var toggle = document.createElement('div');
var sidebar = document.getElementById('sidebar');
toggle.innerHTML = '>';
toggle.classList.add('toggle-sidebar');
toggle.classList.add('open');
toggle.addEventListener('click', function() {
  sidebar.classList.toggle('hidden');
  toggle.classList.toggle('open');
  setTimeout(function() {
    toggle.innerHTML = sidebar.classList.contains('hidden') ? '<' : '>';
  }, 200);
});
sidebar.prepend(toggle);
toggle.click();