events: add stop propagation flag to Event.stopImmediatePropagation

Spec mention stopImmediatePropagation should set both flags:
"stop propagation" and "stop immediate propagation".
So the second is not supported by Node.js as there is no
hierarchy and bubbling,
but the flags are both present as well as stopPropagation.
It would makes sense to follow specs on that.

Refs: https://dom.spec.whatwg.org/#dom-event-stopimmediatepropagation
PR-URL: nodejs#39463
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

lib/internal/event_target.js

@@ -168,6 +168,10 @@ class Event {
   stopImmediatePropagation() {
     if (!isEvent(this))
       throw new ERR_INVALID_THIS('Event');
+    // Spec mention "stopImmediatePropagation should set both "stop propagation"
+    // and "stop immediate propagation" flags"
+    // cf: from https://dom.spec.whatwg.org/#dom-event-stopimmediatepropagation
+    this.stopPropagation();
     this[kStop] = true;
   }
 

test/parallel/test-eventtarget.js

@@ -345,7 +345,9 @@ let asyncTest = Promise.resolve();
 {
   const target = new EventTarget();
   const event = new Event('foo');
+  strictEqual(event.cancelBubble, false);
   event.stopImmediatePropagation();
+  strictEqual(event.cancelBubble, true);
   target.addEventListener('foo', common.mustNotCall());
   target.dispatchEvent(event);
 }