Spinner: Drop dependency on jQuery Mousewheel

1. Listen to the native `wheel` event without depending on any wrapper plugins.
2. Keep listening to the `mousewheel` event for compatibility with projects
   using the jQuery Mousewheel plugin but route it to the `wheel` handler.

Closes gh-2338

1 files changed, 17 insertions, 2 deletions

diff --git a/ui/widgets/spinner.js b/ui/widgets/spinner.js
index d999d85d7..4fb41d7bb 100644
--- a/ui/widgets/spinner.js
+++ b/ui/widgets/spinner.js
@@ -136,9 +136,10 @@ $.widget( "ui.spinner", {
 				this._trigger( "change", event );
 			}
 		},
-		mousewheel: function( event, delta ) {
+		wheel: function( event ) {
 			var activeElement = this.document[ 0 ].activeElement;
 			var isActive = this.element[ 0 ] === activeElement;
+			var delta = event.deltaY || event.originalEvent && event.originalEvent.deltaY;
 
 			if ( !isActive || !delta ) {
 				return;
@@ -148,7 +149,7 @@ $.widget( "ui.spinner", {
 				return false;
 			}
 
-			this._spin( ( delta > 0 ? 1 : -1 ) * this.options.step, event );
+			this._spin( ( delta > 0 ? -1 : 1 ) * this.options.step, event );
 			clearTimeout( this.mousewheelTimer );
 			this.mousewheelTimer = this._delay( function() {
 				if ( this.spinning ) {
@@ -157,6 +158,20 @@ $.widget( "ui.spinner", {
 			}, 100 );
 			event.preventDefault();
 		},
+
+		// DEPRECATED
+		// Kept for backwards compatibility. Please use the modern `wheel`
+		// event. The `delta` parameter is provided by the jQuery Mousewheel
+		// plugin if one is loaded.
+		mousewheel: function( event, delta ) {
+			var wheelEvent = $.Event( event );
+			wheelEvent.type = "wheel";
+			if ( delta ) {
+				wheelEvent.deltaY = -delta;
+			}
+			return this._events.wheel.call( this, wheelEvent );
+		},
+
 		"mousedown .ui-spinner-button": function( event ) {
 			var previous;