts.buttons,
             ._related_target = opts.relatedTarget,
         },
     );
@@ -137,6 +138,10 @@ pub fn getButton(self: *const MouseEvent) u8 {
     return @intFromEnum(self._button);
 }
 
+pub fn getButtons(self: *const MouseEvent) u16 {
+    return self._buttons;
+}
+
 pub fn getClientX(self: *const MouseEvent) f64 {
     return self._client_x;
 }
@@ -193,6 +198,7 @@ pub const JsApi = struct {
     pub const constructor = bridge.constructor(MouseEvent.init, .{});
     pub const altKey = bridge.accessor(getAltKey, null, .{});
     pub const button = bridge.accessor(getButton, null, .{});
+    pub const buttons = bridge.accessor(getButtons, null, .{});
     pub const clientX = bridge.accessor(getClientX, null, .{});
     pub const clientY = bridge.accessor(getClientY, null, .{});
     pub const ctrlKey = bridge.accessor(getCtrlKey, null, .{});
diff --git a/src/browser/webapi/event/PointerEvent.zig b/src/browser/webapi/event/PointerEvent.zig
index 97f03eb8..df388186 100644
--- a/src/browser/webapi/event/PointerEvent.zig
+++ b/src/browser/webapi/event/PointerEvent.zig
@@ -103,6 +103,7 @@ pub fn init(typ: []const u8, _opts: ?Options, page: *Page) !*PointerEvent {
             ._alt_key = opts.altKey,
             ._meta_key = opts.metaKey,
             ._button = std.meta.intToEnum(MouseEvent.MouseButton, opts.button) catch return error.TypeError,
+            ._buttons = opts.buttons,
             ._related_target = opts.relatedTarget,
         },
         PointerEvent{
diff --git a/src/browser/webapi/event/WheelEvent.zig b/src/browser/webapi/event/WheelEvent.zig
index 665e1d49..f1aadba7 100644
--- a/src/browser/webapi/event/WheelEvent.zig
+++ b/src/browser/webapi/event/WheelEvent.zig
@@ -70,6 +70,7 @@ pub fn init(typ: []const u8, _opts: ?Options, page: *Page) !*WheelEvent {
             ._alt_key = opts.altKey,
             ._meta_key = opts.metaKey,
             ._button = std.meta.intToEnum(MouseEvent.MouseButton, opts.button) catch return error.TypeError,
+            ._buttons = opts.buttons,
             ._related_target = opts.relatedTarget,
         },
         WheelEvent{