1 files changed, 10 insertions, 3 deletions
diff --git a/lib/async.js b/lib/async.js
index 58b11d9..abc1f7b 100644
--- a/lib/async.js
+++ b/lib/async.js
@@ -335,7 +335,7 @@
     }
 
     function _asyncMap(eachfn, arr, iterator, callback) {
-        callback = callback || noop;
+        callback = _once(callback || noop);
         var results = [];
         eachfn(arr, function (value, index, callback) {
             iterator(value, function (err, v) {
@@ -822,7 +822,7 @@
             _arrayEach(data, function(task) {
                 var item = {
                     data: task,
-                    callback: typeof callback === 'function' ? callback : noop
+                    callback: callback || noop
                 };
 
                 if (pos) {
@@ -1077,7 +1077,14 @@
         return function () {
             var that = this;
             var args = _baseSlice(arguments);
-            var callback = args.pop();
+
+            var callback = args.slice(-1)[0];
+            if (typeof callback == 'function') {
+                args.pop();
+            } else {
+                callback = noop;
+            }
+
             async.reduce(fns, args, function (newargs, fn, cb) {
                 fn.apply(that, newargs.concat([function () {
                     var err = arguments[0];