/**
 * Returns the highlighted index when the menu is opened.
 * Takes into account the initialHighlightedIndex, defaultHighlightedIndex,
 * selectedItem, and the open direction offset.
 *
 * @param items The list of items.
 * @param initialHighlightedIndex The initial highlighted index prop.
 * @param defaultHighlightedIndex The default highlighted index prop.
 * @param isItemDisabled Callback to determine if an item is disabled.
 * @param itemToKey Callback to get a unique key from an item.
 * @param selectedItem The currently selected item.
 * @param highlightedIndex The current highlighted index from state.
 * @param offset The direction of navigation: positive opens downward, negative opens upward.
 * @returns The new highlighted index.
 */
export declare function getHighlightedIndexOnOpen<Item>(items: Item[], initialHighlightedIndex: number | undefined, defaultHighlightedIndex: number | undefined, isItemDisabled: (item: Item, index: number) => boolean, itemToKey: (item: Item | null) => unknown, selectedItem: Item | null, highlightedIndex: number, offset: number): number;