Provides waiting method for unfriendly async process (ex. no notify completion)

wait.js

/**
 * wait.js
 *
 * (c) 2018 koohq. Licensed under CC0.
 * https://creativecommons.org/publicdomain/zero/1.0/legalcode
 */
var Wait = (function() {

  function Wait(timeout, interval) {
    this.timeout = timeout;
    this.interval = interval;
  }

  var defaultTimeout = 1000;
  var defaultInterval = 10;

  Wait.prototype.until = function(condition) {
    return new Promise(function(resolve, reject) {
      if (condition()) { resolve(); return; }

      var interval = this.interval > 0 ? this.interval : defaultInterval;
      var timeout = this.timeout > 0 ? this.timeout : defaultTimeout;
      var limit = Math.ceil(timeout / interval);
      var count = 0;

      var intervalID = setInterval(function() {
        if (condition()) {
          clearInterval(intervalID);
          resolve();
        } else if(count >= limit) {
          clearInterval(intervalID);
          reject();
        }
        count++;
      }, interval);
    });
  };

  return Wait;
})();

wait.usage.js

/**
 * wait.usage.js
 *
 * (c) 2018 koohq. Licensed under CC0.
 * https://creativecommons.org/publicdomain/zero/1.0/legalcode
 */

// configure Wait
var timeoutMilliSeconds = 3000;
var intervalMilliSeconds = 100;
var wait = new Wait(timeoutMilliSeconds, intervalMilliSeconds);

// 'isReady' will be true sometime soon.
var isReady = false;
(function oneAsyncProcess() { setTimeout(function() { isReady = true; }, 1000); })();

// wait until 'isReady to be true'...
wait.until(function() { return isReady; })
  .then(function() { console.log('OK'); })
  .catch(function() { console.error('NG'); });