fix(ionicScrollDelegate): do not error if no scrollTop/Left values

Closes #659

Author: ajoslin

js/ext/angular/src/service/delegates/ionicScrollDelegate.js

@@ -73,31 +73,16 @@ angular.module('ionic.ui.service.scrollDelegate', [])
         });
       }
 
-      $element.bind('scroll', function(e) {
-
-        var elem;
-
+      $element.on('scroll', function(e) {
         if ( !$scope.onScroll ) {
           return;
         }
-
-        elem = {
-          scrollTop: 0,
-          scrollLeft: 0
-        };
-
-        if ( e.detail && e.detail.scrollTop && e.detail.scrollLeft ) {
-          elem = e.detail;
-        } else {
-          if ( e.originalEvent && e.originalEvent.detail && e.originalEvent.detail.scrollTop && e.originalEvent.detail.scrollLeft ) {
-            elem = e.originalEvent.detail;
-          }
-        }
+        var detail = (e.originalEvent || e).detail || {};
 
         $scope.onScroll && $scope.onScroll({
           event: e,
-          scrollTop: elem.scrollTop,
-          scrollLeft: elem.scrollLeft
+          scrollTop: detail.scrollTop || 0,
+          scrollLeft: detail.scrollLeft || 0
         });
 
       });

js/ext/angular/test/service/delegates/ionicScrollDelegate.unit.js

@@ -1,4 +1,4 @@
-describe('Ionic ScrollDelegate Service', function() {
+ddescribe('Ionic ScrollDelegate Service', function() {
   var del, rootScope, compile, timeout, document;
 
   beforeEach(module('ionic'));
@@ -31,6 +31,26 @@ describe('Ionic ScrollDelegate Service', function() {
     expect(sv.resize).toHaveBeenCalled();
   });
 
+  it('scroll event', function() {
+    var scope = rootScope.$new();
+    var el = compile('<ion-content></ion-content>')(scope);
+    scope = el.isolateScope();
+    scope.$apply();
+    var top, left;
+    scope.onScroll = jasmine.createSpy('scroll').andCallFake(function(data) {
+      top = data.scrollTop;
+      left = data.scrollLeft;
+    });
+    ionic.trigger('scroll', {target: el[0]});
+    expect(scope.onScroll).toHaveBeenCalled();
+    expect(top).toBe(0);
+    expect(left).toBe(0);
+
+    ionic.trigger('scroll', {target: el[0], scrollTop: 3, scrollLeft: 4});
+    expect(top).toBe(3);
+    expect(left).toBe(4);
+  });
+
   testWithAnimate(true);
   testWithAnimate(false);
   function testWithAnimate(animate) {