Sortable.js

/**!
 * Sortable 1.15.6
 * @author	RubaXa   <trash@rubaxa.org>
 * @author	owenm    <owen23355@gmail.com>
 * @license MIT
 */
(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
  typeof define === 'function' && define.amd ? define(factory) :
  (global = global || self, global.Sortable = factory());
}(this, (function () { 'use strict';

  function ownKeys(object, enumerableOnly) {
    var keys = Object.keys(object);
    if (Object.getOwnPropertySymbols) {
      var symbols = Object.getOwnPropertySymbols(object);
      if (enumerableOnly) {
        symbols = symbols.filter(function (sym) {
          return Object.getOwnPropertyDescriptor(object, sym).enumerable;
        });
      }
      keys.push.apply(keys, symbols);
    }
    return keys;
  }
  function _objectSpread2(target) {
    for (var i = 1; i < arguments.length; i++) {
      var source = arguments[i] != null ? arguments[i] : {};
      if (i % 2) {
        ownKeys(Object(source), true).forEach(function (key) {
          _defineProperty(target, key, source[key]);
        });
      } else if (Object.getOwnPropertyDescriptors) {
        Object.defineProperties(target, Object.getOwnPropertyDescriptors(source));
      } else {
        ownKeys(Object(source)).forEach(function (key) {
          Object.defineProperty(target, key, Object.getOwnPropertyDescriptor(source, key));
        });
      }
    }
    return target;
  }
  function _typeof(obj) {
    "@babel/helpers - typeof";

    if (typeof Symbol === "function" && typeof Symbol.iterator === "symbol") {
      _typeof = function (obj) {
        return typeof obj;
      };
    } else {
      _typeof = function (obj) {
        return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj;
      };
    }
    return _typeof(obj);
  }
  function _defineProperty(obj, key, value) {
    if (key in obj) {
      Object.defineProperty(obj, key, {
        value: value,
        enumerable: true,
        configurable: true,
        writable: true
      });
    } else {
      obj[key] = value;
    }
    return obj;
  }
  function _extends() {
    _extends = Object.assign || function (target) {
      for (var i = 1; i < arguments.length; i++) {
        var source = arguments[i];
        for (var key in source) {
          if (Object.prototype.hasOwnProperty.call(source, key)) {
            target[key] = source[key];
          }
        }
      }
      return target;
    };
    return _extends.apply(this, arguments);
  }
  function _objectWithoutPropertiesLoose(source, excluded) {
    if (source == null) return {};
    var target = {};
    var sourceKeys = Object.keys(source);
    var key, i;
    for (i = 0; i < sourceKeys.length; i++) {
      key = sourceKeys[i];
      if (excluded.indexOf(key) >= 0) continue;
      target[key] = source[key];
    }
    return target;
  }
  function _objectWithoutProperties(source, excluded) {
    if (source == null) return {};
    var target = _objectWithoutPropertiesLoose(source, excluded);
    var key, i;
    if (Object.getOwnPropertySymbols) {
      var sourceSymbolKeys = Object.getOwnPropertySymbols(source);
      for (i = 0; i < sourceSymbolKeys.length; i++) {
        key = sourceSymbolKeys[i];
        if (excluded.indexOf(key) >= 0) continue;
        if (!Object.prototype.propertyIsEnumerable.call(source, key)) continue;
        target[key] = source[key];
      }
    }
    return target;
  }
  function _toConsumableArray(arr) {
    return _arrayWithoutHoles(arr) || _iterableToArray(arr) || _unsupportedIterableToArray(arr) || _nonIterableSpread();
  }
  function _arrayWithoutHoles(arr) {
    if (Array.isArray(arr)) return _arrayLikeToArray(arr);
  }
  function _iterableToArray(iter) {
    if (typeof Symbol !== "undefined" && iter[Symbol.iterator] != null || iter["@@iterator"] != null) return Array.from(iter);
  }
  function _unsupportedIterableToArray(o, minLen) {
    if (!o) return;
    if (typeof o === "string") return _arrayLikeToArray(o, minLen);
    var n = Object.prototype.toString.call(o).slice(8, -1);
    if (n === "Object" && o.constructor) n = o.constructor.name;
    if (n === "Map" || n === "Set") return Array.from(o);
    if (n === "Arguments" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen);
  }
  function _arrayLikeToArray(arr, len) {
    if (len == null || len > arr.length) len = arr.length;
    for (var i = 0, arr2 = new Array(len); i < len; i++) arr2[i] = arr[i];
    return arr2;
  }
  function _nonIterableSpread() {
    throw new TypeError("Invalid attempt to spread non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method.");
  }

  var version = "1.15.6";

  function userAgent(pattern) {
    if (typeof window !== 'undefined' && window.navigator) {
      return !! /*@__PURE__*/navigator.userAgent.match(pattern);
    }
  }
  var IE11OrLess = userAgent(/(?:Trident.*rv[ :]?11\.|msie|iemobile|Windows Phone)/i);
  var Edge = userAgent(/Edge/i);
  var FireFox = userAgent(/firefox/i);
  var Safari = userAgent(/safari/i) && !userAgent(/chrome/i) && !userAgent(/android/i);
  var IOS = userAgent(/iP(ad|od|hone)/i);
  var ChromeForAndroid = userAgent(/chrome/i) && userAgent(/android/i);

