Added wheel service (pending tests)

Author: joelmukuthu

src/directives/snapscroll.js

@@ -86,70 +86,51 @@
     });
   };
 
-  var initWheelEvents = function (scope, element) {
-    var onWheel,
-        bindWheel,
-        unbindWheel;
-
-    onWheel = function (e) {
-      var bubbleUp,
-          delta;
-
-      if (e.originalEvent) {
-        e = e.originalEvent;
-      }
-
-      e.preventDefault();
-
-      delta = Math.max(-1, Math.min(1, (e.wheelDelta || -(e.deltaY || e.detail))));
-
-      if (isNaN(delta) || delta === 0) {
-        return;
+  var initWheelEvents = function (wheel, scope, element) {
+    function maybePreventBubbling(e, bubbleUp) {
+      if (!bubbleUp) {
+        e.stopPropagation();
       }
+    }
 
-      if (delta < 0) {
-        if (scope.snapDirection !== 1) {
-          if (scope.snapIndex + 1 > scope.scopeIndexMax()) {
+    wheel.bind(element, {
+      up: function (e) {
+        var bubbleUp;
+        if (scope.snapDirection !== -1) {
+          if (scope.snapIndex - 1 < scope.snapIndexMin()) {
             bubbleUp = true;
           } else {
             bubbleUp = false;
             scope.$apply(function () {
-              scope.snapIndex += 1;
+              scope.snapIndex -= 1;
             });
           }
         }
-      } else {
-        if (scope.snapDirection !== -1) {
-          if (scope.snapIndex - 1 < scope.snapIndexMin()) {
+        maybePreventBubbling(e, bubbleUp);
+      },
+      down: function (e) {
+        var bubbleUp;
+        if (scope.snapDirection !== 1) {
+          if (scope.snapIndex + 1 > scope.scopeIndexMax()) {
             bubbleUp = true;
           } else {
             bubbleUp = false;
             scope.$apply(function () {
-              scope.snapIndex -= 1;
+              scope.snapIndex += 1;
             });
           }
         }
+        maybePreventBubbling(e, bubbleUp);
       }
+    });
 
-      if (!bubbleUp) {
-        e.stopPropagation();
-      }
-    };
-
-    bindWheel = function () {
-      element.on('wheel mousewheel onmousewheel', onWheel);
-    };
-
-    unbindWheel = function () {
-      element.off('wheel mousewheel onmousewheel', onWheel);
-    };
-
-    bindWheel();
-    scope.$on('$destroy', unbindWheel);
+    scope.$on('$destroy', function () {
+      wheel.unbind(element);
+    });
   };
 
-  var snapscrollAsAnAttribute = ['$timeout', 'scroll', 'defaultSnapscrollScrollDelay', 'defaultSnapscrollSnapDuration', 'defaultSnapscrollBindScrollTimeout',
-    function ($timeout, scroll, defaultSnapscrollScrollDelay, defaultSnapscrollSnapDuration, defaultSnapscrollBindScrollTimeout) {
+  var snapscrollAsAnAttribute = ['$timeout', 'scroll', 'wheel', 'defaultSnapscrollScrollDelay', 'defaultSnapscrollSnapDuration', 'defaultSnapscrollBindScrollTimeout',
+    function ($timeout, scroll, wheel, defaultSnapscrollScrollDelay, defaultSnapscrollSnapDuration, defaultSnapscrollBindScrollTimeout) {
       return {
         restrict: 'A',
         scope: scopeObject,
@@ -290,7 +271,7 @@
               scope.$on('$destroy', unbindScroll);
             }
 
-            initWheelEvents(scope, element);
+            initWheelEvents(wheel, scope, element);
           };
 
           init();

src/services/wheel.js

@@ -0,0 +1,46 @@
+(function () {
+  'use strict';
+
+  var snapscroll = angular.module('snapscroll');
+
+  snapscroll.factory('wheel', [function () {
+    function onWheel(e, up, down) {
+      var delta;
+
+      if (e.originalEvent) {
+        e = e.originalEvent;
+      }
+      e.preventDefault();
+
+      delta = Math.max(-1, Math.min(1, (e.wheelDelta || -(e.deltaY || e.detail))));
+      if (isNaN(delta) || delta === 0) {
+        return;
+      }
+
+      if (delta < 0) {
+        down(e);
+      } else {
+        up(e);
+      }
+    }
+
+    return {
+      bind: function (element, callbacks) {
+        function bindWheel(e) {
+          onWheel(e, callbacks.up, callbacks.down);
+        }
+        element.data('snapscroll-bindWheel', bindWheel);
+        element.on('wheel mousewheel onmousewheel', bindWheel);
+      },
+
+      unbind: function (element) {
+        var bindWheel = element.data('snapscroll-bindWheel');
+        if (bindWheel) {
+          element.data('snapscroll-bindWheel', null);
+          element.off('wheel mousewheel onmousewheel', bindWheel);
+        }
+      }
+    };
+  }]);
+
+})();