MouseEvent: fix pageX/Y and offsetX/Y during dispatch

lib/jsdom/living/events/MouseEvent-impl.js

@@ -5,7 +5,6 @@ const EventModifierMixinImpl = require("./EventModifierMixin-impl").implementati
 const UIEventImpl = require("./UIEvent-impl").implementation;
 
 const MouseEventInit = require("../generated/MouseEventInit");
-const { wrapperForImpl } = require("../generated/utils");
 
 class MouseEventImpl extends UIEventImpl {
   get x() {
@@ -15,29 +14,19 @@ class MouseEventImpl extends UIEventImpl {
     return this.clientY;
   }
   get pageX() {
-    if (this._dispatchFlag) {
-      return 0;
-    }
-    const offset = wrapperForImpl(this.view)?.scrollX || 0;
-    return offset + this.clientX;
+    // TODO: consider dispatch flag and return page-relative event coordinate once layout is supported
+    return this.clientX; // TODO: add horizontal scroll offset once jsdom implements scrolling support
   }
   get pageY() {
-    if (this._dispatchFlag) {
-      return 0;
-    }
-    const offset = wrapperForImpl(this.view)?.scrollY || 0;
-    return offset + this.clientY;
+    // TODO: consider dispatch flag and return page-relative event coordinate once layout is supported
+    return this.clientY; // TODO: add vertical scroll offset once jsdom implements scrolling support
   }
   get offsetX() {
-    if (this._dispatchFlag) {
-      return 0;
-    }
+    // TODO: consider dispatch flag and return target-relative event coordinate once layout is supported
     return this.pageX;
   }
   get offsetY() {
-    if (this._dispatchFlag) {
-      return 0;
-    }
+    // TODO: consider dispatch flag and return target-relative event coordinate once layout is supported
     return this.pageY;
   }
 

test/web-platform-tests/to-upstream/html/editing/activation/click-event-properties.html

@@ -91,19 +91,30 @@
 }, "clicking using click() should produce an event object with the correct MouseEventInit values");
 
 test(() => {
-  window.scrollX = 10;
-  window.scrollY = 20;
   const e = new MouseEvent("click", {
     clientX: 1, clientY: 2, view: window
   });
   assert_equals(e.x, 1);
   assert_equals(e.y, 2);
-  assert_equals(e.pageX, 11);
-  assert_equals(e.pageY, 22);
-  assert_equals(e.offsetX, 11);
-  assert_equals(e.offsetY, 22);
+  assert_equals(e.pageX, 1);
+  assert_equals(e.pageY, 2);
+  assert_equals(e.offsetX, 1);
+  assert_equals(e.offsetY, 2);
 }, "MouseEvent should provide the correct computed values when the dispatch flag is not set");
 
+async_test(t => {
+  const element = document.documentElement; // dispatch against something at the origin (0,0) so it passes in browsers
+  element.addEventListener("click", t.step_func_done(e => {
+    assert_equals(e.pageX, 1);
+    assert_equals(e.pageY, 2);
+    assert_equals(e.offsetX, 1);
+    assert_equals(e.offsetY, 2);
+  }));
+  element.dispatchEvent(new MouseEvent("click", {
+    clientX: 1, clientY: 2, view: window
+  }));
+}, "MouseEvent should provide the correct computed values when the dispatch flag is set");
+
 test(() => {
   const e = new MouseEvent("click", {
     screenX: 1.5, screenY: 2.5, clientX: 3.5, clientY: 4.5
@@ -121,6 +132,5 @@
   assert_equals(e.screenY, 2);
   assert_equals(e.clientX, 3);
   assert_equals(e.clientY, 4);
-
 }, "MouseEvent.initMouseEvent should convert doubles to longs");
 </script>