debounce.js

async function restoreWindow(window) {
  let cb;
  await new TimedPromise(resolve => {
    cb = new DebounceCallback(resolve);
    window.addEventListener("sizemodechange", cb);
    window.fullScreen = false;
  });
  window.removeEventListener("sizemodechange", cb);
}

windowstate.js

async function restoreFullscreen(window) {
  let cb;
  await new TimedPromise(resolve => {
    cb = () => {
      if (WindowState.from(window.windowState) == WindowState.Normal) {
        resolve();
      }
    };
    window.addEventListener("sizemodechange", cb);
    window.fullScreen = false;
  });
  window.removeEventListener("sizemodechange", cb);
}