/*
 * HTML5Sortable package
 * https://github.com/lukasoppermann/html5sortable
 *
 * Maintained by Lukas Oppermann <lukas@vea.re>
 *
 * Released under the MIT license.
 */
var sortable = (function () {
    'use strict';

    /**
     * Get or set data on element
     * @param {HTMLElement} element
     * @param {string} key
     * @param {any} value
     * @return {*}
     */
    function addData(element, key, value) {
        if (value === undefined) {
            return element && element.h5s && element.h5s.data && element.h5s.data[key];
        }
        else {
            element.h5s = element.h5s || {};
            element.h5s.data = element.h5s.data || {};
            element.h5s.data[key] = value;
        }
    }
    /**
     * Remove data from element
     * @param {HTMLElement} element
     */
    function removeData(element) {
        if (element.h5s) {
            delete element.h5s.data;
        }
    }

    function _filter (nodes, selector) {
        if (!(nodes instanceof NodeList || nodes instanceof HTMLCollection || nodes instanceof Array)) {
            throw new Error('You must provide a nodeList/HTMLCollection/Array of elements to be filtered.');
        }
        if (typeof selector !== 'string') {
            return Array.from(nodes);
        }
        return Array.from(nodes).filter(function (item) { return item.nodeType === 1 && item.matches(selector); });
    }

    /* eslint-env browser */
    var stores = new Map();
    /**
     * Stores data & configurations per Sortable
     * @param {Object} config
     */
    var Store = (function () {
        function Store() {
            this._config = new Map(); // eslint-disable-line no-undef
            this._placeholder = undefined; // eslint-disable-line no-undef
            this._data = new Map(); // eslint-disable-line no-undef
        }
        Object.defineProperty(Store.prototype, "config", {
            /**
             * get the configuration map of a class instance
             * @method config
             * @return {object}
             */
            get: function () {
                // transform Map to object
                var config = {};
                this._config.forEach(function (value, key) {
                    config[key] = value;
                });
                // return object
                return config;
            },
            /**
             * set the configuration of a class instance
             * @method config
             * @param {object} config object of configurations
             */
            set: function (config) {
                if (typeof config !== 'object') {
                    throw new Error('You must provide a valid configuration object to the config setter.');
                }
                // combine config with default
                var mergedConfig = Object.assign({}, config);
                // add config to map
                this._config = new Map(Object.entries(mergedConfig));
            },
            enumerable: true,
            configurable: true
        });
        /**
         * set individual configuration of a class instance
         * @method setConfig
         * @param  key valid configuration key
         * @param  value any value
         * @return void
         */
        Store.prototype.setConfig = function (key, value) {
            if (!this._config.has(key)) {
                throw new Error("Trying to set invalid configuration item: " + key);
            }
            // set config
            this._config.set(key, value);
        };
        /**
         * get an individual configuration of a class instance
         * @method getConfig
         * @param  key valid configuration key
         * @return any configuration value
         */
        Store.prototype.getConfig = function (key) {
            if (!this._config.has(key)) {
                throw new Error("Invalid configuration item requested: " + key);
            }
            return this._config.get(key);
        };
        Object.defineProperty(Store.prototype, "placeholder", {
            /**
             * get the placeholder for a class instance
             * @method placeholder
             * @return {HTMLElement|null}
             */
            get: function () {
                return this._placeholder;
            },
            /**
             * set the placeholder for a class instance
             * @method placeholder
             * @param {HTMLElement} placeholder
             * @return {void}
             */
            set: function (placeholder) {
                if (!(placeholder instanceof HTMLElement) && placeholder !== null) {
                    throw new Error('A placeholder must be an html element or null.');
                }
                this._placeholder = placeholder;
            },
            enumerable: true,
            configurable: true
        });
        /**
         * set an data entry
         * @method setData
         * @param {string} key
         * @param {any} value
         * @return {void}
         */
        Store.prototype.setData = function (key, value) {
            if (typeof key !== 'string') {
                throw new Error("The key must be a string.");
            }
            this._data.set(key, value);
        };
        /**
         * get an data entry
         * @method getData
         * @param {string} key an existing key
         * @return {any}
         */
        Store.prototype.getData = function (key) {
            if (typeof key !== 'string') {
                throw new Error("The key must be a string.");
            }
            return this._data.get(key);
        };
        /**
         * delete an data entry
         * @method deleteData
         * @param {string} key an existing key
         * @return {boolean}
         */
        Store.prototype.deleteData = function (key) {
            if (typeof key !== 'string') {
                throw new Error("The key must be a string.");
            }
            return this._data.delete(key);
        };
        return Store;
    }());
    function store (sortableElement) {
        // if sortableElement is wrong type
        if (!(sortableElement instanceof HTMLElement)) {
            throw new Error('Please provide a sortable to the store function.');
        }
        // create new instance if not avilable
        if (!stores.has(sortableElement)) {
            stores.set(sortableElement, new Store());
        }
        // return instance
        return stores.get(sortableElement);
    }

