fix(zone.js): handle fetch with AbortSignal

fetch support AbortSignal, zone.js schedules a macroTask when fetch()

```
fetch(..., {signal: abortSignal});
```

we should also be able to cancel fetch with `zoneTask.cancel` call.
So this commit create an internal AbortSignal to handle
`zoneTask.cancel()` call and also delegate the `options.signal` from the
user code.

packages/zone.js/lib/common/events.ts

@@ -293,16 +293,6 @@ export function patchEventTarget(
       // if task is not marked as isRemoved, this call is directly
       // from Zone.prototype.cancelTask, we should remove the task
       // from tasksList of target first
-      const signal = task?.options?.signal;
-      if (typeof signal === 'object' && signal?.tasks) {
-        const abortTasks = signal.tasks;
-        for (let i = 0; i < abortTasks?.length || 0; i++) {
-          if (abortTasks[i] === task) {
-            abortTasks.splice(i, 1);
-            break;
-          }
-        }
-      }
       if (!task.isRemoved) {
         const symbolEventNames = zoneSymbolEventNames[task.eventName];
         let symbolEventName;
@@ -404,8 +394,11 @@ export function patchEventTarget(
         const passive =
             passiveSupported && !!passiveEvents && passiveEvents.indexOf(eventName) !== -1;
         const options = buildEventListenerOptions(arguments[2], passive);
-        const signal = typeof options === 'object' && options?.signal;
-        if (typeof signal === 'object' && signal?.aborted) {
+        const signal = options && typeof options === 'object' && options.signal &&
+                typeof options.signal === 'object' ?
+            options.signal :
+            undefined;
+        if (signal?.aborted) {
           // the signal is an aborted one, just return without attaching the event listener.
           return;
         }
@@ -480,7 +473,7 @@ export function patchEventTarget(
           (data as any).taskData = taskData;
         }
 
-        if (signal && typeof signal === 'object') {
+        if (signal) {
           // if addEventListener with signal options, we don't pass it to
           // native addEventListener, instead we keep the signal setting
           // and handle ourselves.
@@ -489,20 +482,12 @@ export function patchEventTarget(
         const task: any =
             zone.scheduleEventTask(source, delegate, data, customScheduleFn, customCancelFn);
 
-        if (signal && typeof signal === 'object') {
+        if (signal) {
           // after task is scheduled, we need to store the signal back to task.options
           taskData.options.signal = signal;
-          const tasks = signal.tasks || [];
-          tasks.push(task);
-          signal.tasks = tasks;
-          if (!signal[Zone.__symbol__('abortListener')]) {
-            signal[Zone.__symbol__('abortListener')] = true;
-            nativeListener.call(signal, 'abort', function() {
-              const sTasks = signal.tasks.slice();
-              sTasks.forEach((task: Task) => task.zone.cancelTask(task));
-              signal.tasks.length = 0;
-            });
-          }
+          nativeListener.call(signal, 'abort', () => {
+            task.zone.cancelTask(task);
+          }, {once: true});
         }
 
         // should clear taskData.target to avoid memory leak

packages/zone.js/lib/common/fetch.ts

@@ -26,15 +26,22 @@ Zone.__load_patch('fetch', (global: any, Zone: ZoneType, api: _ZonePrivate) => {
   const ZoneAwarePromise = global.Promise;
   const symbolThenPatched = api.symbol('thenPatched');
   const fetchTaskScheduling = api.symbol('fetchTaskScheduling');
-  const fetchTaskAborting = api.symbol('fetchTaskAborting');
-  const OriginalAbortController = global['AbortController'];
-  const supportAbort = typeof OriginalAbortController === 'function';
-  let abortNative: Function|null = OriginalAbortController?.prototype[api.symbol('abort')];
   const placeholder = function() {};
   global['fetch'] = function() {
     const args = Array.prototype.slice.call(arguments);
-    const options = args.length > 1 ? args[1] : null;
+    const options = args.length > 1 ? args[1] : {};
     const signal = options && options.signal;
+    const ac = new AbortController();
+    const fetchSignal = ac.signal;
+    options.signal = fetchSignal;
+    args[1] = options;
+    if (signal) {
+      const nativeAddEventListener =
+          signal[Zone.__symbol__('addEventListener')] || signal.addEventListener;
+      nativeAddEventListener.call(signal, 'abort', function() {
+        ac!.abort();
+      }, {once: true});
+    }
     return new Promise((res, rej) => {
       const task = Zone.current.scheduleMacroTask(
           'fetch', placeholder, {fetchArgs: args} as FetchTaskData,
@@ -72,25 +79,8 @@ Zone.__load_patch('fetch', (global: any, Zone: ZoneType, api: _ZonePrivate) => {
                 });
           },
           () => {
-            if (!supportAbort) {
-              rej('No AbortController supported, can not cancel fetch');
-              return;
-            }
-            if (signal && signal.abortController && !signal.aborted &&
-                typeof signal.abortController.abort === 'function' && abortNative) {
-              try {
-                (Zone.current as any)[fetchTaskAborting] = true;
-                abortNative.call(signal.abortController);
-              } finally {
-                (Zone.current as any)[fetchTaskAborting] = false;
-              }
-            } else {
-              rej('cancel fetch need a AbortController.signal');
-            }
+            ac.abort();
           });
-      if (signal && signal.abortController) {
-        signal.abortController.tasks = [task];
-      }
     });
   };
 });

