function initMobileMenu () {
    var mobileBar = document.getElementById('mobile-bar')
    var sidebar = document.querySelector('.sidebar')
    var menuButton = mobileBar.querySelector('.menu-button')

    menuButton.addEventListener('click', function () {
      sidebar.classList.toggle('open')
    })

    document.body.addEventListener('click', function (e) {
      if (e.target !== menuButton && !sidebar.contains(e.target)) {
        sidebar.classList.remove('open')
      }
    })

    // Toggle sidebar on swipe
    var start = {}, end = {}

    document.body.addEventListener('touchstart', function (e) {
      start.x = e.changedTouches[0].clientX
      start.y = e.changedTouches[0].clientY
    })

    document.body.addEventListener('touchend', function (e) {
      end.y = e.changedTouches[0].clientY
      end.x = e.changedTouches[0].clientX

      var xDiff = end.x - start.x
      var yDiff = end.y - start.y

      if (Math.abs(xDiff) > Math.abs(yDiff)) {
        if (xDiff > 0 && start.x <= 80) sidebar.classList.add('open')
        else sidebar.classList.remove('open')
      }
    })
  }
Mobile burger menu button and gesture for toggling sidebar