    /**
     * @param {Array|HTMLElement} element
     * @param {Function} callback
     * @param {string} event
     */
    function addEventListener(element, eventName, callback) {
        if (element instanceof Array) {
            for (var i = 0; i < element.length; ++i) {
                addEventListener(element[i], eventName, callback);
            }
            return;
        }
        element.addEventListener(eventName, callback);
        store(element).setData("event" + eventName, callback);
    }
    /**
     * @param {Array<HTMLElement>|HTMLElement} element
     * @param {string} eventName
     */
    function removeEventListener(element, eventName) {
        if (element instanceof Array) {
            for (var i = 0; i < element.length; ++i) {
                removeEventListener(element[i], eventName);
            }
            return;
        }
        element.removeEventListener(eventName, store(element).getData("event" + eventName));
        store(element).deleteData("event" + eventName);
    }

    /**
     * @param {Array<HTMLElement>|HTMLElement} element
     * @param {string} attribute
     * @param {string} value
     */
    function addAttribute(element, attribute, value) {
        if (element instanceof Array) {
            for (var i = 0; i < element.length; ++i) {
                addAttribute(element[i], attribute, value);
            }
            return;
        }
        element.setAttribute(attribute, value);
    }
    /**
     * @param {Array|HTMLElement} element
     * @param {string} attribute
     */
    function removeAttribute(element, attribute) {
        if (element instanceof Array) {
            for (var i = 0; i < element.length; ++i) {
                removeAttribute(element[i], attribute);
            }
            return;
        }
        element.removeAttribute(attribute);
    }

    function offset (element) {
        if (!element.parentElement || element.getClientRects().length === 0) {
            throw new Error('target element must be part of the dom');
        }
        var rect = element.getClientRects()[0];
        return {
            left: rect.left + window.pageXOffset,
            right: rect.right + window.pageXOffset,
            top: rect.top + window.pageYOffset,
            bottom: rect.bottom + window.pageYOffset
        };
    }

    function _debounce (func, wait) {
        if (wait === void 0) { wait = 0; }
        var timeout;
        return function () {
            var args = [];
            for (var _i = 0; _i < arguments.length; _i++) {
                args[_i - 0] = arguments[_i];
            }
            clearTimeout(timeout);
            timeout = setTimeout(function () {
                func.apply(void 0, args);
            }, wait);
        };
    }

    function index (element, elementList) {
        if (!(element instanceof HTMLElement) || !(elementList instanceof NodeList || elementList instanceof HTMLCollection || elementList instanceof Array)) {
            throw new Error('You must provide an element and a list of elements.');
        }
        return Array.from(elementList).indexOf(element);
    }

    function isInDom (element) {
        if (!(element instanceof HTMLElement)) {
            throw new Error('Element is not a node element.');
        }
        return element.parentNode !== null;
    }

    /* eslint-env browser */
    /**
     * Insert node before or after target
     * @param {HTMLElement} referenceNode - reference element
     * @param {HTMLElement} newElement - element to be inserted
     * @param {String} position - insert before or after reference element
     */
    var insertNode = function (referenceNode, newElement, position) {
        if (!(referenceNode instanceof HTMLElement) || !(referenceNode.parentElement instanceof HTMLElement)) {
            throw new Error('target and element must be a node');
        }
        referenceNode.parentElement.insertBefore(newElement, (position === 'before' ? referenceNode : referenceNode.nextElementSibling));
    };
    /**
     * Insert before target
     * @param {HTMLElement} target
     * @param {HTMLElement} element
     */
    var insertBefore = function (target, element) { return insertNode(target, element, 'before'); };
    /**
     * Insert after target
     * @param {HTMLElement} target
     * @param {HTMLElement} element
     */
    var insertAfter = function (target, element) { return insertNode(target, element, 'after'); };

