From 709b8611af3b64bc6ab6e012c355ef3f1aa1fae6 Mon Sep 17 00:00:00 2001
From: dacoozheng <23788425@qq.com>
Date: Sun, 3 Jan 2016 16:23:02 +0800
Subject: [PATCH 1/3] prevent return "undefined" immediately when key is
 "constructor" for memoize method.

---
 lib/async.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/async.js b/lib/async.js
index 839a66a0c..38da842bb 100644
--- a/lib/async.js
+++ b/lib/async.js
@@ -1089,12 +1089,12 @@
         var memoized = _restParam(function memoized(args) {
             var callback = args.pop();
             var key = hasher.apply(null, args);
-            if (key in memo) {
+            if (memo.hasOwnProperty(key)) {
                 async.setImmediate(function () {
                     callback.apply(null, memo[key]);
                 });
             }
-            else if (key in queues) {
+            else if (queues.hasOwnProperty(key)) {
                 queues[key].push(callback);
             }
             else {

From 4a6ac52b15f7431e01f6f92a9b03dc2fe36e3b8a Mon Sep 17 00:00:00 2001
From: dacoozheng <23788425@qq.com>
Date: Sun, 3 Jan 2016 19:18:43 +0800
Subject: [PATCH 2/3] Test case for #998.

---
 test/test-async.js | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/test/test-async.js b/test/test-async.js
index 05c022827..19c30c137 100755
--- a/test/test-async.js
+++ b/test/test-async.js
@@ -4309,6 +4309,32 @@ exports['memoize'] = {
         test.equal(val, "bar");
         test.done();
     });
+},
+
+    'avoid constructor key return undefined': function (test) {
+    test.expect(1);
+    var fn = async.memoize(function(name, callback) {
+        async.setImmediate(function(){
+            callback(null, name);
+        });
+    });
+    fn('constructor', function(error, results) {
+        test.equal(results, 'constructor');
+        test.done();
+    });
+},
+
+    'avoid __proto__ key return undefined': function (test) {
+    test.expect(1);
+    var fn = async.memoize(function(name, callback) {
+        async.setImmediate(function(){
+            callback(null, name);
+        });
+    });
+    fn('__proto__', function(error, results) {
+        test.equal(results, '__proto__');
+        test.done();
+    });
 }
 
 };

From 16d61f49c88b4c3167a0c592f08216cbd23ade8d Mon Sep 17 00:00:00 2001
From: dacoozheng <23788425@qq.com>
Date: Sun, 3 Jan 2016 21:22:14 +0800
Subject: [PATCH 3/3] Allow "hasOwnProperty" as key for memoize method.

---
 lib/async.js       |  5 +++--
 test/test-async.js | 21 +++++++++++++++++----
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/lib/async.js b/lib/async.js
index 38da842bb..8cdb9ca57 100644
--- a/lib/async.js
+++ b/lib/async.js
@@ -1085,16 +1085,17 @@
     async.memoize = function (fn, hasher) {
         var memo = {};
         var queues = {};
+        var has = Object.prototype.hasOwnProperty;
         hasher = hasher || identity;
         var memoized = _restParam(function memoized(args) {
             var callback = args.pop();
             var key = hasher.apply(null, args);
-            if (memo.hasOwnProperty(key)) {
+            if (has.call(memo, key)) {   
                 async.setImmediate(function () {
                     callback.apply(null, memo[key]);
                 });
             }
-            else if (queues.hasOwnProperty(key)) {
+            else if (has.call(queues, key)) {
                 queues[key].push(callback);
             }
             else {
diff --git a/test/test-async.js b/test/test-async.js
index 19c30c137..e6fe8effd 100755
--- a/test/test-async.js
+++ b/test/test-async.js
@@ -4314,9 +4314,9 @@ exports['memoize'] = {
     'avoid constructor key return undefined': function (test) {
     test.expect(1);
     var fn = async.memoize(function(name, callback) {
-        async.setImmediate(function(){
+        setTimeout(function(){
             callback(null, name);
-        });
+        }, 100);
     });
     fn('constructor', function(error, results) {
         test.equal(results, 'constructor');
@@ -4327,14 +4327,27 @@ exports['memoize'] = {
     'avoid __proto__ key return undefined': function (test) {
     test.expect(1);
     var fn = async.memoize(function(name, callback) {
-        async.setImmediate(function(){
+        setTimeout(function(){
             callback(null, name);
-        });
+        }, 100);
     });
     fn('__proto__', function(error, results) {
         test.equal(results, '__proto__');
         test.done();
     });
+},
+
+    'allow hasOwnProperty as key': function (test) {
+    test.expect(1);
+    var fn = async.memoize(function(name, callback) {
+        setTimeout(function(){
+            callback(null, name);
+        }, 100);
+    });
+    fn('hasOwnProperty', function(error, results) {
+        test.equal(results, 'hasOwnProperty');
+        test.done();
+    });
 }
 
 };