README.md

onResizeStartEnd(
  () => {
    popup.classList.add("--hide");
  },
  () => {
    popup.classList.remove("--hide");
  },
  500
);

onResizeStartEndTimeout.js

/**
 * @author1 https://stackoverflow.com/questions/5489946/how-to-wait-for-the-end-of-resize-event-and-only-then-perform-an-action#answer-5490021
 * @author2 web.master-artem.ru
 * @param {Function} onResizeStartCallback
 * @param {Function} onResizeEndCallback
 * @param {Number} timeout
 */
export function onResizeStartEndTimeout(
  onResizeStartCallback,
  onResizeEndCallback,
  timeout
) {
  var doEndResizeCallback;
  var resizeStart = false;

  window.onresize = function () {
    // Если старт ещё не инициализирован
    if (!resizeStart) {
      // Инициализируем старт
      resizeStart = true;
      // И запускаем стартовый колбэк
      if (onResizeStartCallback) {
        onResizeStartCallback();
      }
    }

    clearTimeout(doEndResizeCallback);
    doEndResizeCallback = setTimeout(() => {
      if (onResizeEndCallback) {
        onResizeEndCallback();
      }
      resizeStart = false;
    }, timeout);
  };
}