formipay/node_modules/@wordpress/priority-queue/build/index.js

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.createQueue = void 0;
var _requestIdleCallback = _interopRequireDefault(require("./request-idle-callback"));
/**
 * Internal dependencies
 */

/**
 * Enqueued callback to invoke once idle time permits.
 *
 * @typedef {()=>void} WPPriorityQueueCallback
 */

/**
 * An object used to associate callbacks in a particular context grouping.
 *
 * @typedef {{}} WPPriorityQueueContext
 */

/**
 * Function to add callback to priority queue.
 *
 * @typedef {(element:WPPriorityQueueContext,item:WPPriorityQueueCallback)=>void} WPPriorityQueueAdd
 */

/**
 * Function to flush callbacks from priority queue.
 *
 * @typedef {(element:WPPriorityQueueContext)=>boolean} WPPriorityQueueFlush
 */

/**
 * Reset the queue.
 *
 * @typedef {()=>void} WPPriorityQueueReset
 */

/**
 * Priority queue instance.
 *
 * @typedef {Object} WPPriorityQueue
 *
 * @property {WPPriorityQueueAdd}   add    Add callback to queue for context.
 * @property {WPPriorityQueueFlush} flush  Flush queue for context.
 * @property {WPPriorityQueueFlush} cancel Clear queue for context.
 * @property {WPPriorityQueueReset} reset  Reset queue.
 */

/**
 * Creates a context-aware queue that only executes
 * the last task of a given context.
 *
 * @example
 *```js
 * import { createQueue } from '@wordpress/priority-queue';
 *
 * const queue = createQueue();
 *
 * // Context objects.
 * const ctx1 = {};
 * const ctx2 = {};
 *
 * // For a given context in the queue, only the last callback is executed.
 * queue.add( ctx1, () => console.log( 'This will be printed first' ) );
 * queue.add( ctx2, () => console.log( 'This won\'t be printed' ) );
 * queue.add( ctx2, () => console.log( 'This will be printed second' ) );
 *```
 *
 * @return {WPPriorityQueue} Queue object with `add`, `flush` and `reset` methods.
 */
const createQueue = () => {
  /** @type {Map<WPPriorityQueueContext, WPPriorityQueueCallback>} */
  const waitingList = new Map();
  let isRunning = false;

  /**
   * Callback to process as much queue as time permits.
   *
   * Map Iteration follows the original insertion order. This means that here
   * we can iterate the queue and know that the first contexts which were
   * added will be run first. On the other hand, if anyone adds a new callback
   * for an existing context it will supplant the previously-set callback for
   * that context because we reassigned that map key's value.
   *
   * In the case that a callback adds a new callback to its own context then
   * the callback it adds will appear at the end of the iteration and will be
   * run only after all other existing contexts have finished executing.
   *
   * @param {IdleDeadline|number} deadline Idle callback deadline object, or
   *                                       animation frame timestamp.
   */
  const runWaitingList = deadline => {
    for (const [nextElement, callback] of waitingList) {
      waitingList.delete(nextElement);
      callback();
      if ('number' === typeof deadline || deadline.timeRemaining() <= 0) {
        break;
      }
    }
    if (waitingList.size === 0) {
      isRunning = false;
      return;
    }
    (0, _requestIdleCallback.default)(runWaitingList);
  };

  /**
   * Add a callback to the queue for a given context.
   *
   * If errors with undefined callbacks are encountered double check that
   * all of your useSelect calls have the right dependencies set correctly
   * in their second parameter. Missing dependencies can cause unexpected
   * loops and race conditions in the queue.
   *
   * @type {WPPriorityQueueAdd}
   *
   * @param {WPPriorityQueueContext}  element Context object.
   * @param {WPPriorityQueueCallback} item    Callback function.
   */
  const add = (element, item) => {
    waitingList.set(element, item);
    if (!isRunning) {
      isRunning = true;
      (0, _requestIdleCallback.default)(runWaitingList);
    }
  };

  /**
   * Flushes queue for a given context, returning true if the flush was
   * performed, or false if there is no queue for the given context.
   *
   * @type {WPPriorityQueueFlush}
   *
   * @param {WPPriorityQueueContext} element Context object.
   *
   * @return {boolean} Whether flush was performed.
   */
  const flush = element => {
    const callback = waitingList.get(element);
    if (undefined === callback) {
      return false;
    }
    waitingList.delete(element);
    callback();
    return true;
  };

  /**
   * Clears the queue for a given context, cancelling the callbacks without
   * executing them. Returns `true` if there were scheduled callbacks to cancel,
   * or `false` if there was is no queue for the given context.
   *
   * @type {WPPriorityQueueFlush}
   *
   * @param {WPPriorityQueueContext} element Context object.
   *
   * @return {boolean} Whether any callbacks got cancelled.
   */
  const cancel = element => {
    return waitingList.delete(element);
  };

  /**
   * Reset the queue without running the pending callbacks.
   *
   * @type {WPPriorityQueueReset}
   */
  const reset = () => {
    waitingList.clear();
    isRunning = false;
  };
  return {
    add,
    flush,
    cancel,
    reset
  };
};
exports.createQueue = createQueue;
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