var drawer = function() {
    if (!Element.prototype.closest) {
        if (!Element.prototype.matches) {
            Element.prototype.matches = Element.prototype.msMatchesSelector || Element.prototype.webkitMatchesSelector;
        }
        Element.prototype.closest = function(s) {
            var el = this;
            var ancestor = this;
            if (!document.documentElement.contains(el))
                return null;
            do {
                if (ancestor.matches(s))
                    return ancestor;
                ancestor = ancestor.parentElement;
            } while (ancestor !== null);
            return null;
        }
        ;
    }

    var settings = {
        speedOpen: 50,
        speedClose: 350,
        activeClass: 'is-active',
        visibleClass: 'is-visible',
        selectorTarget: '[data-drawer-target]',
        selectorTrigger: '[data-drawer-trigger]',
        selectorClose: '[data-drawer-close]',
    };
    var toggleccessibility = function(event) {
        if (event.getAttribute('aria-expanded') === 'true') {
            event.setAttribute('aria-expanded', false);
        } else {
            event.setAttribute('aria-expanded', true);
        }
    };
    var openDrawer = function(trigger) {
        var target = document.getElementById(trigger.getAttribute('aria-controls'));
        target.classList.add(settings.activeClass);
        document.documentElement.style.overflow = 'hidden';
        toggleccessibility(trigger);
        setTimeout(function() {
            target.classList.add(settings.visibleClass);
        }, settings.speedOpen);
    };
    var closeDrawer = function(event) {
        var closestParent = event.closest(settings.selectorTarget)
            , childrenTrigger = document.querySelector('[aria-controls="' + closestParent.id + '"');
        closestParent.classList.remove(settings.visibleClass);
        document.documentElement.style.overflow = '';
        toggleccessibility(childrenTrigger);
        setTimeout(function() {
            closestParent.classList.remove(settings.activeClass);
        }, settings.speedClose);
    };
    var clickHandler = function(event) {
        var toggle = event.target
            , open = toggle.closest(settings.selectorTrigger)
            , close = toggle.closest(settings.selectorClose);
        if (open) {
            openDrawer(open);
        }
        if (close) {
            closeDrawer(close);
        }
        if (open || close) {
            event.preventDefault();
        }
    };
    // var keydownHandler = function(event) {
    //     if (event.key === 'Escape' || event.keyCode === 27) {
    //         var drawers = document.querySelectorAll(settings.selectorTarget), i;
    //         for (i = 0; i < drawers.length; ++i) {
    //             if (drawers[i].classList.contains(settings.activeClass)) {
    //                 closeDrawer(drawers[i]);
    //             }
    //         }
    //     }
    // };
    document.addEventListener('click', clickHandler, false);
    // document.addEventListener('keydown', keydownHandler, false);
};
drawer();