Bring object to front dynamically doesn't work anymore

Hello, I followed other threads to bring objects to the front dynamically through all the following scripts in HTML5.

// ES5 setChildIndex

this.bringToFront = function(e) {

    e.currentTarget.parent.setChildIndex(e.currentTarget, e.currentTarget.parent.numChildren - 1);

}

// ES6 setChildIndex

this.bringToFront = (e) => {

    e.currentTarget.parent.setChildIndex(e.currentTarget, e.currentTarget.parent.numChildren - 1);

}

// ES5 addChild

this.bringToFront = function(e) {

    e.currentTarget.parent.addChild(e.currentTarget);

}

// ES6 addChild

this.bringToFront = (e) => {

    e.currentTarget.parent.addChild(e.currentTarget);

}

None of these methods work any more. Maybe there was an update. Could anyone tell an alternate way?