/** @license Copyright (c) 2018 The Polymer Project Authors. All rights reserved. This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt Code distributed by Google as part of the polymer project is also subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt */ /** Utility method that calls a callback whenever a media-query matches in response to the viewport size changing. The callback should take a boolean parameter (with `true` meaning the media query is matched). Example: import { installMediaQueryWatcher } from 'pwa-helpers/media-query.js'; installMediaQueryWatcher(`(min-width: 600px)`, (matches) => { console.log(matches ? 'wide screen' : 'narrow sreen'); }); */ export declare const installMediaQueryWatcher: (mediaQuery: string, layoutChangedCallback: (mediaQueryMatches: boolean) => void) => void;