DOM: Test that some event listeners are passive by default

Follows whatwg/dom#1087
web-platform-tests · Jun 30, 2022 · f1c5bcd · f1c5bcd
1 parent ba22f22
commit f1c5bcd
Showing 1 changed file with 50 additions and 0 deletions.
diff --git a/dom/events/passive-by-default.html b/dom/events/passive-by-default.html
@@ -0,0 +1,50 @@
+<!DOCTYPE html>
+<title>Default passive event listeners on window, document, document element, body</title>
+<link rel="help" href="https://dom.spec.whatwg.org/#default-passive-value">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<body>
+  <div id="div"></div>
+<script>
+  function isListenerPassive(eventName, eventTarget, passive, expectPassive) {
+    test(() => {
+      let defaultPrevented = null;
+      let handler = event => {
+        event.preventDefault();
+        defaultPrevented = event.defaultPrevented;
+        eventTarget.removeEventListener(eventName, handler);
+      };
+      if (passive === 'omitted') {
+        eventTarget.addEventListener(eventName, handler);
+      } else {
+        eventTarget.addEventListener(eventName, handler, {passive});
+      }
+      let dispatchEventReturnValue = eventTarget.dispatchEvent(new Event(eventName, {cancelable: true}));
+      assert_equals(defaultPrevented, !expectPassive, 'defaultPrevented');
+      assert_equals(dispatchEventReturnValue, expectPassive, 'dispatchEvent() return value');
+    }, `${eventName} listener is ${expectPassive ? '' : 'non-'}passive ${passive === 'omitted' ? 'by default' : `with {passive:${passive}}`} for ${eventTarget.constructor.name}`);
+  }
+
+  const eventNames = {
+    touchstart: true,
+    touchmove: true,
+    wheel: true,
+    mousewheel: true,
+    touchend: false
+  };
+  const passiveEventTargets = [window, document, document.documentElement, document.body];
+  const div = document.getElementById('div');
+
+  for (const eventName in eventNames) {
+    for (const eventTarget of passiveEventTargets) {
+      isListenerPassive(eventName, eventTarget, 'omitted', eventNames[eventName]);
+      isListenerPassive(eventName, eventTarget, undefined, eventNames[eventName]);
+      isListenerPassive(eventName, eventTarget, false, false);
+      isListenerPassive(eventName, eventTarget, true, true);
+    }
+    isListenerPassive(eventName, div, 'omitted', false);
+    isListenerPassive(eventName, div, undefined, false);
+    isListenerPassive(eventName, div, false, false);
+    isListenerPassive(eventName, div, true, true);
+  }
+</script>