  var captureMode = {
    capture: false,
    passive: false
  };
  function on(el, event, fn) {
    el.addEventListener(event, fn, !IE11OrLess && captureMode);
  }
  function off(el, event, fn) {
    el.removeEventListener(event, fn, !IE11OrLess && captureMode);
  }
  function matches( /**HTMLElement*/el, /**String*/selector) {
    if (!selector) return;
    selector[0] === '>' && (selector = selector.substring(1));
    if (el) {
      try {
        if (el.matches) {
          return el.matches(selector);
        } else if (el.msMatchesSelector) {
          return el.msMatchesSelector(selector);
        } else if (el.webkitMatchesSelector) {
          return el.webkitMatchesSelector(selector);
        }
      } catch (_) {
        return false;
      }
    }
    return false;
  }
  function getParentOrHost(el) {
    return el.host && el !== document && el.host.nodeType ? el.host : el.parentNode;
  }
  function closest( /**HTMLElement*/el, /**String*/selector, /**HTMLElement*/ctx, includeCTX) {
    if (el) {
      ctx = ctx || document;
      do {
        if (selector != null && (selector[0] === '>' ? el.parentNode === ctx && matches(el, selector) : matches(el, selector)) || includeCTX && el === ctx) {
          return el;
        }
        if (el === ctx) break;
        /* jshint boss:true */
      } while (el = getParentOrHost(el));
    }
    return null;
  }
  var R_SPACE = /\s+/g;
  function toggleClass(el, name, state) {
    if (el && name) {
      if (el.classList) {
        el.classList[state ? 'add' : 'remove'](name);
      } else {
        var className = (' ' + el.className + ' ').replace(R_SPACE, ' ').replace(' ' + name + ' ', ' ');
        el.className = (className + (state ? ' ' + name : '')).replace(R_SPACE, ' ');
      }
    }
  }
  function css(el, prop, val) {
    var style = el && el.style;
    if (style) {
      if (val === void 0) {
        if (document.defaultView && document.defaultView.getComputedStyle) {
          val = document.defaultView.getComputedStyle(el, '');
        } else if (el.currentStyle) {
          val = el.currentStyle;
        }
        return prop === void 0 ? val : val[prop];
      } else {
        if (!(prop in style) && prop.indexOf('webkit') === -1) {
          prop = '-webkit-' + prop;
        }
        style[prop] = val + (typeof val === 'string' ? '' : 'px');
      }
    }
  }
  function matrix(el, selfOnly) {
    var appliedTransforms = '';
    if (typeof el === 'string') {
      appliedTransforms = el;
    } else {
      do {
        var transform = css(el, 'transform');
        if (transform && transform !== 'none') {
          appliedTransforms = transform + ' ' + appliedTransforms;
        }
        /* jshint boss:true */
      } while (!selfOnly && (el = el.parentNode));
    }
    var matrixFn = window.DOMMatrix || window.WebKitCSSMatrix || window.CSSMatrix || window.MSCSSMatrix;
    /*jshint -W056 */
    return matrixFn && new matrixFn(appliedTransforms);
  }
  function find(ctx, tagName, iterator) {
    if (ctx) {
      var list = ctx.getElementsByTagName(tagName),
        i = 0,
        n = list.length;
      if (iterator) {
        for (; i < n; i++) {
          iterator(list[i], i);
        }
      }
      return list;
    }
    return [];
  }
  function getWindowScrollingElement() {
    var scrollingElement = document.scrollingElement;
    if (scrollingElement) {
      return scrollingElement;
    } else {
      return document.documentElement;
    }
  }

  /**
   * Returns the "bounding client rect" of given element
   * @param  {HTMLElement} el                       The element whose boundingClientRect is wanted
   * @param  {[Boolean]} relativeToContainingBlock  Whether the rect should be relative to the containing block of (including) the container
   * @param  {[Boolean]} relativeToNonStaticParent  Whether the rect should be relative to the relative parent of (including) the contaienr
   * @param  {[Boolean]} undoScale                  Whether the container's scale() should be undone
   * @param  {[HTMLElement]} container              The parent the element will be placed in
   * @return {Object}                               The boundingClientRect of el, with specified adjustments
   */
  function getRect(el, relativeToContainingBlock, relativeToNonStaticParent, undoScale, container) {
    if (!el.getBoundingClientRect && el !== window) return;
    var elRect, top, left, bottom, right, height, width;
    if (el !== window && el.parentNode && el !== getWindowScrollingElement()) {
      elRect = el.getBoundingClientRect();
      top = elRect.top;
      left = elRect.left;
      bottom = elRect.bottom;
      right = elRect.right;
      height = elRect.height;
      width = elRect.width;
    } else {
      top = 0;
      left = 0;
      bottom = window.innerHeight;
      right = window.innerWidth;
      height = window.innerHeight;
      width = window.innerWidth;
    }
    if ((relativeToContainingBlock || relativeToNonStaticParent) && el !== window) {
      // Adjust for translate()
      container = container || el.parentNode;

      // solves #1123 (see: https://stackoverflow.com/a/37953806/6088312)
      // Not needed on <= IE11
      if (!IE11OrLess) {
        do {
          if (container && container.getBoundingClientRect && (css(container, 'transform') !== 'none' || relativeToNonStaticParent && css(container, 'position') !== 'static')) {
            var containerRect = container.getBoundingClientRect();

            // Set relative to edges of padding box of container
            top -= containerRect.top + parseInt(css(container, 'border-top-width'));
            left -= containerRect.left + parseInt(css(container, 'border-left-width'));
            bottom = top + elRect.height;
            right = left + elRect.width;
            break;
          }
          /* jshint boss:true */
        } while (container = container.parentNode);
      }
    }
    if (undoScale && el !== window) {
      // Adjust for scale()
      var elMatrix = matrix(container || el),
        scaleX = elMatrix && elMatrix.a,
        scaleY = elMatrix && elMatrix.d;
      if (elMatrix) {
        top /= scaleY;
        left /= scaleX;
        width /= scaleX;
        height /= scaleY;
        bottom = top + height;
        right = left + width;
      }
    }
    return {
      top: top,
      left: left,
      bottom: bottom,
      right: right,
      width: width,
      height: height
    };
  }

  /**
   * Checks if a side of an element is scrolled past a side of its parents
   * @param  {HTMLElement}  el           The element who's side being scrolled out of view is in question
   * @param  {String}       elSide       Side of the element in question ('top', 'left', 'right', 'bottom')
   * @param  {String}       parentSide   Side of the parent in question ('top', 'left', 'right', 'bottom')
   * @return {HTMLElement}               The parent scroll element that the el's side is scrolled past, or null if there is no such element
   */
  function isScrolledPast(el, elSide, parentSide) {
    var parent = getParentAutoScrollElement(el, true),
      elSideVal = getRect(el)[elSide];

    /* jshint boss:true */
    while (parent) {
      var parentSideVal = getRect(parent)[parentSide],
        visible = void 0;
      if (parentSide === 'top' || parentSide === 'left') {
        visible = elSideVal >= parentSideVal;
      } else {
        visible = elSideVal <= parentSideVal;
      }
      if (!visible) return parent;
      if (parent === getWindowScrollingElement()) break;
      parent = getParentAutoScrollElement(parent, false);
    }
    return false;
  }

