Rx-js = mouseWheel handling

mouseWheel.js

var canvasMouseOver = Rx.Observable.fromEvent(myCanvas, "mousedown");
var canvasMouseWheel = Rx.Observable.fromEvent(myCanvas, "mousewheel");
            
canvasMouseWheel.skipUntil(cavasMouseOver)
                .subscribe(function (val) {

                  if (val.originalEvent.wheelDelta < 0) {
                        mainViewVM.incrementFrame();
                    }
                    else {
                        mainViewVM.decrementFrame();
                    }
            });