    function _serialize (sortableContainer, customItemSerializer, customContainerSerializer) {
        if (customItemSerializer === void 0) { customItemSerializer = function (serializedItem, sortableContainer) { return serializedItem; }; }
        if (customContainerSerializer === void 0) { customContainerSerializer = function (serializedContainer) { return serializedContainer; }; }
        // check for valid sortableContainer
        if (!(sortableContainer instanceof HTMLElement) || !sortableContainer.isSortable === true) {
            throw new Error('You need to provide a sortableContainer to be serialized.');
        }
        // check for valid serializers
        if (typeof customItemSerializer !== 'function' || typeof customContainerSerializer !== 'function') {
            throw new Error('You need to provide a valid serializer for items and the container.');
        }
        // get options
        var options = addData(sortableContainer, 'opts');
        var item = options.items;
        // serialize container
        var items = _filter(sortableContainer.children, item);
        var serializedItems = items.map(function (item) {
            return {
                parent: sortableContainer,
                node: item,
                html: item.outerHTML,
                index: index(item, items)
            };
        });
        // serialize container
        var container = {
            node: sortableContainer,
            itemCount: serializedItems.length
        };
        return {
            container: customContainerSerializer(container),
            items: serializedItems.map(function (item) { return customItemSerializer(item, sortableContainer); })
        };
    }

    function _makePlaceholder (sortableElement, placeholder, placeholderClass) {
        if (placeholderClass === void 0) { placeholderClass = 'sortable-placeholder'; }
        if (!(sortableElement instanceof HTMLElement)) {
            throw new Error('You must provide a valid element as a sortable.');
        }
        // if placeholder is not an element
        if (!(placeholder instanceof HTMLElement) && placeholder !== undefined) {
            throw new Error('You must provide a valid element as a placeholder or set ot to undefined.');
        }
        // if no placeholder element is given
        if (placeholder === undefined) {
            if (['UL', 'OL'].includes(sortableElement.tagName)) {
                placeholder = document.createElement('li');
            }
            else if (['TABLE', 'TBODY'].includes(sortableElement.tagName)) {
                placeholder = document.createElement('tr');
                // set colspan to always all rows, otherwise the item can only be dropped in first column
                placeholder.innerHTML = '<td colspan="100"></td>';
            }
            else {
                placeholder = document.createElement('div');
            }
        }
        // add classes to placeholder
        if (typeof placeholderClass === 'string') {
            (_a = placeholder.classList).add.apply(_a, placeholderClass.split(' '));
        }
        return placeholder;
        var _a;
    }

    function _getElementHeight (element) {
        if (!(element instanceof HTMLElement)) {
            throw new Error('You must provide a valid dom element');
        }
        // get calculated style of element
        var style = window.getComputedStyle(element);
        // pick applicable properties, convert to int and reduce by adding
        return ['height', 'padding-top', 'padding-bottom']
            .map(function (key) {
            var int = parseInt(style.getPropertyValue(key), 10);
            return isNaN(int) ? 0 : int;
        })
            .reduce(function (sum, value) { return sum + value; });
    }

    function _getHandles (items, selector) {
        if (!(items instanceof Array)) {
            throw new Error('You must provide a Array of HTMLElements to be filtered.');
        }
        if (typeof selector !== 'string') {
            return items;
        }
        return items
            .filter(function (item) {
            return item.querySelector(selector) instanceof HTMLElement;
        })
            .map(function (item) {
            return item.querySelector(selector);
        });
    }

    /**
     * defaultDragImage returns the current item as dragged image
     * @param {HTMLElement} draggedElement - the item that the user drags
     * @param {object} elementOffset - an object with the offsets top, left, right & bottom
     * @param {Event} event - the original drag event object
     * @return {object} with element, posX and posY properties
     */
    var defaultDragImage = function (draggedElement, elementOffset, event) {
        return {
            element: draggedElement,
            posX: event.pageX - elementOffset.left,
            posY: event.pageY - elementOffset.top
        };
    };
    function setDragImage (event, draggedElement, customDragImage) {
        // check if event is provided
        if (!(event instanceof Event)) {
            throw new Error('setDragImage requires a DragEvent as the first argument.');
        }
        // check if draggedElement is provided
        if (!(draggedElement instanceof HTMLElement)) {
            throw new Error('setDragImage requires the dragged element as the second argument.');
        }
        // set default function of none provided
        if (!customDragImage) {
            customDragImage = defaultDragImage;
        }
        // check if setDragImage method is available
        if (event.dataTransfer && event.dataTransfer.setDragImage) {
            // get the elements offset
            var elementOffset = offset(draggedElement);
            // get the dragImage
            var dragImage = customDragImage(draggedElement, elementOffset, event);
            // check if custom function returns correct values
            if (!(dragImage.element instanceof HTMLElement) || typeof dragImage.posX !== 'number' || typeof dragImage.posY !== 'number') {
                throw new Error('The customDragImage function you provided must return and object with the properties element[string], posX[integer], posY[integer].');
            }
            // needs to be set for HTML5 drag & drop to work
            event.dataTransfer.effectAllowed = 'copyMove';
            // Firefox requires it to use the event target's id for the data
            event.dataTransfer.setData('text/plain', event.target.id);
            // set the drag image on the event
            event.dataTransfer.setDragImage(dragImage.element, dragImage.posX, dragImage.posY);
        }
    }