  /**
   * Gets nth child of el, ignoring hidden children, sortable's elements (does not ignore clone if it's visible)
   * and non-draggable elements
   * @param  {HTMLElement} el       The parent element
   * @param  {Number} childNum      The index of the child
   * @param  {Object} options       Parent Sortable's options
   * @return {HTMLElement}          The child at index childNum, or null if not found
   */
  function getChild(el, childNum, options, includeDragEl) {
    var currentChild = 0,
      i = 0,
      children = el.children;
    while (i < children.length) {
      if (children[i].style.display !== 'none' && children[i] !== Sortable.ghost && (includeDragEl || children[i] !== Sortable.dragged) && closest(children[i], options.draggable, el, false)) {
        if (currentChild === childNum) {
          return children[i];
        }
        currentChild++;
      }
      i++;
    }
    return null;
  }

  /**
   * Gets the last child in the el, ignoring ghostEl or invisible elements (clones)
   * @param  {HTMLElement} el       Parent element
   * @param  {selector} selector    Any other elements that should be ignored
   * @return {HTMLElement}          The last child, ignoring ghostEl
   */
  function lastChild(el, selector) {
    var last = el.lastElementChild;
    while (last && (last === Sortable.ghost || css(last, 'display') === 'none' || selector && !matches(last, selector))) {
      last = last.previousElementSibling;
    }
    return last || null;
  }

  /**
   * Returns the index of an element within its parent for a selected set of
   * elements
   * @param  {HTMLElement} el
   * @param  {selector} selector
   * @return {number}
   */
  function index(el, selector) {
    var index = 0;
    if (!el || !el.parentNode) {
      return -1;
    }

    /* jshint boss:true */
    while (el = el.previousElementSibling) {
      if (el.nodeName.toUpperCase() !== 'TEMPLATE' && el !== Sortable.clone && (!selector || matches(el, selector))) {
        index++;
      }
    }
    return index;
  }

  /**
   * Returns the scroll offset of the given element, added with all the scroll offsets of parent elements.
   * The value is returned in real pixels.
   * @param  {HTMLElement} el
   * @return {Array}             Offsets in the format of [left, top]
   */
  function getRelativeScrollOffset(el) {
    var offsetLeft = 0,
      offsetTop = 0,
      winScroller = getWindowScrollingElement();
    if (el) {
      do {
        var elMatrix = matrix(el),
          scaleX = elMatrix.a,
          scaleY = elMatrix.d;
        offsetLeft += el.scrollLeft * scaleX;
        offsetTop += el.scrollTop * scaleY;
      } while (el !== winScroller && (el = el.parentNode));
    }
    return [offsetLeft, offsetTop];
  }

  /**
   * Returns the index of the object within the given array
   * @param  {Array} arr   Array that may or may not hold the object
   * @param  {Object} obj  An object that has a key-value pair unique to and identical to a key-value pair in the object you want to find
   * @return {Number}      The index of the object in the array, or -1
   */
  function indexOfObject(arr, obj) {
    for (var i in arr) {
      if (!arr.hasOwnProperty(i)) continue;
      for (var key in obj) {
        if (obj.hasOwnProperty(key) && obj[key] === arr[i][key]) return Number(i);
      }
    }
    return -1;
  }
  function getParentAutoScrollElement(el, includeSelf) {
    // skip to window
    if (!el || !el.getBoundingClientRect) return getWindowScrollingElement();
    var elem = el;
    var gotSelf = false;
    do {
      // we don't need to get elem css if it isn't even overflowing in the first place (performance)
      if (elem.clientWidth < elem.scrollWidth || elem.clientHeight < elem.scrollHeight) {
        var elemCSS = css(elem);
        if (elem.clientWidth < elem.scrollWidth && (elemCSS.overflowX == 'auto' || elemCSS.overflowX == 'scroll') || elem.clientHeight < elem.scrollHeight && (elemCSS.overflowY == 'auto' || elemCSS.overflowY == 'scroll')) {
          if (!elem.getBoundingClientRect || elem === document.body) return getWindowScrollingElement();
          if (gotSelf || includeSelf) return elem;
          gotSelf = true;
        }
      }
      /* jshint boss:true */
    } while (elem = elem.parentNode);
    return getWindowScrollingElement();
  }
  function extend(dst, src) {
    if (dst && src) {
      for (var key in src) {
        if (src.hasOwnProperty(key)) {
          dst[key] = src[key];
        }
      }
    }
    return dst;
  }
  function isRectEqual(rect1, rect2) {
    return Math.round(rect1.top) === Math.round(rect2.top) && Math.round(rect1.left) === Math.round(rect2.left) && Math.round(rect1.height) === Math.round(rect2.height) && Math.round(rect1.width) === Math.round(rect2.width);
  }
  var _throttleTimeout;
  function throttle(callback, ms) {
    return function () {
      if (!_throttleTimeout) {
        var args = arguments,
          _this = this;
        if (args.length === 1) {
          callback.call(_this, args[0]);
        } else {
          callback.apply(_this, args);
        }
        _throttleTimeout = setTimeout(function () {
          _throttleTimeout = void 0;
        }, ms);
      }
    };
  }
  function cancelThrottle() {
    clearTimeout(_throttleTimeout);
    _throttleTimeout = void 0;
  }
  function scrollBy(el, x, y) {
    el.scrollLeft += x;
    el.scrollTop += y;
  }
  function clone(el) {
    var Polymer = window.Polymer;
    var $ = window.jQuery || window.Zepto;
    if (Polymer && Polymer.dom) {
      return Polymer.dom(el).cloneNode(true);
    } else if ($) {
      return $(el).clone(true)[0];
    } else {
      return el.cloneNode(true);
    }
  }
  function setRect(el, rect) {
    css(el, 'position', 'absolute');
    css(el, 'top', rect.top);
    css(el, 'left', rect.left);
    css(el, 'width', rect.width);
    css(el, 'height', rect.height);
  }
  function unsetRect(el) {
    css(el, 'position', '');
    css(el, 'top', '');
    css(el, 'left', '');
    css(el, 'width', '');
    css(el, 'height', '');
  }
  function getChildContainingRectFromElement(container, options, ghostEl) {
    var rect = {};
    Array.from(container.children).forEach(function (child) {
      var _rect$left, _rect$top, _rect$right, _rect$bottom;
      if (!closest(child, options.draggable, container, false) || child.animated || child === ghostEl) return;
      var childRect = getRect(child);
      rect.left = Math.min((_rect$left = rect.left) !== null && _rect$left !== void 0 ? _rect$left : Infinity, childRect.left);
      rect.top = Math.min((_rect$top = rect.top) !== null && _rect$top !== void 0 ? _rect$top : Infinity, childRect.top);
      rect.right = Math.max((_rect$right = rect.right) !== null && _rect$right !== void 0 ? _rect$right : -Infinity, childRect.right);
      rect.bottom = Math.max((_rect$bottom = rect.bottom) !== null && _rect$bottom !== void 0 ? _rect$bottom : -Infinity, childRect.bottom);
    });
    rect.width = rect.right - rect.left;
    rect.height = rect.bottom - rect.top;
    rect.x = rect.left;
    rect.y = rect.top;
    return rect;
  }
  var expando = 'Sortable' + new Date().getTime();

