dom.js

/**
 * @license
 * Copyright 2017 Google Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

/**
 * @param {string} query
 * @param {!Document|!Element=} root
 * @return {!Array<!Element>}
 */
export function getAll(query, root = document) {
  return [].slice.call(root.querySelectorAll(query));
}

/**
 * @param {!Window|!Document|!Element} root
 * @return {!Document|undefined}
 */
export function getDocument(root) {
  return root.ownerDocument || root.document || (root.documentElement ? root : undefined);
}

/**
 * @param {!Window|!Document|!Element} root
 * @return {!Window|undefined}
 */
export function getWindow(root) {
  const doc = getDocument(root);
  return doc.defaultView || doc.parentWindow || (root.document ? root : undefined);
}