getting MapZoomEndedEvent values in Custom View

Hi, I am looking for help in finding out whether something wrong in my code or the result is expected.

I subscribe the “MapZoomEndedEvent” so when users zoom in/out the HTML 5 viewer map I will get Extent, zoomFactor, anchor, and level from the event.  According to GVH Commands & Events (https://docs.geocortex.com/essentials/gvh/latest/commands-help/index.html#/events/Map/MapZoomEndedEvent) four values should be in the event.  However, from the Chrome Developer debugger, the “evt” contains only one value - the extent.

Chrome Debugger shows this:

 

this.app.eventRegistry.event("MapZoomEndedEvent").subscribe(this,function (evt) { evt: Object { xmin: -13570694.452932538, ymin: 4488121.809822625, xmax: -13570014.28281356}

This is the code segment I have in the view model:

interface MyMapZoomEndedEvent {

 

    extent: Extent;

 

    zoomFactor: number;

 

    anchor: Point;

 

    level: number;

 

}

export class AddDraggableLabelsViewModel extends ViewModelBase {

 

app: ViewerApplication;

    initialize() {

 

        this.app.eventRegistry.event("MapZoomEndedEvent").subscribe(this, (evt: MyMapZoomEndedEvent) => {

 

            this.app.command("Alert").execute("zoomed factor = {0}, zoomed level={1}".format(evt.zoomFactor, evt.level));

 

        });

 

        };

 

}

Thank you in advance.