  function AnimationStateManager() {
    var animationStates = [],
      animationCallbackId;
    return {
      captureAnimationState: function captureAnimationState() {
        animationStates = [];
        if (!this.options.animation) return;
        var children = [].slice.call(this.el.children);
        children.forEach(function (child) {
          if (css(child, 'display') === 'none' || child === Sortable.ghost) return;
          animationStates.push({
            target: child,
            rect: getRect(child)
          });
          var fromRect = _objectSpread2({}, animationStates[animationStates.length - 1].rect);

          // If animating: compensate for current animation
          if (child.thisAnimationDuration) {
            var childMatrix = matrix(child, true);
            if (childMatrix) {
              fromRect.top -= childMatrix.f;
              fromRect.left -= childMatrix.e;
            }
          }
          child.fromRect = fromRect;
        });
      },
      addAnimationState: function addAnimationState(state) {
        animationStates.push(state);
      },
      removeAnimationState: function removeAnimationState(target) {
        animationStates.splice(indexOfObject(animationStates, {
          target: target
        }), 1);
      },
      animateAll: function animateAll(callback) {
        var _this = this;
        if (!this.options.animation) {
          clearTimeout(animationCallbackId);
          if (typeof callback === 'function') callback();
          return;
        }
        var animating = false,
          animationTime = 0;
        animationStates.forEach(function (state) {
          var time = 0,
            target = state.target,
            fromRect = target.fromRect,
            toRect = getRect(target),
            prevFromRect = target.prevFromRect,
            prevToRect = target.prevToRect,
            animatingRect = state.rect,
            targetMatrix = matrix(target, true);
          if (targetMatrix) {
            // Compensate for current animation
            toRect.top -= targetMatrix.f;
            toRect.left -= targetMatrix.e;
          }
          target.toRect = toRect;
          if (target.thisAnimationDuration) {
            // Could also check if animatingRect is between fromRect and toRect
            if (isRectEqual(prevFromRect, toRect) && !isRectEqual(fromRect, toRect) &&
            // Make sure animatingRect is on line between toRect & fromRect
            (animatingRect.top - toRect.top) / (animatingRect.left - toRect.left) === (fromRect.top - toRect.top) / (fromRect.left - toRect.left)) {
              // If returning to same place as started from animation and on same axis
              time = calculateRealTime(animatingRect, prevFromRect, prevToRect, _this.options);
            }
          }

          // if fromRect != toRect: animate
          if (!isRectEqual(toRect, fromRect)) {
            target.prevFromRect = fromRect;
            target.prevToRect = toRect;
            if (!time) {
              time = _this.options.animation;
            }
            _this.animate(target, animatingRect, toRect, time);
          }
          if (time) {
            animating = true;
            animationTime = Math.max(animationTime, time);
            clearTimeout(target.animationResetTimer);
            target.animationResetTimer = setTimeout(function () {
              target.animationTime = 0;
              target.prevFromRect = null;
              target.fromRect = null;
              target.prevToRect = null;
              target.thisAnimationDuration = null;
            }, time);
            target.thisAnimationDuration = time;
          }
        });
        clearTimeout(animationCallbackId);
        if (!animating) {
          if (typeof callback === 'function') callback();
        } else {
          animationCallbackId = setTimeout(function () {
            if (typeof callback === 'function') callback();
          }, animationTime);
        }
        animationStates = [];
      },
      animate: function animate(target, currentRect, toRect, duration) {
        if (duration) {
          css(target, 'transition', '');
          css(target, 'transform', '');
          var elMatrix = matrix(this.el),
            scaleX = elMatrix && elMatrix.a,
            scaleY = elMatrix && elMatrix.d,
            translateX = (currentRect.left - toRect.left) / (scaleX || 1),
            translateY = (currentRect.top - toRect.top) / (scaleY || 1);
          target.animatingX = !!translateX;
          target.animatingY = !!translateY;
          css(target, 'transform', 'translate3d(' + translateX + 'px,' + translateY + 'px,0)');
          this.forRepaintDummy = repaint(target); // repaint

          css(target, 'transition', 'transform ' + duration + 'ms' + (this.options.easing ? ' ' + this.options.easing : ''));
          css(target, 'transform', 'translate3d(0,0,0)');
          typeof target.animated === 'number' && clearTimeout(target.animated);
          target.animated = setTimeout(function () {
            css(target, 'transition', '');
            css(target, 'transform', '');
            target.animated = false;
            target.animatingX = false;
            target.animatingY = false;
          }, duration);
        }
      }
    };
  }
  function repaint(target) {
    return target.offsetWidth;
  }
  function calculateRealTime(animatingRect, fromRect, toRect, options) {
    return Math.sqrt(Math.pow(fromRect.top - animatingRect.top, 2) + Math.pow(fromRect.left - animatingRect.left, 2)) / Math.sqrt(Math.pow(fromRect.top - toRect.top, 2) + Math.pow(fromRect.left - toRect.left, 2)) * options.animation;
  }

  var plugins = [];
  var defaults = {
    initializeByDefault: true
  };
  var PluginManager = {
    mount: function mount(plugin) {
      // Set default static properties
      for (var option in defaults) {
        if (defaults.hasOwnProperty(option) && !(option in plugin)) {
          plugin[option] = defaults[option];
        }
      }
      plugins.forEach(function (p) {
        if (p.pluginName === plugin.pluginName) {
          throw "Sortable: Cannot mount plugin ".concat(plugin.pluginName, " more than once");
        }
      });
      plugins.push(plugin);
    },
    pluginEvent: function pluginEvent(eventName, sortable, evt) {
      var _this = this;
      this.eventCanceled = false;
      evt.cancel = function () {
        _this.eventCanceled = true;
      };
      var eventNameGlobal = eventName + 'Global';
      plugins.forEach(function (plugin) {
        if (!sortable[plugin.pluginName]) return;
        // Fire global events if it exists in this sortable
        if (sortable[plugin.pluginName][eventNameGlobal]) {
          sortable[plugin.pluginName][eventNameGlobal](_objectSpread2({
            sortable: sortable
          }, evt));
        }

