code: function btn (el, router) {
    var toggle = function (_) { return body.classList.toggle('close'); };
  
    el = getNode(el);
    on(el, 'click', function (e) {
      e.stopPropagation();
      toggle();
    });
  
    var sidebar = getNode('.sidebar');
  
    isMobile && on(body, 'click', function (_) { return body.classList.contains('close') && toggle(); }
    );
    on(sidebar, 'click', function (_) { return setTimeout((function (_) { return getAndActive(router, sidebar, true, true); }, 0)); }
    );
  }
docs: Toggle button