import type IgcTreeComponent from './tree.js';
import type { IgcTreeSelectionService } from './tree.selection.js';
import type IgcTreeItemComponent from './tree-item.js';
export declare const NAVIGATION_KEYS: Set<string>;
export declare class IgcTreeNavigationService {
    private tree;
    private selectionService;
    private _focusedItem;
    private _lastFocusedItem;
    private _activeItem;
    private _visibleChildren;
    private _invisibleChildren;
    private _disabledChildren;
    constructor(tree: IgcTreeComponent, selectionService: IgcTreeSelectionService);
    updateVisChild(): void;
    get focusedItem(): IgcTreeItemComponent | null;
    focusItem(value: IgcTreeItemComponent | null, shouldFocus?: boolean): void;
    get activeItem(): IgcTreeItemComponent | null;
    setActiveItem(value: IgcTreeItemComponent | null, shouldEmit?: boolean): void;
    get visibleChildren(): IgcTreeItemComponent[];
    update_disabled_cache(item: IgcTreeItemComponent): void;
    delete_item(item: IgcTreeItemComponent): void;
    update_visible_cache(item: IgcTreeItemComponent, expanded: boolean, shouldUpdateNestedChildren?: boolean, shouldUpdate?: boolean): void;
    /**
     * Sets the item as focused (and active)
     *
     * @param item target item
     * @param isActive if true, sets the item as active
     */
    setFocusedAndActiveItem(item: IgcTreeItemComponent, isActive?: boolean, shouldFocus?: boolean): void;
    /** Handler for keydown events. Used in tree.component.ts */
    handleKeydown(event: KeyboardEvent): void;
    private handleNavigation;
    private handleArrowLeft;
    private handleArrowRight;
    private handleUpDownArrow;
    private handleAsterisk;
    private handleSpace;
    /** Gets the next visible item in the given direction - 1 -> next, -1 -> previous */
    private getVisibleItem;
}