It was working before the last update. getElement method returns null.
# DomHelper Class
outerWidth(element, margin = false) {
let el = this.getElement(element);
let width = el.offsetWidth;
if (margin) {
let style = getComputedStyle(el);
width += (parseInt(style.getPropertyValue('margin-left')) || 0) + (parseInt(style.getPropertyValue('margin-right')) || 0);
}
return width;
}