From 5f09d1878deeda64ef0c4ee171f80726a6a60ea5 Mon Sep 17 00:00:00 2001
From: Mason Freed <masonf@chromium.org>
Date: Fri, 27 Jan 2023 17:39:12 -0800
Subject: [PATCH] Update popover post-toggle event naming and behavior

This CL updates the post-toggle event in the following ways:
 1. Rename the 'aftertoggle' event to 'toggle'.
 2. Rename PopoverToggleEvent to ToggleEvent.
 3. Rename the currentState attribute to oldState.
 4. Add event coalescing behavior. If two transitions occur before the
    first 'toggle' event has been fired, cancel the first event and
    queue a replacement that has oldState === newState.

These changes were driven by the corresponding changes to the spec PR:
  https://github.com/whatwg/html/pull/8717

Bug: 1307772
Change-Id: Iabc5a9093d7cef3bbd6e54e488d8e571c51ea568
---
 .../popovers/idlharness.tentative.html        |  12 +-
 .../popovers/popover-events.tentative.html    | 120 ++++++++++---
 .../toggleevent-interface.tentative.html      | 164 +++++++++---------
 interfaces/popover.tentative.idl              |  10 +-
 4 files changed, 186 insertions(+), 120 deletions(-)

diff --git a/html/semantics/popovers/idlharness.tentative.html b/html/semantics/popovers/idlharness.tentative.html
index d1a258bb4ad3ac3..1cab891261cfd46 100644
--- a/html/semantics/popovers/idlharness.tentative.html
+++ b/html/semantics/popovers/idlharness.tentative.html
@@ -41,12 +41,12 @@
         'document.getElementById("b3")',
       ],
       BeforeToggleEvent: [
-        'new PopoverToggleEvent("beforetoggle")',
-        'new PopoverToggleEvent("beforetoggle", {currentState: "open"})',
-        'new PopoverToggleEvent("beforetoggle", {currentState: "open",newState: "open"})',
-        'new PopoverToggleEvent("aftertoggle")',
-        'new PopoverToggleEvent("aftertoggle", {currentState: "open"})',
-        'new PopoverToggleEvent("aftertoggle", {currentState: "open",newState: "open"})',
+        'new ToggleEvent("beforetoggle")',
+        'new ToggleEvent("beforetoggle", {oldState: "open"})',
+        'new ToggleEvent("beforetoggle", {oldState: "open",newState: "open"})',
+        'new ToggleEvent("toggle")',
+        'new ToggleEvent("toggle", {oldState: "open"})',
+        'new ToggleEvent("toggle", {oldState: "open",newState: "open"})',
       ],
     });
   }
diff --git a/html/semantics/popovers/popover-events.tentative.html b/html/semantics/popovers/popover-events.tentative.html
index b96a0f5a53f489d..b299424570024c8 100644
--- a/html/semantics/popovers/popover-events.tentative.html
+++ b/html/semantics/popovers/popover-events.tentative.html
@@ -10,6 +10,13 @@
 <div popover>Popover</div>
 
