import { type Writable, type Readable } from 'svelte/store';
import type { Page } from '@sveltejs/kit';
import type { FlashOptions } from './options.js';
export declare function initFlash(page: Readable<Page>, options?: Partial<FlashOptions>): Writable<App.PageData['flash']>;
/**
 * Retrieves the flash message store for display or modification.
 * @param page Page store, imported from `$app/state`.
 * @param {FlashOptions} options for the flash message. Can only be set once, usually at the highest level component where getFlash is called for the first time.
 * @returns The flash message store.
 */
export declare function getFlash(page: Readable<Page> | Page, options?: Partial<FlashOptions>): Writable<App.PageData['flash']>;
/**
 * Update the flash message manually, usually after a fetch request.
 * @param page Page store, imported from `$app/state`.
 * @param {Promise<void>} update A callback which is executed *before* the message is updated, to delay the message until navigation events are completed, for example when using `goto`.
 * @returns {Promise<boolean>} `true` if a flash message existed, `false` if not.
 */
export declare function updateFlash(page: Readable<Page> | Page, update?: () => Promise<void>): Promise<boolean>;