    function _listsConnected (destination, origin) {
        // check if valid sortable
        if (destination.isSortable === true) {
            var acceptFrom = store(destination).getConfig('acceptFrom');
            // check if acceptFrom is valid
            if (acceptFrom !== null && acceptFrom !== false && typeof acceptFrom !== 'string') {
                throw new Error('HTML5Sortable: Wrong argument, "acceptFrom" must be "null", "false", or a valid selector string.');
            }
            if (acceptFrom !== null) {
                return acceptFrom !== false && acceptFrom.split(',').filter(function (sel) {
                    return sel.length > 0 && origin.matches(sel);
                }).length > 0;
            }
            // drop in same list
            if (destination === origin) {
                return true;
            }
            // check if lists are connected with connectWith
            if (store(destination).getConfig('connectWith') !== undefined && store(destination).getConfig('connectWith') !== null) {
                return store(destination).getConfig('connectWith') === store(origin).getConfig('connectWith');
            }
        }
        return false;
    }

    var defaultConfiguration = {
        items: null,
        // deprecated
        connectWith: null,
        // deprecated
        disableIEFix: null,
        acceptFrom: null,
        copy: false,
        placeholder: null,
        placeholderClass: 'sortable-placeholder',
        draggingClass: 'sortable-dragging',
        hoverClass: false,
        debounce: 0,
        throttleTime: 100,
        maxItems: 0,
        itemSerializer: undefined,
        containerSerializer: undefined,
        customDragImage: null
    };

    /**
     * make sure a function is only called once within the given amount of time
     * @param {Function} fn the function to throttle
     * @param {number} threshold time limit for throttling
     */
    // must use function to keep this context
    function _throttle (fn, threshold) {
        var _this = this;
        if (threshold === void 0) { threshold = 250; }
        // check function
        if (typeof fn !== 'function') {
            throw new Error('You must provide a function as the first argument for throttle.');
        }
        // check threshold
        if (typeof threshold !== 'number') {
            throw new Error('You must provide a number as the second argument for throttle.');
        }
        var lastEventTimestamp = null;
        return function () {
            var args = [];
            for (var _i = 0; _i < arguments.length; _i++) {
                args[_i - 0] = arguments[_i];
            }
            var now = Date.now();
            if (lastEventTimestamp === null || now - lastEventTimestamp >= threshold) {
                lastEventTimestamp = now;
                fn.apply(_this, args);
            }
        };
    }

    function enableHoverClass (sortableContainer, enable) {
        if (typeof store(sortableContainer).getConfig('hoverClass') === 'string') {
            var hoverClasses_1 = store(sortableContainer).getConfig('hoverClass').split(' ');
            // add class on hover
            if (enable === true) {
                addEventListener(sortableContainer, 'mousemove', _throttle(function (event) {
                    // check of no mouse button was pressed when mousemove started == no drag
                    if (event.buttons === 0) {
                        _filter(sortableContainer.children, store(sortableContainer).getConfig('items')).forEach(function (item) {
                            if (item !== event.target) {
                                (_a = item.classList).remove.apply(_a, hoverClasses_1);
                            }
                            else {
                                (_b = item.classList).add.apply(_b, hoverClasses_1);
                            }
                            var _a, _b;
                        });
                    }
                }, store(sortableContainer).getConfig('throttleTime')));
                // remove class on leave
                addEventListener(sortableContainer, 'mouseleave', function () {
                    _filter(sortableContainer.children, store(sortableContainer).getConfig('items')).forEach(function (item) {
                        (_a = item.classList).remove.apply(_a, hoverClasses_1);
                        var _a;
                    });
                });
            }
            else {
                removeEventListener(sortableContainer, 'mousemove');
                removeEventListener(sortableContainer, 'mouseleave');
            }
        }
    }

