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benjamingrdanielleadams
benjamingr
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danielleadams
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events: support signal in EventTarget
PR-URL: #36258Fixes: #36073 Reviewed-By: James M Snell <jasnell@gmail.com>
1 parent f317bba commit 855a85c

3 files changed

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‎lib/internal/event_target.js‎

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Original file line numberDiff line numberDiff line change
@@ -200,10 +200,12 @@ class Listener {
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previous.next=this;
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this.previous=previous;
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this.listener=listener;
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// TODO(benjamingr) these 4 can be 'flags' to save 3 slots
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this.once=once;
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this.capture=capture;
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this.passive=passive;
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this.isNodeStyleListener=isNodeStyleListener;
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this.removed=false;
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this.callback=
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typeoflistener==='function' ?
@@ -220,6 +222,7 @@ class Listener {
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this.previous.next=this.next;
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if(this.next!==undefined)
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this.next.previous=this.previous;
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this.removed=true;
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}
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}
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@@ -269,6 +272,7 @@ class EventTarget {
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once,
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capture,
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passive,
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signal,
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isNodeStyleListener
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}=validateEventListenerOptions(options);
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@@ -286,6 +290,17 @@ class EventTarget {
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}
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type=String(type);
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if(signal){
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if(signal.aborted){
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returnfalse;
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}
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// TODO(benjamingr) make this weak somehow? ideally the signal would
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// not prevent the event target from GC.
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signal.addEventListener('abort',()=>{
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this.removeEventListener(type,listener,options);
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},{once: true});
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}
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letroot=this[kEvents].get(type);
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if(root===undefined){
@@ -382,6 +397,12 @@ class EventTarget {
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// Cache the next item in case this iteration removes the current one
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next=handler.next;
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if(handler.removed){
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// Deal with the case an event is removed while event handlers are
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// Being processed (removeEventListener called from a listener)
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handler=next;
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continue;
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}
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if(handler.once){
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handler.remove();
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root.size--;
@@ -550,6 +571,7 @@ function validateEventListenerOptions(options) {
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once: Boolean(options.once),
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capture: Boolean(options.capture),
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passive: Boolean(options.passive),
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signal: options.signal,
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isNodeStyleListener: Boolean(options[kIsNodeStyleListener])
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};
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}

‎test/parallel/test-eventtarget-whatwg-signal.js‎

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@@ -0,0 +1,155 @@
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'use strict';
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require('../common');
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const{
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strictEqual,
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}=require('assert');
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// Manually ported from: wpt@dom/events/AddEventListenerOptions-signal.any.js
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{
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// Passing an AbortSignal to addEventListener does not prevent
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// removeEventListener
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letcount=0;
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functionhandler(){
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count++;
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}
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constet=newEventTarget();
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constcontroller=newAbortController();
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et.addEventListener('test',handler,{signal: controller.signal});
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et.dispatchEvent(newEvent('test'));
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strictEqual(count,1,'Adding a signal still adds a listener');
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et.dispatchEvent(newEvent('test'));
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strictEqual(count,2,'The listener was not added with the once flag');
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controller.abort();
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et.dispatchEvent(newEvent('test'));
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strictEqual(count,2,'Aborting on the controller removes the listener');
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et.addEventListener('test',handler,{signal: controller.signal});
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et.dispatchEvent(newEvent('test'));
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strictEqual(count,2,'Passing an aborted signal never adds the handler');
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}
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{
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// Passing an AbortSignal to addEventListener works with the once flag
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letcount=0;
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functionhandler(){
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count++;
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}
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constet=newEventTarget();
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constcontroller=newAbortController();
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et.addEventListener('test',handler,{signal: controller.signal});
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et.removeEventListener('test',handler);
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et.dispatchEvent(newEvent('test'));
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strictEqual(count,0,'The listener was still removed');
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}
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{
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// Removing a once listener works with a passed signal
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letcount=0;
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functionhandler(){
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count++;
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}
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constet=newEventTarget();
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constcontroller=newAbortController();
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constoptions={signal: controller.signal,once: true};
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et.addEventListener('test',handler,options);
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controller.abort();
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et.dispatchEvent(newEvent('test'));
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strictEqual(count,0,'The listener was still removed');
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}
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{
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letcount=0;
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functionhandler(){
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count++;
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}
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constet=newEventTarget();
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constcontroller=newAbortController();
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constoptions={signal: controller.signal,once: true};
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et.addEventListener('test',handler,options);
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et.removeEventListener('test',handler);
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et.dispatchEvent(newEvent('test'));
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strictEqual(count,0,'The listener was still removed');
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}
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{
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// Passing an AbortSignal to multiple listeners
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letcount=0;
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functionhandler(){
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count++;
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}
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constet=newEventTarget();
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constcontroller=newAbortController();
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constoptions={signal: controller.signal,once: true};
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et.addEventListener('first',handler,options);
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et.addEventListener('second',handler,options);
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controller.abort();
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et.dispatchEvent(newEvent('first'));
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et.dispatchEvent(newEvent('second'));
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strictEqual(count,0,'The listener was still removed');
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}
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{
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// Passing an AbortSignal to addEventListener works with the capture flag
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letcount=0;
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functionhandler(){
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count++;
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}
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constet=newEventTarget();
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constcontroller=newAbortController();
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constoptions={signal: controller.signal,capture: true};
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et.addEventListener('test',handler,options);
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controller.abort();
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et.dispatchEvent(newEvent('test'));
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strictEqual(count,0,'The listener was still removed');
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}
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{
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// Aborting from a listener does not call future listeners
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letcount=0;
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functionhandler(){
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count++;
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}
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constet=newEventTarget();
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constcontroller=newAbortController();
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constoptions={signal: controller.signal};
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et.addEventListener('test',()=>{
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controller.abort();
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},options);
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et.addEventListener('test',handler,options);
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et.dispatchEvent(newEvent('test'));
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strictEqual(count,0,'The listener was still removed');
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}
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{
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// Adding then aborting a listener in another listener does not call it
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letcount=0;
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functionhandler(){
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count++;
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}
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constet=newEventTarget();
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constcontroller=newAbortController();
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et.addEventListener('test',()=>{
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et.addEventListener('test',handler,{signal: controller.signal});
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controller.abort();
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},{signal: controller.signal});
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et.dispatchEvent(newEvent('test'));
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strictEqual(count,0,'The listener was still removed');
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}
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{
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// Aborting from a nested listener should remove it
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constet=newEventTarget();
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constac=newAbortController();
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letcount=0;
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et.addEventListener('foo',()=>{
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et.addEventListener('foo',()=>{
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count++;
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if(count>5)ac.abort();
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et.dispatchEvent(newEvent('foo'));
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},{signal: ac.signal});
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et.dispatchEvent(newEvent('foo'));
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},{once: true});
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et.dispatchEvent(newEvent('foo'));
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}

‎test/parallel/test-eventtarget.js‎

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Original file line numberDiff line numberDiff line change
@@ -532,3 +532,12 @@ let asyncTest = Promise.resolve();
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target.dispatchEvent(newEvent('foo'));
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deepStrictEqual(output,[1,2,3,4]);
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}
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{
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constet=newEventTarget();
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constlistener=common.mustNotCall();
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et.addEventListener('foo',common.mustCall((e)=>{
539+
et.removeEventListener('foo',listener);
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}));
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et.addEventListener('foo',listener);
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et.dispatchEvent(newEvent('foo'));
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}

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