fix to onFinish callback flow

CHANGELOG.md

@@ -2,6 +2,12 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+## [Not released][Not released]
+
+### Fixed
+- `to` don't throw error if no `onFinish` callback
+
+
 ## [0.9.0][2015-02-27]
 
 ### Fixed

src/Tween.js

@@ -290,7 +290,7 @@
         params.node = this;
         params.onFinish = function() {
             tween.destroy();
-            onFinish();
+            onFinish && onFinish();
         };
         var tween = new Konva.Tween(params);
         tween.play();

test/unit/Tween-test.js

@@ -170,7 +170,7 @@ suite('Tween', function() {
         tween.play();
     });
 
-    test('transitionTo method', function(done) {
+    test('to method', function(done) {
         var stage = addStage();
 
         var layer = new Konva.Layer();
@@ -197,5 +197,17 @@ suite('Tween', function() {
         });
     });
 
+    test('to method simple usage', function(done) {
+        var stage = addStage();
+
+        stage.to({
+            x : 10,
+            duration : 0.001
+        });
+        setTimeout(function() {
+            done();
+        }, 50);
+    });
+
 
 });