    /* eslint-env browser */
    /*
     * variables global to the plugin
     */
    var dragging;
    var draggingHeight;
    /*
     * Keeps track of the initialy selected list, where 'dragstart' event was triggered
     * It allows us to move the data in between individual Sortable List instances
     */
    // Origin List - data from before any item was changed
    var originContainer;
    var originIndex;
    var originElementIndex;
    var originItemsBeforeUpdate;
    // Destination List - data from before any item was changed
    var destinationItemsBeforeUpdate;
    /**
     * remove event handlers from items
     * @param {Array|NodeList} items
     */
    var _removeItemEvents = function (items) {
        removeEventListener(items, 'dragstart');
        removeEventListener(items, 'dragend');
        removeEventListener(items, 'dragover');
        removeEventListener(items, 'dragenter');
        removeEventListener(items, 'drop');
        removeEventListener(items, 'mouseenter');
        removeEventListener(items, 'mouseleave');
    };
    /**
     * _getDragging returns the current element to drag or
     * a copy of the element.
     * Is Copy Active for sortable
     * @param {HTMLElement} draggedItem - the item that the user drags
     * @param {HTMLElement} sortable a single sortable
     */
    var _getDragging = function (draggedItem, sortable) {
        var ditem = draggedItem;
        if (store(sortable).getConfig('copy') === true) {
            ditem = draggedItem.cloneNode(true);
            addAttribute(ditem, 'aria-copied', 'true');
            draggedItem.parentElement.appendChild(ditem);
            ditem.style.display = 'none';
            ditem.oldDisplay = draggedItem.style.display;
        }
        return ditem;
    };
    /**
     * Remove data from sortable
     * @param {HTMLElement} sortable a single sortable
     */
    var _removeSortableData = function (sortable) {
        removeData(sortable);
        removeAttribute(sortable, 'aria-dropeffect');
    };
    /**
     * Remove data from items
     * @param {Array<HTMLElement>|HTMLElement} items
     */
    var _removeItemData = function (items) {
        removeAttribute(items, 'aria-grabbed');
        removeAttribute(items, 'aria-copied');
        removeAttribute(items, 'draggable');
        removeAttribute(items, 'role');
    };
    /**
     * find sortable from element. travels up parent element until found or null.
     * @param {HTMLElement} element a single sortable
     */
    function findSortable(element) {
        while (element.isSortable !== true) {
            element = element.parentElement;
        }
        return element;
    }
    /**
     * Dragging event is on the sortable element. finds the top child that
     * contains the element.
     * @param {HTMLElement} sortableElement a single sortable
     * @param {HTMLElement} element is that being dragged
     */
    function findDragElement(sortableElement, element) {
        var options = addData(sortableElement, 'opts');
        var items = _filter(sortableElement.children, options.items);
        var itemlist = items.filter(function (ele) {
            return ele.contains(element);
        });
        return itemlist.length > 0 ? itemlist[0] : element;
    }
    /**
     * Destroy the sortable
     * @param {HTMLElement} sortableElement a single sortable
     */
    var _destroySortable = function (sortableElement) {
        var opts = addData(sortableElement, 'opts') || {};
        var items = _filter(sortableElement.children, opts.items);
        var handles = _getHandles(items, opts.handle);
        // remove event handlers & data from sortable
        removeEventListener(sortableElement, 'dragover');
        removeEventListener(sortableElement, 'dragenter');
        removeEventListener(sortableElement, 'drop');
        // remove event data from sortable
        _removeSortableData(sortableElement);
        // remove event handlers & data from items
        removeEventListener(handles, 'mousedown');
        _removeItemEvents(items);
        _removeItemData(items);
    };
    /**
     * Enable the sortable
     * @param {HTMLElement} sortableElement a single sortable
     */
    var _enableSortable = function (sortableElement) {
        var opts = addData(sortableElement, 'opts');
        var items = _filter(sortableElement.children, opts.items);
        var handles = _getHandles(items, opts.handle);
        addAttribute(sortableElement, 'aria-dropeffect', 'move');
        addData(sortableElement, '_disabled', 'false');
        addAttribute(handles, 'draggable', 'true');
        // @todo: remove this fix
        // IE FIX for ghost
        // can be disabled as it has the side effect that other events
        // (e.g. click) will be ignored
        if (opts.disableIEFix === false) {
            var spanEl = (document || window.document).createElement('span');
            if (typeof spanEl.dragDrop === 'function') {
                addEventListener(handles, 'mousedown', function () {
                    if (items.indexOf(this) !== -1) {
                        this.dragDrop();
                    }
                    else {
                        var parent = this.parentElement;
                        while (items.indexOf(parent) === -1) {
                            parent = parent.parentElement;
                        }
                        parent.dragDrop();
                    }
                });
            }
        }
    };
    /**
     * Disable the sortable
     * @param {HTMLElement} sortableElement a single sortable
     */
    var _disableSortable = function (sortableElement) {
        var opts = addData(sortableElement, 'opts');
        var items = _filter(sortableElement.children, opts.items);
        var handles = _getHandles(items, opts.handle);
        addAttribute(sortableElement, 'aria-dropeffect', 'none');
        addData(sortableElement, '_disabled', 'true');
        addAttribute(handles, 'draggable', 'false');
        removeEventListener(handles, 'mousedown');
    };
