import { type MarkedCallback } from './shared';
type HelpByQuery = MarkedCallback & {
    /**
     * Exact title of an existing help page, with optional anchor hash.
     */
    page?: string;
    path?: never;
    syntax?: 'query';
};
type HelpByPath = MarkedCallback & {
    /**
     * Help page path. Marked allows a colon in place of a hash anchor.
     */
    path: string;
    syntax: 'path';
    page?: never;
};
/**
 * Help payload definition.
 */
export type Help = HelpByQuery | HelpByPath;
/**
 * Open the Marked internal help system.
 *
 * @param payload Help payload.
 * @returns Marked help URL.
 * @example
 * help({ page: 'Document_Statistics' })
 * // => 'x-marked://help?page=Document_Statistics'
 * @example
 * help({ path: 'Keyword_Highlighting:editingkeywords', syntax: 'path' })
 * // => 'x-marked://help/Keyword_Highlighting:editingkeywords'
 * @link https://marked2app.com/help/URL_Handler.html#help
 */
export declare function help(payload?: Help): string;
export {};