 <script>
+function getPopoverAndSignal(t) {
+  const popover = document.querySelector('[popover]');
+  const controller = new AbortController();
+  const signal = controller.signal;
+  t.add_cleanup(() => controller.abort());
+  return {popover, signal};
+}
 window.onload = () => {
   for(const method of ["listener","attribute"]) {
     promise_test(async t => {
@@ -22,52 +29,48 @@
       function listener(e) {
         if (e.type === "beforetoggle") {
           if (e.newState === "open") {
-            assert_equals(e.currentState,"closed",'The "beforetoggle" event should be fired before the popover is open');
+            ++showCount;
+            assert_equals(e.oldState,"closed",'The "beforetoggle" event should be fired before the popover is open');
             assert_true(e.target.matches(':closed'),'The popover should be in the :closed state when the opening event fires.');
             assert_false(e.target.matches(':open'),'The popover should *not* be in the :open state when the opening event fires.');
-            ++showCount;
           } else {
+            ++hideCount;
             assert_equals(e.newState,"closed",'Popover toggleevent states should be "open" and "closed"');
-            assert_equals(e.currentState,"open",'The "beforetoggle" event should be fired before the popover is closed')
+            assert_equals(e.oldState,"open",'The "beforetoggle" event should be fired before the popover is closed')
             assert_true(e.target.matches(':open'),'The popover should be in the :open state when the hiding event fires.');
             assert_false(e.target.matches(':closed'),'The popover should *not* be in the :closed state when the hiding event fires.');
-            ++hideCount;
           }
         } else {
-          assert_equals(e.type,"aftertoggle",'Popover events should be "beforetoggle" and "aftertoggle"')
+          assert_equals(e.type,"toggle",'Popover events should be "beforetoggle" and "toggle"')
           if (e.newState === "open") {
-            assert_equals(e.currentState,"open",'Aftertoggle should be fired after the popover is open');
+            ++afterShowCount;
             if (document.body.contains(e.target)) {
               assert_true(e.target.matches(':open'),'The popover should be in the :open state when the after opening event fires.');
               assert_false(e.target.matches(':closed'),'The popover should *not* be in the :closed state when the after opening event fires.');
             }
-            ++afterShowCount;
           } else {
+            ++afterHideCount;
             assert_equals(e.newState,"closed",'Popover toggleevent states should be "open" and "closed"');
-            assert_equals(e.currentState,"closed",'Aftertoggle should be fired after the popover is closed');
             assert_true(e.target.matches(':closed'),'The popover should be in the :closed state when the after hiding event fires.');
             assert_false(e.target.matches(':open'),'The popover should *not* be in the :open state when the after hiding event fires.');
-            ++afterHideCount;
           }
-          e.preventDefault(); // "aftertoggle" should not be cancelable.
+          e.preventDefault(); // "toggle" should not be cancelable.
         }
       };
       switch (method) {
         case "listener":
-          const controller = new AbortController();
-          const signal = controller.signal;
-          t.add_cleanup(() => controller.abort());
+          const {signal} = getPopoverAndSignal(t);
           // These events bubble.
           document.addEventListener('beforetoggle', listener, {signal});
-          document.addEventListener('aftertoggle', listener, {signal});
+          document.addEventListener('toggle', listener, {signal});
           break;
         case "attribute":
           assert_false(popover.hasAttribute('onbeforetoggle'));
           t.add_cleanup(() => popover.removeAttribute('onbeforetoggle'));
           popover.onbeforetoggle = listener;
-          assert_false(popover.hasAttribute('onaftertoggle'));
-          t.add_cleanup(() => popover.removeAttribute('onaftertoggle'));
-          popover.onaftertoggle = listener;
+          assert_false(popover.hasAttribute('ontoggle'));
+          t.add_cleanup(() => popover.removeAttribute('ontoggle'));
+          popover.ontoggle = listener;
           break;
         default: assert_unreached();
       }
@@ -82,7 +85,7 @@
       assert_equals(0,afterShowCount);
       assert_equals(0,afterHideCount);
       await waitForRender();
-      assert_equals(1,afterShowCount,'aftertoggle show is fired asynchronously');
+      assert_equals(1,afterShowCount,'toggle show is fired asynchronously');
       assert_equals(0,afterHideCount);
       assert_true(popover.matches(':open'));
       popover.hidePopover();
@@ -93,7 +96,7 @@
       assert_equals(0,afterHideCount);
       await waitForRender();
       assert_equals(1,afterShowCount);
-      assert_equals(1,afterHideCount,'aftertoggle hide is fired asynchronously');
+      assert_equals(1,afterHideCount,'toggle hide is fired asynchronously');
       // No additional events
       await waitForRender();
       await waitForRender();
@@ -106,10 +109,7 @@
   }
 
   promise_test(async t => {
-    const popover = document.querySelector('[popover]');
-    const controller = new AbortController();
-    const signal = controller.signal;
-    t.add_cleanup(() => controller.abort());
+    const {popover,signal} = getPopoverAndSignal(t);
     let cancel = true;
     popover.addEventListener('beforetoggle',(e) => {
       if (e.newState !== "open")
@@ -128,10 +128,7 @@
   }, 'The "beforetoggle" event is cancelable for the "opening" transition');
 
