Animated ARIA hamburger menu

/*Downloaded from https://www.codeseek.co/2kool2/animated-aria-hamburger-menu-kXVKKb */
/* Simple animated Peekaboo show-hide */

/* Generic styling (not required) */

.menu {
  display:block;
  width: 40px;
  height: 40px;
  border: 0 solid;
  background-color:#ddd;
}

.menu_svg {
  pointer-events: none;
}

.menu[aria-expanded="true"] {
  background-color: #1A1A1A;
  fill: #fff;
}


/* The heavy lifting is done by  3 statements */

.navigation {
  position: relative;
  margin: 0;
  padding: 0;
  transform: translate3d(0,0,0);
  backface-visibility: hidden;

  /* opacity has to finish before height to allow JS time to find first link */
  transition: visibility 0s ease-out, opacity .3s linear, max-height .5s ease-out;
  opacity: 0;
  visibility: hidden;
  max-height: 0;
  overflow: hidden;
}

.navigation[aria-hidden="true"] {
  transition-delay: .6s, 0s, 0s;
}

.navigation[aria-hidden="false"] {
  transition-delay: 0s, 0s, 0s;
  opacity: 1;
  visibility: visible;
  max-height: 12em;
}



/* More generic styling */

.navigation_title {
  margin: 0;
  padding: 0;
  position: absolute;
  left: -200em;
}

.navigation_list {
  margin: 0;
  padding: 0 2em;
}

.navigation_list li {
  width: 50%;
  float: left;
}

/*Downloaded from https://www.codeseek.co/2kool2/animated-aria-hamburger-menu-kXVKKb */
function peekaboo(w, d, linkBtnId) {

  // Peekaboo - show-hide toggle
  // Toggle a section using ARIA

  "use strict";
  var openLabel = "Open and skip to navigation bypassing site search";
  var closeLabel = "Close and hide navigation";


  var _getRegionObj = function (linkObj) {
    return d.getElementById(linkObj.hash.replace("#", "")) || !1;
  };


  var _setAriaStates = function (linkObj, regionObj, isExpanded) {
    w.requestAnimationFrame(function () {
      linkObj.setAttribute("aria-expanded", isExpanded);
      regionObj.setAttribute("aria-hidden", !isExpanded);
      linkObj.setAttribute("aria-label", isExpanded ? closeLabel : openLabel);
    });
  };
 

  var _toggleAriaStates = function (e) {

    e.preventDefault();
    var linkObj = e.target;
    var expanded = linkObj.getAttribute("aria-expanded") || !1;

    if (expanded) { // string "false" is boolean true here
      
      var regionObj = _getRegionObj(linkObj);
      if (regionObj) {

        // convert to boolean
        expanded = expanded === "true"; 
        _setAriaStates(linkObj, regionObj, !expanded);
        if (expanded) {
          linkObj.focus();
        } else {

          // Small delay required for focusable object to reappear in DOM
          // (transitionend event would have CSS dependencies)
          setTimeout(function() {
            (regionObj.querySelector("a") || regionObj).focus();
          }, 100);
        }
      }
    }
  };


  var _addAriaAttributes = function (linkObj) {

    var regionObj = _getRegionObj(linkObj);
    if (regionObj) {
      linkObj.setAttribute("aria-controls", regionObj.id);
      regionObj.setAttribute("aria-controlledby", linkObj.id);
      _setAriaStates(linkObj, regionObj, false);
    }
    return regionObj;
  };


  var initialise = function () {

    var anchor = d.getElementById(linkBtnId);
    if (anchor && _addAriaAttributes(anchor)) {
        anchor.addEventListener("click", _toggleAriaStates, !1);
    }
  };

  return initialise();

}

peekaboo(window, document, "hamburger");