From 1822cbcd46653ef1507a5a5be831431f2560b289 Mon Sep 17 00:00:00 2001
From: JiaLiPassion <JiaLi.Passion@gmail.com>
Date: Wed, 1 Jul 2020 07:15:22 +0900
Subject: [PATCH] fix(zone.js): patch nodejs EventEmtter.prototype.off (#37863)

Close #35473

zone.js nodejs patch should also patch `EventEmitter.prototype.off` as `removeListener`.
So `off` can correctly remove the listeners added by `EventEmitter.prototype.addListener`

PR Close #37863
---
 packages/zone.js/lib/node/events.ts       |  2 ++
 packages/zone.js/test/node/events.spec.ts | 12 ++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/packages/zone.js/lib/node/events.ts b/packages/zone.js/lib/node/events.ts
index 2366332c5c..f09f8a4216 100644
--- a/packages/zone.js/lib/node/events.ts
+++ b/packages/zone.js/lib/node/events.ts
@@ -16,6 +16,7 @@ Zone.__load_patch('EventEmitter', (global: any) => {
   const EE_REMOVE_ALL_LISTENER = 'removeAllListeners';
   const EE_LISTENERS = 'listeners';
   const EE_ON = 'on';
+  const EE_OFF = 'off';
 
   const compareTaskCallbackVsDelegate = function(task: any, delegate: any) {
     // same callback, same capture, same event name, just return
@@ -47,6 +48,7 @@ Zone.__load_patch('EventEmitter', (global: any) => {
     });
     if (result && result[0]) {
       obj[EE_ON] = obj[EE_ADD_LISTENER];
+      obj[EE_OFF] = obj[EE_REMOVE_LISTENER];
     }
   }
 
diff --git a/packages/zone.js/test/node/events.spec.ts b/packages/zone.js/test/node/events.spec.ts
index f50b0eb02f..9cab424169 100644
--- a/packages/zone.js/test/node/events.spec.ts
+++ b/packages/zone.js/test/node/events.spec.ts
@@ -66,6 +66,18 @@ describe('nodejs EventEmitter', () => {
       emitter.emit('test2', 'test value');
     });
   });
+  it('should remove listeners by calling off properly', () => {
+    zoneA.run(() => {
+      emitter.on('test', shouldNotRun);
+      emitter.on('test2', shouldNotRun);
+      emitter.off('test', shouldNotRun);
+    });
+    zoneB.run(() => {
+      emitter.off('test2', shouldNotRun);
+      emitter.emit('test', 'test value');
+      emitter.emit('test2', 'test value');
+    });
+  });
   it('remove listener should return event emitter', () => {
     zoneA.run(() => {
       emitter.on('test', shouldNotRun);