packages/zone.js/test/browser/browser.spec.ts

@@ -1809,7 +1809,7 @@ describe('Zone', function() {
         expect(logs.length).toBe(2);
         expect(logs).toEqual(['click1', 'click2']);
 
-        button.removeEventListener('click', listener1);
+        ac.abort();
         listeners = button.eventListeners!('click');
         expect(listeners.length).toBe(1);
 
@@ -1820,11 +1820,92 @@ describe('Zone', function() {
         expect(logs.length).toBe(1);
         expect(listeners.length).toBe(1);
         expect(logs).toEqual(['click2']);
+      });
 
-        ac.abort();
+      it('should not break remove event listeners with AbortController', function() {
+        let logs: string[] = [];
+        const ac = new AbortController();
+
+        const listener1 = function() {
+          logs.push('click1');
+        };
+        button.addEventListener('click', listener1, {signal: ac.signal});
+        button.addEventListener('click', function() {
+          logs.push('click2');
+        });
+        let listeners = button.eventListeners!('click');
+        expect(listeners.length).toBe(2);
+
+        button.dispatchEvent(clickEvent);
+        expect(logs.length).toBe(2);
+        expect(logs).toEqual(['click1', 'click2']);
+
+        button.removeEventListener('click', listener1);
+        listeners = button.eventListeners!('click');
+        expect(listeners.length).toBe(1);
+
+        logs = [];
+
+        listeners = button.eventListeners!('click');
+        button.dispatchEvent(clickEvent);
+        expect(logs.length).toBe(1);
+        expect(listeners.length).toBe(1);
         expect(logs).toEqual(['click2']);
       });
 
+      it('should support remove multiple event listeners with the same AbortController',
+         function() {
+           let logs: string[] = [];
+           const ac = new AbortController();
+           const button1 = document.createElement('button');
+           const keyEvent: any = document.createEvent('KeyboardEvent');
+           keyEvent.initKeyboardEvent(
+               'keypress',  // typeArg,
+               true,        // canBubbleArg,
+               true,        // cancelableArg,
+               null,        // viewArg, Specifies UIEvent.view. This value may be null.
+               '',
+               0,
+               false,  // ctrlKeyArg,
+               false,  // altKeyArg,
+               false,  // shiftKeyArg,
+               false,  // metaKeyArg,
+           );
+           document.body.appendChild(button1);
+
+           const listener1 = function() {
+             logs.push('click1');
+           };
+           button.addEventListener('click', listener1, {signal: ac.signal});
+           button.addEventListener('click', function() {
+             logs.push('click2');
+           });
+           button1.addEventListener('keypress', () => logs.push('click3'), {signal: ac.signal});
+           button1.addEventListener('keypress', function() {
+             logs.push('click4');
+           });
+           let listeners = button.eventListeners!('click');
+           expect(listeners.length).toBe(2);
+
+           button.dispatchEvent(clickEvent);
+           expect(logs.length).toBe(2);
+           expect(logs).toEqual(['click1', 'click2']);
+           button1.dispatchEvent(keyEvent);
+           expect(logs.length).toBe(4);
+           expect(logs).toEqual(['click1', 'click2', 'click3', 'click4']);
+
+           logs = [];
+           ac.abort();
+           listeners = button.eventListeners!('click');
+           button.dispatchEvent(clickEvent);
+           expect(logs.length).toBe(1);
+           expect(listeners.length).toBe(1);
+           expect(logs).toEqual(['click2']);
+           button1.dispatchEvent(keyEvent);
+           expect(logs.length).toBe(2);
+           expect(logs).toEqual(['click2', 'click4']);
+         });
+
       it('should not add event listeners with aborted signal', function() {
         let logs: string[] = [];