Merge pull request #251 from brianmaissy/waterfall

calling waterfall with a non-array first argument results in an error

2 files changed, 11 insertions, 0 deletions

diff --git a/lib/async.js b/lib/async.js
index ad3982a..5747dbd 100755
--- a/lib/async.js
+++ b/lib/async.js
@@ -467,6 +467,10 @@
 
     async.waterfall = function (tasks, callback) {
         callback = callback || function () {};
+        if (tasks.constructor !== Array) {
+          var err = new Error('First argument to waterfall must be an array of functions');
+          return callback(err);
+        }
         if (!tasks.length) {
             return callback();
         }
diff --git a/test/test-async.js b/test/test-async.js
index 5bd72bf..1f0564f 100755
--- a/test/test-async.js
+++ b/test/test-async.js
@@ -420,6 +420,13 @@ exports['waterfall empty array'] = function(test){
     });
 };
 
+exports['waterfall non-array'] = function(test){
+    async.waterfall({}, function(err){
+        test.equals(err.message, 'First argument to waterfall must be an array of functions');
+        test.done();
+    });
+};
+
 exports['waterfall no callback'] = function(test){
     async.waterfall([
         function(callback){callback();},