        // Only fire plugin event if plugin is enabled in this sortable,
        // and plugin has event defined
        if (sortable.options[plugin.pluginName] && sortable[plugin.pluginName][eventName]) {
          sortable[plugin.pluginName][eventName](_objectSpread2({
            sortable: sortable
          }, evt));
        }
      });
    },
    initializePlugins: function initializePlugins(sortable, el, defaults, options) {
      plugins.forEach(function (plugin) {
        var pluginName = plugin.pluginName;
        if (!sortable.options[pluginName] && !plugin.initializeByDefault) return;
        var initialized = new plugin(sortable, el, sortable.options);
        initialized.sortable = sortable;
        initialized.options = sortable.options;
        sortable[pluginName] = initialized;

        // Add default options from plugin
        _extends(defaults, initialized.defaults);
      });
      for (var option in sortable.options) {
        if (!sortable.options.hasOwnProperty(option)) continue;
        var modified = this.modifyOption(sortable, option, sortable.options[option]);
        if (typeof modified !== 'undefined') {
          sortable.options[option] = modified;
        }
      }
    },
    getEventProperties: function getEventProperties(name, sortable) {
      var eventProperties = {};
      plugins.forEach(function (plugin) {
        if (typeof plugin.eventProperties !== 'function') return;
        _extends(eventProperties, plugin.eventProperties.call(sortable[plugin.pluginName], name));
      });
      return eventProperties;
    },
    modifyOption: function modifyOption(sortable, name, value) {
      var modifiedValue;
      plugins.forEach(function (plugin) {
        // Plugin must exist on the Sortable
        if (!sortable[plugin.pluginName]) return;

        // If static option listener exists for this option, call in the context of the Sortable's instance of this plugin
        if (plugin.optionListeners && typeof plugin.optionListeners[name] === 'function') {
          modifiedValue = plugin.optionListeners[name].call(sortable[plugin.pluginName], value);
        }
      });
      return modifiedValue;
    }
  };

  function dispatchEvent(_ref) {
    var sortable = _ref.sortable,
      rootEl = _ref.rootEl,
      name = _ref.name,
      targetEl = _ref.targetEl,
      cloneEl = _ref.cloneEl,
      toEl = _ref.toEl,
      fromEl = _ref.fromEl,
      oldIndex = _ref.oldIndex,
      newIndex = _ref.newIndex,
      oldDraggableIndex = _ref.oldDraggableIndex,
      newDraggableIndex = _ref.newDraggableIndex,
      originalEvent = _ref.originalEvent,
      putSortable = _ref.putSortable,
      extraEventProperties = _ref.extraEventProperties;
    sortable = sortable || rootEl && rootEl[expando];
    if (!sortable) return;
    var evt,
      options = sortable.options,
      onName = 'on' + name.charAt(0).toUpperCase() + name.substr(1);
    // Support for new CustomEvent feature
    if (window.CustomEvent && !IE11OrLess && !Edge) {
      evt = new CustomEvent(name, {
        bubbles: true,
        cancelable: true
      });
    } else {
      evt = document.createEvent('Event');
      evt.initEvent(name, true, true);
    }
    evt.to = toEl || rootEl;
    evt.from = fromEl || rootEl;
    evt.item = targetEl || rootEl;
    evt.clone = cloneEl;
    evt.oldIndex = oldIndex;
    evt.newIndex = newIndex;
    evt.oldDraggableIndex = oldDraggableIndex;
    evt.newDraggableIndex = newDraggableIndex;
    evt.originalEvent = originalEvent;
    evt.pullMode = putSortable ? putSortable.lastPutMode : undefined;
    var allEventProperties = _objectSpread2(_objectSpread2({}, extraEventProperties), PluginManager.getEventProperties(name, sortable));
    for (var option in allEventProperties) {
      evt[option] = allEventProperties[option];
    }
    if (rootEl) {
      rootEl.dispatchEvent(evt);
    }
    if (options[onName]) {
      options[onName].call(sortable, evt);
    }
  }

  var _excluded = ["evt"];
  var pluginEvent = function pluginEvent(eventName, sortable) {
    var _ref = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : {},
      originalEvent = _ref.evt,
      data = _objectWithoutProperties(_ref, _excluded);
    PluginManager.pluginEvent.bind(Sortable)(eventName, sortable, _objectSpread2({
      dragEl: dragEl,
      parentEl: parentEl,
      ghostEl: ghostEl,
      rootEl: rootEl,
      nextEl: nextEl,
      lastDownEl: lastDownEl,
      cloneEl: cloneEl,
      cloneHidden: cloneHidden,
      dragStarted: moved,
      putSortable: putSortable,
      activeSortable: Sortable.active,
      originalEvent: originalEvent,
      oldIndex: oldIndex,
      oldDraggableIndex: oldDraggableIndex,
      newIndex: newIndex,
      newDraggableIndex: newDraggableIndex,
      hideGhostForTarget: _hideGhostForTarget,
      unhideGhostForTarget: _unhideGhostForTarget,
      cloneNowHidden: function cloneNowHidden() {
        cloneHidden = true;
      },
      cloneNowShown: function cloneNowShown() {
        cloneHidden = false;
      },
      dispatchSortableEvent: function dispatchSortableEvent(name) {
        _dispatchEvent({
          sortable: sortable,
          name: name,
          originalEvent: originalEvent
        });
      }
    }, data));
  };
  function _dispatchEvent(info) {
    dispatchEvent(_objectSpread2({
      putSortable: putSortable,
      cloneEl: cloneEl,
      targetEl: dragEl,
      rootEl: rootEl,
      oldIndex: oldIndex,
      oldDraggableIndex: oldDraggableIndex,
      newIndex: newIndex,
      newDraggableIndex: newDraggableIndex
    }, info));
  }
  var dragEl,
    parentEl,
    ghostEl,
    rootEl,
    nextEl,
    lastDownEl,
    cloneEl,
    cloneHidden,
    oldIndex,
    newIndex,
    oldDraggableIndex,
    newDraggableIndex,
    activeGroup,
    putSortable,
    awaitingDragStarted = false,
    ignoreNextClick = false,
    sortables = [],
    tapEvt,
    touchEvt,
    lastDx,
    lastDy,
    tapDistanceLeft,
    tapDistanceTop,
    moved,
    lastTarget,
    lastDirection,
    pastFirstInvertThresh = false,
    isCircumstantialInvert = false,
    targetMoveDistance,
    // For positioning ghost absolutely
    ghostRelativeParent,
    ghostRelativeParentInitialScroll = [],
    // (left, top)

