export declare class AbsDomHelperService {
    constructor();
    deepEquals(x: any, y: any): boolean;
    isHidden(node: any): any;
    isTabable(node: any): boolean;
    private isValidChild(child);
    private hasValidParent(obj);
    private traverse(obj, fromTop);
    previousElement(el: any, isFocusable: any): any;
    lastTabableElement(el: any): any;
    firstTabableElement(el: any): any;
    isInDOM(obj: any): boolean;
}