    /**
     * Reload the sortable
     * @param {HTMLElement} sortableElement a single sortable
     * @description events need to be removed to not be double bound
     */
    var _reloadSortable = function (sortableElement) {
        var opts = addData(sortableElement, 'opts');
        var items = _filter(sortableElement.children, opts.items);
        var handles = _getHandles(items, opts.handle);
        addData(sortableElement, '_disabled', 'false');
        // remove event handlers from items
        _removeItemEvents(items);
        removeEventListener(handles, 'mousedown');
        // remove event handlers from sortable
        removeEventListener(sortableElement, 'dragover');
        removeEventListener(sortableElement, 'dragenter');
        removeEventListener(sortableElement, 'drop');
    };
    /**
     * Public sortable object
     * @param {Array|NodeList} sortableElements
     * @param {object|string} options|method
     */
    function sortable(sortableElements, options) {
        // get method string to see if a method is called
        var method = String(options);
        options = options || {};
        // check if the user provided a selector instead of an element
        if (typeof sortableElements === 'string') {
            sortableElements = document.querySelectorAll(sortableElements);
        }
        // if the user provided an element, return it in an array to keep the return value consistant
        if (sortableElements instanceof HTMLElement) {
            sortableElements = [sortableElements];
        }
        sortableElements = Array.prototype.slice.call(sortableElements);
        if (/serialize/.test(method)) {
            return sortableElements.map(function (sortableContainer) {
                var opts = addData(sortableContainer, 'opts');
                return _serialize(sortableContainer, opts.itemSerializer, opts.containerSerializer);
            });
        }
        sortableElements.forEach(function (sortableElement) {
            if (/enable|disable|destroy/.test(method)) {
                return sortable[method](sortableElement);
            }
            // log deprecation
            ['connectWith', 'disableIEFix'].forEach(function (configKey) {
                if (options.hasOwnProperty(configKey) && options[configKey] !== null) {
                    console.warn("HTML5Sortable: You are using the deprecated configuration \"" + configKey + "\". This will be removed in an upcoming version, make sure to migrate to the new options when updating.");
                }
            });
            // merge options with default options
            options = Object.assign({}, defaultConfiguration, store(sortableElement).config, options);
            // init data store for sortable
            store(sortableElement).config = options;
            // set options on sortable
            addData(sortableElement, 'opts', options);
            // property to define as sortable
            sortableElement.isSortable = true;
            // reset sortable
            _reloadSortable(sortableElement);
            // initialize
            var listItems = _filter(sortableElement.children, options.items);
            // create element if user defined a placeholder element as a string
            var customPlaceholder;
            if (options.placeholder !== null && options.placeholder !== undefined) {
                var tempContainer = document.createElement(sortableElement.tagName);
                tempContainer.innerHTML = options.placeholder;
                customPlaceholder = tempContainer.children[0];
            }
            // add placeholder
            store(sortableElement).placeholder = _makePlaceholder(sortableElement, customPlaceholder, options.placeholderClass);
            addData(sortableElement, 'items', options.items);
            if (options.acceptFrom) {
                addData(sortableElement, 'acceptFrom', options.acceptFrom);
            }
            else if (options.connectWith) {
                addData(sortableElement, 'connectWith', options.connectWith);
            }
            _enableSortable(sortableElement);
            addAttribute(listItems, 'role', 'option');
            addAttribute(listItems, 'aria-grabbed', 'false');
            // enable hover class
            enableHoverClass(sortableElement, true);
            /*
             Handle drag events on draggable items
             Handle is set at the sortableElement level as it will bubble up
             from the item
             */
            addEventListener(sortableElement, 'dragstart', function (e) {
                // ignore dragstart events
                if (e.target.isSortable === true) {
                    return;
                }
                e.stopImmediatePropagation();
                if ((options.handle && !e.target.matches(options.handle)) || e.target.getAttribute('draggable') === 'false') {
                    return;
                }
                var sortableContainer = findSortable(e.target);
                var dragItem = findDragElement(sortableContainer, e.target);
                // grab values
                originItemsBeforeUpdate = _filter(sortableContainer.children, options.items);
                originIndex = originItemsBeforeUpdate.indexOf(dragItem);
                originElementIndex = index(dragItem, sortableContainer.children);
                originContainer = sortableContainer;
                // add transparent clone or other ghost to cursor
                setDragImage(e, dragItem, options.customDragImage);
                // cache selsection & add attr for dragging
                draggingHeight = _getElementHeight(dragItem);
                dragItem.classList.add(options.draggingClass);
                dragging = _getDragging(dragItem, sortableContainer);
                addAttribute(dragging, 'aria-grabbed', 'true');
                // dispatch sortstart event on each element in group
                sortableContainer.dispatchEvent(new CustomEvent('sortstart', {
                    detail: {