    _silent = false,
    savedInputChecked = [];

  /** @const */
  var documentExists = typeof document !== 'undefined',
    PositionGhostAbsolutely = IOS,
    CSSFloatProperty = Edge || IE11OrLess ? 'cssFloat' : 'float',
    // This will not pass for IE9, because IE9 DnD only works on anchors
    supportDraggable = documentExists && !ChromeForAndroid && !IOS && 'draggable' in document.createElement('div'),
    supportCssPointerEvents = function () {
      if (!documentExists) return;
      // false when <= IE11
      if (IE11OrLess) {
        return false;
      }
      var el = document.createElement('x');
      el.style.cssText = 'pointer-events:auto';
      return el.style.pointerEvents === 'auto';
    }(),
    _detectDirection = function _detectDirection(el, options) {
      var elCSS = css(el),
        elWidth = parseInt(elCSS.width) - parseInt(elCSS.paddingLeft) - parseInt(elCSS.paddingRight) - parseInt(elCSS.borderLeftWidth) - parseInt(elCSS.borderRightWidth),
        child1 = getChild(el, 0, options),
        child2 = getChild(el, 1, options),
        firstChildCSS = child1 && css(child1),
        secondChildCSS = child2 && css(child2),
        firstChildWidth = firstChildCSS && parseInt(firstChildCSS.marginLeft) + parseInt(firstChildCSS.marginRight) + getRect(child1).width,
        secondChildWidth = secondChildCSS && parseInt(secondChildCSS.marginLeft) + parseInt(secondChildCSS.marginRight) + getRect(child2).width;
      if (elCSS.display === 'flex') {
        return elCSS.flexDirection === 'column' || elCSS.flexDirection === 'column-reverse' ? 'vertical' : 'horizontal';
      }
      if (elCSS.display === 'grid') {
        return elCSS.gridTemplateColumns.split(' ').length <= 1 ? 'vertical' : 'horizontal';
      }
      if (child1 && firstChildCSS["float"] && firstChildCSS["float"] !== 'none') {
        var touchingSideChild2 = firstChildCSS["float"] === 'left' ? 'left' : 'right';
        return child2 && (secondChildCSS.clear === 'both' || secondChildCSS.clear === touchingSideChild2) ? 'vertical' : 'horizontal';
      }
      return child1 && (firstChildCSS.display === 'block' || firstChildCSS.display === 'flex' || firstChildCSS.display === 'table' || firstChildCSS.display === 'grid' || firstChildWidth >= elWidth && elCSS[CSSFloatProperty] === 'none' || child2 && elCSS[CSSFloatProperty] === 'none' && firstChildWidth + secondChildWidth > elWidth) ? 'vertical' : 'horizontal';
    },
    _dragElInRowColumn = function _dragElInRowColumn(dragRect, targetRect, vertical) {
      var dragElS1Opp = vertical ? dragRect.left : dragRect.top,
        dragElS2Opp = vertical ? dragRect.right : dragRect.bottom,
        dragElOppLength = vertical ? dragRect.width : dragRect.height,
        targetS1Opp = vertical ? targetRect.left : targetRect.top,
        targetS2Opp = vertical ? targetRect.right : targetRect.bottom,
        targetOppLength = vertical ? targetRect.width : targetRect.height;
      return dragElS1Opp === targetS1Opp || dragElS2Opp === targetS2Opp || dragElS1Opp + dragElOppLength / 2 === targetS1Opp + targetOppLength / 2;
    },
    /**
     * Detects first nearest empty sortable to X and Y position using emptyInsertThreshold.
     * @param  {Number} x      X position
     * @param  {Number} y      Y position
     * @return {HTMLElement}   Element of the first found nearest Sortable
     */
    _detectNearestEmptySortable = function _detectNearestEmptySortable(x, y) {
      var ret;
      sortables.some(function (sortable) {
        var threshold = sortable[expando].options.emptyInsertThreshold;
        if (!threshold || lastChild(sortable)) return;
        var rect = getRect(sortable),
          insideHorizontally = x >= rect.left - threshold && x <= rect.right + threshold,
          insideVertically = y >= rect.top - threshold && y <= rect.bottom + threshold;
        if (insideHorizontally && insideVertically) {
          return ret = sortable;
        }
      });
      return ret;
    },
    _prepareGroup = function _prepareGroup(options) {
      function toFn(value, pull) {
        return function (to, from, dragEl, evt) {
          var sameGroup = to.options.group.name && from.options.group.name && to.options.group.name === from.options.group.name;
          if (value == null && (pull || sameGroup)) {
            // Default pull value
            // Default pull and put value if same group
            return true;
          } else if (value == null || value === false) {
            return false;
          } else if (pull && value === 'clone') {
            return value;
          } else if (typeof value === 'function') {
            return toFn(value(to, from, dragEl, evt), pull)(to, from, dragEl, evt);
          } else {
            var otherGroup = (pull ? to : from).options.group.name;
            return value === true || typeof value === 'string' && value === otherGroup || value.join && value.indexOf(otherGroup) > -1;
          }
        };
      }
      var group = {};
      var originalGroup = options.group;
      if (!originalGroup || _typeof(originalGroup) != 'object') {
        originalGroup = {
          name: originalGroup
        };
      }
      group.name = originalGroup.name;
      group.checkPull = toFn(originalGroup.pull, true);
      group.checkPut = toFn(originalGroup.put);
      group.revertClone = originalGroup.revertClone;
      options.group = group;
    },
    _hideGhostForTarget = function _hideGhostForTarget() {
      if (!supportCssPointerEvents && ghostEl) {
        css(ghostEl, 'display', 'none');
      }
    },
    _unhideGhostForTarget = function _unhideGhostForTarget() {
      if (!supportCssPointerEvents && ghostEl) {
        css(ghostEl, 'display', '');
      }
    };