   promise_test(async t => {
-    const popover = document.querySelector('[popover]');
-    const controller = new AbortController();
-    const signal = controller.signal;
-    t.add_cleanup(() => {controller.abort();});
+    const {popover,signal} = getPopoverAndSignal(t);
     popover.addEventListener('beforetoggle',(e) => {
       assert_not_equals(e.newState,"closed",'The "beforetoggle" event was fired for the closing transition');
     }, {signal});
@@ -144,5 +141,74 @@
     await waitForRender(); // Check for async events also
     assert_false(popover.matches(':open'));
   }, 'The "beforetoggle" event is not fired for element removal');
+
+  promise_test(async t => {
+    const {popover,signal} = getPopoverAndSignal(t);
+    let events;
+    function resetEvents() {
+      events = {
+        singleShow: false,
+        singleHide: false,
+        coalescedShow: false,
+        coalescedHide: false,
+      };
+    }
+    function setEvent(type) {
+      assert_equals(events[type],false,'event repeated');
+      events[type] = true;
+    }
+    function assertOnly(type,msg) {
+      Object.keys(events).forEach(val => {
+        assert_equals(events[val],val===type,`${msg} (${val})`);
+      });
+    }
+    popover.addEventListener('toggle',(e) => {
+      switch (e.newState) {
+        case "open":
+          switch (e.oldState) {
+            case "open": setEvent('coalescedShow'); break;
+            case "closed": setEvent('singleShow'); break;
+            default: assert_unreached();
+          }
+          break;
+        case "closed":
+          switch (e.oldState) {
+            case "closed": setEvent('coalescedHide'); break;
+            case "open": setEvent('singleHide'); break;
+            default: assert_unreached();
+          }
+          break;
+        default: assert_unreached();
+      }
+    }, {signal});
+
+    resetEvents();
+    assertOnly('none');
+    assert_false(popover.matches(':open'));
+    popover.showPopover();
+    await waitForRender();
+    assert_true(popover.matches(':open'));
+    assertOnly('singleShow','Single event should have been fired, which is a "show"');
+
+    resetEvents();
+    popover.hidePopover();
+    popover.showPopover(); // Immediate re-show
+    await waitForRender();
+    assert_true(popover.matches(':open'));
+    assertOnly('coalescedShow','Single coalesced event should have been fired, which is a "show"');
+
+    resetEvents();
+    popover.hidePopover();
+    await waitForRender();
+    assertOnly('singleHide','Single event should have been fired, which is a "hide"');
+    assert_false(popover.matches(':open'));
+
+    resetEvents();
+    popover.showPopover();
+    popover.hidePopover(); // Immediate re-hide
+    await waitForRender();
+    assertOnly('coalescedHide','Single coalesced event should have been fired, which is a "hide"');
+    assert_false(popover.matches(':open'));
+  }, 'The "toggle" event is coalesced');
 };
 </script>
diff --git a/html/semantics/popovers/toggleevent-interface.tentative.html b/html/semantics/popovers/toggleevent-interface.tentative.html
index 4d437b0c0ad523c..45709458b00c466 100644
--- a/html/semantics/popovers/toggleevent-interface.tentative.html
+++ b/html/semantics/popovers/toggleevent-interface.tentative.html
@@ -7,200 +7,200 @@
 
 <script>
 test(function() {
-  var event = new PopoverToggleEvent("");
-  assert_true(event instanceof window.PopoverToggleEvent);
-}, "the event is an instance of PopoverToggleEvent");
+  var event = new ToggleEvent("");
+  assert_true(event instanceof window.ToggleEvent);
+}, "the event is an instance of ToggleEvent");
 
 test(function() {
-  var event = new PopoverToggleEvent("");
+  var event = new ToggleEvent("");
   assert_true(event instanceof window.Event);
 }, "the event inherts from Event");
 
 test(function() {
   assert_throws_js(TypeError, function() {
-    new PopoverToggleEvent();
+    new ToggleEvent();
   }, 'First argument (type) is required, so was expecting a TypeError.');
 }, 'Missing type argument');
 
 test(function() {
-  var event = new PopoverToggleEvent("test");
+  var event = new ToggleEvent("test");
   assert_equals(event.type, "test");
 }, "type argument is string");
 
 test(function() {
-  var event = new PopoverToggleEvent(null);
+  var event = new ToggleEvent(null);
   assert_equals(event.type, "null");
 }, "type argument is null");
 
 test(function() {
-  var event = new PopoverToggleEvent(undefined);
+  var event = new ToggleEvent(undefined);
   assert_equals(event.type, "undefined");
 }, "event type set to undefined");
 
 test(function() {
-  var event = new PopoverToggleEvent("test");
-  assert_equals(event.currentState, "");
-}, "currentState has default value of empty string");
+  var event = new ToggleEvent("test");
+  assert_equals(event.oldState, "");
+}, "oldState has default value of empty string");
 
 test(function() {
-  var event = new PopoverToggleEvent("test");
-  assert_readonly(event, "currentState", "readonly attribute value");
-}, "currentState is readonly");
+  var event = new ToggleEvent("test");
+  assert_readonly(event, "oldState", "readonly attribute value");
+}, "oldState is readonly");
 