                        origin: {
                            elementIndex: originElementIndex,
                            index: originIndex,
                            container: originContainer
                        },
                        item: dragging
                    }
                }));
            });
            /*
             We are capturing targetSortable before modifications with 'dragenter' event
            */
            addEventListener(sortableElement, 'dragenter', function (e) {
                if (e.target.isSortable === true) {
                    return;
                }
                var sortableContainer = findSortable(e.target);
                destinationItemsBeforeUpdate = _filter(sortableContainer.children, addData(sortableContainer, 'items'))
                    .filter(function (item) { return item !== store(sortableElement).placeholder; });
            });
            /*
             * Dragend Event - https://developer.mozilla.org/en-US/docs/Web/Events/dragend
             * Fires each time dragEvent end, or ESC pressed
             * We are using it to clean up any draggable elements and placeholders
             */
            addEventListener(sortableElement, 'dragend', function (e) {
                if (!dragging) {
                    return;
                }
                dragging.classList.remove(options.draggingClass);
                addAttribute(dragging, 'aria-grabbed', 'false');
                if (dragging.getAttribute('aria-copied') === 'true' && addData(dragging, 'dropped') !== 'true') {
                    dragging.remove();
                }
                dragging.style.display = dragging.oldDisplay;
                delete dragging.oldDisplay;
                var visiblePlaceholder = Array.from(stores.values()).map(function (data) { return data.placeholder; })
                    .filter(function (placeholder) { return placeholder instanceof HTMLElement; })
                    .filter(isInDom)[0];
                if (visiblePlaceholder) {
                    visiblePlaceholder.remove();
                }
                // dispatch sortstart event on each element in group
                sortableElement.dispatchEvent(new CustomEvent('sortstop', {
                    detail: {
                        origin: {
                            elementIndex: originElementIndex,
                            index: originIndex,
                            container: originContainer
                        },
                        item: dragging
                    }
                }));
                dragging = null;
                draggingHeight = null;
            });
            /*
             * Drop Event - https://developer.mozilla.org/en-US/docs/Web/Events/drop
             * Fires when valid drop target area is hit
             */
            addEventListener(sortableElement, 'drop', function (e) {
                if (!_listsConnected(sortableElement, dragging.parentElement)) {
                    return;
                }
                e.preventDefault();
                e.stopPropagation();
                addData(dragging, 'dropped', 'true');
                // get the one placeholder that is currently visible
                var visiblePlaceholder = Array.from(stores.values()).map(function (data) {
                    return data.placeholder;
                })
                    .filter(function (placeholder) { return placeholder instanceof HTMLElement; })
                    .filter(isInDom)[0];
                // attach element after placeholder
                insertAfter(visiblePlaceholder, dragging);
                // remove placeholder from dom
                visiblePlaceholder.remove();
                /*
                 * Fires Custom Event - 'sortstop'
                 */
                sortableElement.dispatchEvent(new CustomEvent('sortstop', {
                    detail: {
                        origin: {
                            elementIndex: originElementIndex,
                            index: originIndex,
                            container: originContainer
                        },
                        item: dragging
                    }
                }));
                var placeholder = store(sortableElement).placeholder;
                var originItems = _filter(originContainer.children, options.items)
                    .filter(function (item) { return item !== placeholder; });
                var destinationContainer = this.isSortable === true ? this : this.parentElement;
                var destinationItems = _filter(destinationContainer.children, addData(destinationContainer, 'items'))
                    .filter(function (item) { return item !== placeholder; });
                var destinationElementIndex = index(dragging, Array.from(dragging.parentElement.children)
                    .filter(function (item) { return item !== placeholder; }));
                var destinationIndex = index(dragging, destinationItems);
                /*
                 * When a list item changed container lists or index within a list
                 * Fires Custom Event - 'sortupdate'
                 */
                if (originElementIndex !== destinationElementIndex || originContainer !== destinationContainer) {
                    sortableElement.dispatchEvent(new CustomEvent('sortupdate', {
                        detail: {
                            origin: {
                                elementIndex: originElementIndex,
                                index: originIndex,
                                container: originContainer,
                                itemsBeforeUpdate: originItemsBeforeUpdate,
                                items: originItems
                            },
                            destination: {
                                index: destinationIndex,
                                elementIndex: destinationElementIndex,
                                container: destinationContainer,