  // #1184 fix - Prevent click event on fallback if dragged but item not changed position
  if (documentExists && !ChromeForAndroid) {
    document.addEventListener('click', function (evt) {
      if (ignoreNextClick) {
        evt.preventDefault();
        evt.stopPropagation && evt.stopPropagation();
        evt.stopImmediatePropagation && evt.stopImmediatePropagation();
        ignoreNextClick = false;
        return false;
      }
    }, true);
  }
  var nearestEmptyInsertDetectEvent = function nearestEmptyInsertDetectEvent(evt) {
    if (dragEl) {
      evt = evt.touches ? evt.touches[0] : evt;
      var nearest = _detectNearestEmptySortable(evt.clientX, evt.clientY);
      if (nearest) {
        // Create imitation event
        var event = {};
        for (var i in evt) {
          if (evt.hasOwnProperty(i)) {
            event[i] = evt[i];
          }
        }
        event.target = event.rootEl = nearest;
        event.preventDefault = void 0;
        event.stopPropagation = void 0;
        nearest[expando]._onDragOver(event);
      }
    }
  };
  var _checkOutsideTargetEl = function _checkOutsideTargetEl(evt) {
    if (dragEl) {
      dragEl.parentNode[expando]._isOutsideThisEl(evt.target);
    }
  };

  /**
   * @class  Sortable
   * @param  {HTMLElement}  el
   * @param  {Object}       [options]
   */
  function Sortable(el, options) {
    if (!(el && el.nodeType && el.nodeType === 1)) {
      throw "Sortable: `el` must be an HTMLElement, not ".concat({}.toString.call(el));
    }
    this.el = el; // root element
    this.options = options = _extends({}, options);

    // Export instance
    el[expando] = this;
    var defaults = {
      group: null,
      sort: true,
      disabled: false,
      store: null,
      handle: null,
      draggable: /^[uo]l$/i.test(el.nodeName) ? '>li' : '>*',
      swapThreshold: 1,
      // percentage; 0 <= x <= 1
      invertSwap: false,
      // invert always
      invertedSwapThreshold: null,
      // will be set to same as swapThreshold if default
      removeCloneOnHide: true,
      direction: function direction() {
        return _detectDirection(el, this.options);
      },
      ghostClass: 'sortable-ghost',
      chosenClass: 'sortable-chosen',
      dragClass: 'sortable-drag',
      ignore: 'a, img',
      filter: null,
      preventOnFilter: true,
      animation: 0,
      easing: null,
      setData: function setData(dataTransfer, dragEl) {
        dataTransfer.setData('Text', dragEl.textContent);
      },
      dropBubble: false,
      dragoverBubble: false,
      dataIdAttr: 'data-id',
      delay: 0,
      delayOnTouchOnly: false,
      touchStartThreshold: (Number.parseInt ? Number : window).parseInt(window.devicePixelRatio, 10) || 1,
      forceFallback: false,
      fallbackClass: 'sortable-fallback',
      fallbackOnBody: false,
      fallbackTolerance: 0,
      fallbackOffset: {
        x: 0,
        y: 0
      },
      // Disabled on Safari: #1571; Enabled on Safari IOS: #2244
      supportPointer: Sortable.supportPointer !== false && 'PointerEvent' in window && (!Safari || IOS),
      emptyInsertThreshold: 5
    };
    PluginManager.initializePlugins(this, el, defaults);

    // Set default options
    for (var name in defaults) {
      !(name in options) && (options[name] = defaults[name]);
    }
    _prepareGroup(options);

    // Bind all private methods
    for (var fn in this) {
      if (fn.charAt(0) === '_' && typeof this[fn] === 'function') {
        this[fn] = this[fn].bind(this);
      }
    }

    // Setup drag mode
    this.nativeDraggable = options.forceFallback ? false : supportDraggable;
    if (this.nativeDraggable) {
      // Touch start threshold cannot be greater than the native dragstart threshold
      this.options.touchStartThreshold = 1;
    }

    // Bind events
    if (options.supportPointer) {
      on(el, 'pointerdown', this._onTapStart);
    } else {
      on(el, 'mousedown', this._onTapStart);
      on(el, 'touchstart', this._onTapStart);
    }
    if (this.nativeDraggable) {
      on(el, 'dragover', this);
      on(el, 'dragenter', this);
    }
    sortables.push(this.el);

    // Restore sorting
    options.store && options.store.get && this.sort(options.store.get(this) || []);

    // Add animation state manager
    _extends(this, AnimationStateManager());
  }
  Sortable.prototype = /** @lends Sortable.prototype */{
    constructor: Sortable,
    _isOutsideThisEl: function _isOutsideThisEl(target) {
      if (!this.el.contains(target) && target !== this.el) {
        lastTarget = null;
      }
    },
    _getDirection: function _getDirection(evt, target) {
      return typeof this.options.direction === 'function' ? this.options.direction.call(this, evt, target, dragEl) : this.options.direction;
    },
    _onTapStart: function _onTapStart( /** Event|TouchEvent */evt) {
      if (!evt.cancelable) return;
      var _this = this,
        el = this.el,
        options = this.options,
        preventOnFilter = options.preventOnFilter,
        type = evt.type,
        touch = evt.touches && evt.touches[0] || evt.pointerType && evt.pointerType === 'touch' && evt,
        target = (touch || evt).target,
        originalTarget = evt.target.shadowRoot && (evt.path && evt.path[0] || evt.composedPath && evt.composedPath()[0]) || target,
        filter = options.filter;
      _saveInputCheckedState(el);

      // Don't trigger start event when an element is been dragged, otherwise the evt.oldindex always wrong when set option.group.
      if (dragEl) {
        return;
      }
      if (/mousedown|pointerdown/.test(type) && evt.button !== 0 || options.disabled) {
        return; // only left button and enabled
      }

      // cancel dnd if original target is content editable
      if (originalTarget.isContentEditable) {
        return;
      }

