export declare function getClosestTreeItem(element: Element): null | HTMLLIElement;
export declare function getToggleButtonOfTreeItem(treeItem: null | HTMLLIElement): null | HTMLElement;
export declare function isElementDisabled(element: HTMLElement): boolean;
export declare function findTreeItemByIndex(treeView: HTMLUListElement, targetTreeItemIndex: number, delta: number): HTMLLIElement | null;
export declare function findTreeItemContentById(treeView: HTMLUListElement, treeItemId: string): null | HTMLLIElement;
export declare function isTreeItemToggle(element: Element): boolean;