                                itemsBeforeUpdate: destinationItemsBeforeUpdate,
                                items: destinationItems
                            },
                            item: dragging
                        }
                    }));
                }
            });
            var debouncedDragOverEnter = _debounce(function (sortableElement, element, pageY) {
                if (!dragging) {
                    return;
                }
                // set placeholder height if forcePlaceholderSize option is set
                if (options.forcePlaceholderSize) {
                    store(sortableElement).placeholder.style.height = draggingHeight + 'px';
                }
                // if element the draggedItem is dragged onto is within the array of all elements in list
                // (not only items, but also disabled, etc.)
                if (Array.from(sortableElement.children).indexOf(element) > -1) {
                    var thisHeight = _getElementHeight(element);
                    var placeholderIndex = index(store(sortableElement).placeholder, element.parentElement.children);
                    var thisIndex = index(element, element.parentElement.children);
                    // Check if `element` is bigger than the draggable. If it is, we have to define a dead zone to prevent flickering
                    if (thisHeight > draggingHeight) {
                        // Dead zone?
                        var deadZone = thisHeight - draggingHeight;
                        var offsetTop = offset(element).top;
                        if (placeholderIndex < thisIndex && pageY < offsetTop) {
                            return;
                        }
                        if (placeholderIndex > thisIndex &&
                            pageY > offsetTop + thisHeight - deadZone) {
                            return;
                        }
                    }
                    if (dragging.oldDisplay === undefined) {
                        dragging.oldDisplay = dragging.style.display;
                    }
                    if (dragging.style.display !== 'none') {
                        dragging.style.display = 'none';
                    }
                    // To avoid flicker, determine where to position the placeholder
                    // based on where the mouse pointer is relative to the elements
                    // vertical center.
                    var placeAfter = false;
                    try {
                        var elementMiddle = offset(element).top + element.offsetHeight / 2;
                        placeAfter = pageY >= elementMiddle;
                    }
                    catch (e) {
                        placeAfter = placeholderIndex < thisIndex;
                    }
                    if (placeAfter) {
                        insertAfter(element, store(sortableElement).placeholder);
                    }
                    else {
                        insertBefore(element, store(sortableElement).placeholder);
                    }
                    // get placeholders from all stores & remove all but current one
                    Array.from(stores.values())
                        .filter(function (data) { return data.placeholder !== undefined; })
                        .forEach(function (data) {
                        if (data.placeholder !== store(sortableElement).placeholder) {
                            data.placeholder.remove();
                        }
                    });
                }
                else {
                    // get all placeholders from store
                    var placeholders = Array.from(stores.values())
                        .filter(function (data) { return data.placeholder !== undefined; })
                        .map(function (data) {
                        return data.placeholder;
                    });
                    // check if element is not in placeholders
                    if (placeholders.indexOf(element) === -1 && sortableElement === element && !_filter(element.children, options.items).length) {
                        placeholders.forEach(function (element) { return element.remove(); });
                        element.appendChild(store(sortableElement).placeholder);
                    }
                }
            }, options.debounce);
            // Handle dragover and dragenter events on draggable items
            var onDragOverEnter = function (e) {
                var element = e.target;
                var sortableElement = element.isSortable === true ? element : findSortable(element);
                element = findDragElement(sortableElement, element);
                if (!dragging || !_listsConnected(sortableElement, dragging.parentElement) || addData(sortableElement, '_disabled') === 'true') {
                    return;
                }
                var options = addData(sortableElement, 'opts');
                if (parseInt(options.maxItems) && _filter(sortableElement.children, addData(sortableElement, 'items')).length >= parseInt(options.maxItems) && dragging.parentElement !== sortableElement) {
                    return;
                }
                e.preventDefault();
                e.stopPropagation();
                e.dataTransfer.dropEffect = store(sortableElement).getConfig('copy') === true ? 'copy' : 'move';
                debouncedDragOverEnter(sortableElement, element, e.pageY);
            };
            addEventListener(listItems.concat(sortableElement), 'dragover', onDragOverEnter);
            addEventListener(listItems.concat(sortableElement), 'dragenter', onDragOverEnter);
        });
        return sortableElements;
    }
    sortable.destroy = function (sortableElement) {
        _destroySortable(sortableElement);
    };
    sortable.enable = function (sortableElement) {
        _enableSortable(sortableElement);
    };
    sortable.disable = function (sortableElement) {
        _disableSortable(sortableElement);
    };

    return sortable;

}());
