polymer/lib/utils/flush.js

/**
@license
Copyright (c) 2017 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
*/
import './boot.js';
/* eslint-disable no-unused-vars */
import { Debouncer } from '../utils/debounce.js';  // used in type annotations
/* eslint-enable no-unused-vars */

let debouncerQueue = [];

/**
 * Adds a `Debouncer` to a list of globally flushable tasks.
 *
 * @param {!Debouncer} debouncer Debouncer to enqueue
 * @return {void}
 */
export const enqueueDebouncer = function(debouncer) {
  debouncerQueue.push(debouncer);
};

function flushDebouncers() {
  const didFlush = Boolean(debouncerQueue.length);
  while (debouncerQueue.length) {
    try {
      debouncerQueue.shift().flush();
    } catch(e) {
      setTimeout(() => {
        throw e;
      });
    }
  }
  return didFlush;
}

/**
 * Forces several classes of asynchronously queued tasks to flush:
 * - Debouncers added via `enqueueDebouncer`
 * - ShadyDOM distribution
 *
 * @return {void}
 */
export const flush = function() {
  let shadyDOM, debouncers;
  do {
    shadyDOM = window.ShadyDOM && ShadyDOM.flush();
    if (window.ShadyCSS && window.ShadyCSS.ScopingShim) {
      window.ShadyCSS.ScopingShim.flush();
    }
    debouncers = flushDebouncers();
  } while (shadyDOM || debouncers);
};