The Slide Toggle in Material Design does not have a stopPropagation event, because the "MdSlideToggle.prototype._onChangeEvent" already calls stopPropagation. What should I be using, instead?

<md-slide-toggle (change)="changeToggle($event, activityType.isActive)" checked="activityType.isActive" value="activityType.activityTypeId" mdTooltip="{{!!activityType.isActive ? 'Active' : 'Inactive'}}" mdTooltipPosition="left"></md-slide-toggle>


public changeToggle(event: MdSlideToggleChange, originalValue){
    if (this.hasChange && event.checked !== originalValue){
        event.stopPropagation();
        //Results in error: [ts] Property 'stopPropagation' does not exist on type 'MdSlideToggleChange'.
    } else {
        this.hasChange = !this.hasChange;
    }
}

I can use a regular event, but that gets an exception saying "event.stopPropagation is not a function".

For the moment, I'm changing that line to:

event.source.checked = !event.checked;

The same is true of event.preventDefault. I need to require the user to save the change, before changing another value on the page, because "business requirements".

Is just changing the value of "checked" back to what it was, the right thing to do? Is there a better way to do this?