fix(event): fix #1021, removeListener/removeAllListeners should return eventEmitter (#1022)

Author: JiaLiPassion

lib/common/events.ts

@@ -497,6 +497,9 @@ export function patchEventTarget(
               target[symbolEventName] = null;
             }
             existingTask.zone.cancelTask(existingTask);
+            if (returnTarget) {
+              return target;
+            }
             return;
           }
         }
@@ -571,6 +574,10 @@ export function patchEventTarget(
           }
         }
       }
+
+      if (returnTarget) {
+        return this;
+      }
     };
 
     // for native toString patch

test/node/events.spec.ts

@@ -66,6 +66,13 @@ describe('nodejs EventEmitter', () => {
       emitter.emit('test2', 'test value');
     });
   });
+  it('remove listener should return event emitter', () => {
+    zoneA.run(() => {
+      emitter.on('test', shouldNotRun);
+      expect(emitter.removeListener('test', shouldNotRun)).toEqual(emitter);
+      emitter.emit('test', 'test value');
+    });
+  });
   it('should return all listeners for an event', () => {
     zoneA.run(() => {
       emitter.on('test', expectZoneA);
@@ -106,6 +113,14 @@ describe('nodejs EventEmitter', () => {
       expect(emitter.listeners('test').length).toEqual(0);
     });
   });
+  it('remove All listeners should return event emitter', () => {
+    zoneA.run(() => {
+      emitter.on('test', expectZoneA);
+      emitter.on('test', expectZoneA);
+      expect(emitter.removeAllListeners('test')).toEqual(emitter);
+      expect(emitter.listeners('test').length).toEqual(0);
+    });
+  });
   it('should remove All listeners properly even without a type parameter', () => {
     zoneA.run(() => {
       emitter.on('test', shouldNotRun);