module.exports = function() {
  // Borrowed wholesale from https://github.com/defunkt/jquery-pjax
  return (
    window.history &&
    window.history.pushState &&
    window.history.replaceState &&
    // pushState isn’t reliable on iOS until 5.
    !navigator.userAgent.match(
      /((iPod|iPhone|iPad).+\bOS\s+[1-4]\D|WebApps\/.+CFNetwork)/
    )
  );
};