 test(function() {
-  var event = new PopoverToggleEvent("test");
+  var event = new ToggleEvent("test");
   assert_equals(event.newState, "");
 }, "newState has default value of empty string");
 
 test(function() {
-  var event = new PopoverToggleEvent("test");
+  var event = new ToggleEvent("test");
   assert_readonly(event, "newState", "readonly attribute value");
 }, "newState is readonly");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", null);
-  assert_equals(event.currentState, "");
+  var event = new ToggleEvent("test", null);
+  assert_equals(event.oldState, "");
   assert_equals(event.newState, "");
-}, "PopoverToggleEventInit argument is null");
+}, "ToggleEventInit argument is null");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", undefined);
-  assert_equals(event.currentState, "");
+  var event = new ToggleEvent("test", undefined);
+  assert_equals(event.oldState, "");
   assert_equals(event.newState, "");
-}, "PopoverToggleEventInit argument is undefined");
+}, "ToggleEventInit argument is undefined");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {});
-  assert_equals(event.currentState, "");
+  var event = new ToggleEvent("test", {});
+  assert_equals(event.oldState, "");
   assert_equals(event.newState, "");
-}, "PopoverToggleEventInit argument is empty dictionary");
+}, "ToggleEventInit argument is empty dictionary");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {currentState: "sample"});
-  assert_equals(event.currentState, "sample");
-}, "currentState set to 'sample'");
+  var event = new ToggleEvent("test", {oldState: "sample"});
+  assert_equals(event.oldState, "sample");
+}, "oldState set to 'sample'");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {currentState: undefined});
-  assert_equals(event.currentState, "");
-}, "currentState set to undefined");
+  var event = new ToggleEvent("test", {oldState: undefined});
+  assert_equals(event.oldState, "");
+}, "oldState set to undefined");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {currentState: null});
-  assert_equals(event.currentState, "null");
-}, "currentState set to null");
+  var event = new ToggleEvent("test", {oldState: null});
+  assert_equals(event.oldState, "null");
+}, "oldState set to null");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {currentState: false});
-  assert_equals(event.currentState, "false");
-}, "currentState set to false");
+  var event = new ToggleEvent("test", {oldState: false});
+  assert_equals(event.oldState, "false");
+}, "oldState set to false");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {currentState: true});
-  assert_equals(event.currentState, "true");
-}, "currentState set to true");
+  var event = new ToggleEvent("test", {oldState: true});
+  assert_equals(event.oldState, "true");
+}, "oldState set to true");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {currentState: 0.5});
-  assert_equals(event.currentState, "0.5");
-}, "currentState set to a number");
+  var event = new ToggleEvent("test", {oldState: 0.5});
+  assert_equals(event.oldState, "0.5");
+}, "oldState set to a number");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {currentState: []});
-  assert_equals(event.currentState, "");
-}, "currentState set to []");
+  var event = new ToggleEvent("test", {oldState: []});
+  assert_equals(event.oldState, "");
+}, "oldState set to []");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {currentState: [1, 2, 3]});
-  assert_equals(event.currentState, "1,2,3");
-}, "currentState set to [1, 2, 3]");
+  var event = new ToggleEvent("test", {oldState: [1, 2, 3]});
+  assert_equals(event.oldState, "1,2,3");
+}, "oldState set to [1, 2, 3]");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {currentState: {sample: 0.5}});
-  assert_equals(event.currentState, "[object Object]");
-}, "currentState set to an object");
+  var event = new ToggleEvent("test", {oldState: {sample: 0.5}});
+  assert_equals(event.oldState, "[object Object]");
+}, "oldState set to an object");
 
 test(function() {
-  var event = new PopoverToggleEvent("test",
-      {currentState: {valueOf: function () { return 'sample'; }}});
-  assert_equals(event.currentState, "[object Object]");
-}, "currentState set to an object with a valueOf function");
+  var event = new ToggleEvent("test",
+      {oldState: {valueOf: function () { return 'sample'; }}});
+  assert_equals(event.oldState, "[object Object]");
+}, "oldState set to an object with a valueOf function");
 
 test(function() {
-  var eventInit = {currentState: "sample",newState: "sample2"};
-  var event = new PopoverToggleEvent("test", eventInit);
-  assert_equals(event.currentState, "sample");
+  var eventInit = {oldState: "sample",newState: "sample2"};
+  var event = new ToggleEvent("test", eventInit);
+  assert_equals(event.oldState, "sample");
   assert_equals(event.newState, "sample2");
-}, "PopoverToggleEventInit properties set value");
+}, "ToggleEventInit properties set value");
 
