import type { Option, OptionStyle } from '../types';
/**
 * Get the label key from an option object or the option itself if it's a string or number
 * @param opt Option
 * @returns Label
 */
export declare const get_label: (opt: Option) => any;
/**
 * This function is used extract CSS strings from a {selected, option} style object to be used in the style attribute of the option.
 * If the style is a string, it will be returned as is
 * @param option Option
 * @param key
 * @returns CSS string
 */
export declare function get_style(option: {
    style?: OptionStyle;
    [key: string]: unknown;
} | string | number, key?: `selected` | `option` | null): any;
/**
 * Highlights text nodes that matching the string query
 * @param element Parent element
 * @param query Search query
 * @param noMatchingOptionsMsg Text for empty node
 */
export declare function highlight_matching_nodes(element: HTMLElement, query?: string, noMatchingOptionsMsg?: string): void;