 test(function() {
-  var eventInit = {currentState: "open",newState: "closed"};
-  var event = new PopoverToggleEvent("beforetoggle", eventInit);
-  assert_equals(event.currentState, "open");
+  var eventInit = {oldState: "open",newState: "closed"};
+  var event = new ToggleEvent("beforetoggle", eventInit);
+  assert_equals(event.oldState, "open");
   assert_equals(event.newState, "closed");
-}, "PopoverToggleEventInit properties set value 2");
+}, "ToggleEventInit properties set value 2");
 
 test(function() {
-  var eventInit = {currentState: "closed",newState: "open"};
-  var event = new PopoverToggleEvent("aftertoggle", eventInit);
-  assert_equals(event.currentState, "closed");
+  var eventInit = {oldState: "closed",newState: "open"};
+  var event = new ToggleEvent("toggle", eventInit);
+  assert_equals(event.oldState, "closed");
   assert_equals(event.newState, "open");
-}, "PopoverToggleEventInit properties set value 3");
+}, "ToggleEventInit properties set value 3");
 
 test(function() {
-  var eventInit = {currentState: "open",newState: "open"};
-  var event = new PopoverToggleEvent("beforetoggle", eventInit);
-  assert_equals(event.currentState, "open");
+  var eventInit = {oldState: "open",newState: "open"};
+  var event = new ToggleEvent("beforetoggle", eventInit);
+  assert_equals(event.oldState, "open");
   assert_equals(event.newState, "open");
-}, "PopoverToggleEventInit properties set value 4");
+}, "ToggleEventInit properties set value 4");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {newState: "sample"});
+  var event = new ToggleEvent("test", {newState: "sample"});
   assert_equals(event.newState, "sample");
 }, "newState set to 'sample'");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {newState: undefined});
+  var event = new ToggleEvent("test", {newState: undefined});
   assert_equals(event.newState, "");
 }, "newState set to undefined");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {newState: null});
+  var event = new ToggleEvent("test", {newState: null});
   assert_equals(event.newState, "null");
 }, "newState set to null");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {newState: false});
+  var event = new ToggleEvent("test", {newState: false});
   assert_equals(event.newState, "false");
 }, "newState set to false");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {newState: true});
+  var event = new ToggleEvent("test", {newState: true});
   assert_equals(event.newState, "true");
 }, "newState set to true");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {newState: 0.5});
+  var event = new ToggleEvent("test", {newState: 0.5});
   assert_equals(event.newState, "0.5");
 }, "newState set to a number");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {newState: []});
+  var event = new ToggleEvent("test", {newState: []});
   assert_equals(event.newState, "");
 }, "newState set to []");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {newState: [1, 2, 3]});
+  var event = new ToggleEvent("test", {newState: [1, 2, 3]});
   assert_equals(event.newState, "1,2,3");
 }, "newState set to [1, 2, 3]");
 
 test(function() {
-  var event = new PopoverToggleEvent("test", {newState: {sample: 0.5}});
+  var event = new ToggleEvent("test", {newState: {sample: 0.5}});
   assert_equals(event.newState, "[object Object]");
 }, "newState set to an object");
 
 test(function() {
-  var event = new PopoverToggleEvent("test",
+  var event = new ToggleEvent("test",
       {newState: {valueOf: function () { return 'sample'; }}});
   assert_equals(event.newState, "[object Object]");
 }, "newState set to an object with a valueOf function");
diff --git a/interfaces/popover.tentative.idl b/interfaces/popover.tentative.idl
index bf23c7641d94e80..4e8c85f7dacb144 100644
--- a/interfaces/popover.tentative.idl
+++ b/interfaces/popover.tentative.idl
@@ -13,13 +13,13 @@ interface mixin PopoverTargetElement {
 HTMLInputElement includes PopoverTargetElement;
 HTMLButtonElement includes PopoverTargetElement;
 
-interface PopoverToggleEvent : Event {
-    constructor(DOMString type, optional PopoverToggleEventInit eventInitDict = {});
-    readonly attribute DOMString currentState;
+interface ToggleEvent : Event {
+    constructor(DOMString type, optional ToggleEventInit eventInitDict = {});
+    readonly attribute DOMString oldState;
     readonly attribute DOMString newState;
 };
 
-dictionary PopoverToggleEventInit : EventInit {
-    DOMString currentState = "";
+dictionary ToggleEventInit : EventInit {
+    DOMString oldState = "";
     DOMString newState = "";
 };