      // Safari ignores further event handling after mousedown
      if (!this.nativeDraggable && Safari && target && target.tagName.toUpperCase() === 'SELECT') {
        return;
      }
      target = closest(target, options.draggable, el, false);
      if (target && target.animated) {
        return;
      }
      if (lastDownEl === target) {
        // Ignoring duplicate `down`
        return;
      }

      // Get the index of the dragged element within its parent
      oldIndex = index(target);
      oldDraggableIndex = index(target, options.draggable);

      // Check filter
      if (typeof filter === 'function') {
        if (filter.call(this, evt, target, this)) {
          _dispatchEvent({
            sortable: _this,
            rootEl: originalTarget,
            name: 'filter',
            targetEl: target,
            toEl: el,
            fromEl: el
          });
          pluginEvent('filter', _this, {
            evt: evt
          });
          preventOnFilter && evt.preventDefault();
          return; // cancel dnd
        }
      } else if (filter) {
        filter = filter.split(',').some(function (criteria) {
          criteria = closest(originalTarget, criteria.trim(), el, false);
          if (criteria) {
            _dispatchEvent({
              sortable: _this,
              rootEl: criteria,
              name: 'filter',
              targetEl: target,
              fromEl: el,
              toEl: el
            });
            pluginEvent('filter', _this, {
              evt: evt
            });
            return true;
          }
        });
        if (filter) {
          preventOnFilter && evt.preventDefault();
          return; // cancel dnd
        }
      }
      if (options.handle && !closest(originalTarget, options.handle, el, false)) {
        return;
      }

      // Prepare `dragstart`
      this._prepareDragStart(evt, touch, target);
    },
    _prepareDragStart: function _prepareDragStart( /** Event */evt, /** Touch */touch, /** HTMLElement */target) {
      var _this = this,
        el = _this.el,
        options = _this.options,
        ownerDocument = el.ownerDocument,
        dragStartFn;
      if (target && !dragEl && target.parentNode === el) {
        var dragRect = getRect(target);
        rootEl = el;
        dragEl = target;
        parentEl = dragEl.parentNode;
        nextEl = dragEl.nextSibling;
        lastDownEl = target;
        activeGroup = options.group;
        Sortable.dragged = dragEl;
        tapEvt = {
          target: dragEl,
          clientX: (touch || evt).clientX,
          clientY: (touch || evt).clientY
        };
        tapDistanceLeft = tapEvt.clientX - dragRect.left;
        tapDistanceTop = tapEvt.clientY - dragRect.top;
        this._lastX = (touch || evt).clientX;
        this._lastY = (touch || evt).clientY;
        dragEl.style['will-change'] = 'all';
        dragStartFn = function dragStartFn() {
          pluginEvent('delayEnded', _this, {
            evt: evt
          });
          if (Sortable.eventCanceled) {
            _this._onDrop();
            return;
          }
          // Delayed drag has been triggered
          // we can re-enable the events: touchmove/mousemove
          _this._disableDelayedDragEvents();
          if (!FireFox && _this.nativeDraggable) {
            dragEl.draggable = true;
          }

          // Bind the events: dragstart/dragend
          _this._triggerDragStart(evt, touch);

          // Drag start event
          _dispatchEvent({
            sortable: _this,
            name: 'choose',
            originalEvent: evt
          });

          // Chosen item
          toggleClass(dragEl, options.chosenClass, true);
        };

        // Disable "draggable"
        options.ignore.split(',').forEach(function (criteria) {
          find(dragEl, criteria.trim(), _disableDraggable);
        });
        on(ownerDocument, 'dragover', nearestEmptyInsertDetectEvent);
        on(ownerDocument, 'mousemove', nearestEmptyInsertDetectEvent);
        on(ownerDocument, 'touchmove', nearestEmptyInsertDetectEvent);
        if (options.supportPointer) {
          on(ownerDocument, 'pointerup', _this._onDrop);
          // Native D&D triggers pointercancel
          !this.nativeDraggable && on(ownerDocument, 'pointercancel', _this._onDrop);
        } else {
          on(ownerDocument, 'mouseup', _this._onDrop);
          on(ownerDocument, 'touchend', _this._onDrop);
          on(ownerDocument, 'touchcancel', _this._onDrop);
        }

        // Make dragEl draggable (must be before delay for FireFox)
        if (FireFox && this.nativeDraggable) {
          this.options.touchStartThreshold = 4;
          dragEl.draggable = true;
        }
        pluginEvent('delayStart', this, {
          evt: evt
        });

        // Delay is impossible for native DnD in Edge or IE
        if (options.delay && (!options.delayOnTouchOnly || touch) && (!this.nativeDraggable || !(Edge || IE11OrLess))) {
          if (Sortable.eventCanceled) {
            this._onDrop();
            return;
          }
          // If the user moves the pointer or let go the click or touch
          // before the delay has been reached:
          // disable the delayed drag
          if (options.supportPointer) {
            on(ownerDocument, 'pointerup', _this._disableDelayedDrag);
            on(ownerDocument, 'pointercancel', _this._disableDelayedDrag);
          } else {
            on(ownerDocument, 'mouseup', _this._disableDelayedDrag);
            on(ownerDocument, 'touchend', _this._disableDelayedDrag);
            on(ownerDocument, 'touchcancel', _this._disableDelayedDrag);
          }
          on(ownerDocument, 'mousemove', _this._delayedDragTouchMoveHandler);
          on(ownerDocument, 'touchmove', _this._delayedDragTouchMoveHandler);
          options.supportPointer && on(ownerDocument, 'pointermove', _this._delayedDragTouchMoveHandler);
          _this._dragStartTimer = setTimeout(dragStartFn, options.delay);
        } else {
          dragStartFn();
        }
      }
    },
    _delayedDragTouchMoveHandler: function _delayedDragTouchMoveHandler( /** TouchEvent|PointerEvent **/e) {
      var touch = e.touches ? e.touches[0] : e;
      if (Math.max(Math.abs(touch.clientX - this._lastX), Math.abs(touch.clientY - this._lastY)) >= Math.floor(this.options.touchStartThreshold / (this.nativeDraggable && window.devicePixelRatio || 1))) {
        this._disableDelayedDrag();
      }
    },
    _disableDelayedDrag: function _disableDelayedDrag() {
      dragEl && _disableDraggable(dragEl);
      clearTimeout(this._dragStartTimer);
      this._disableDelayedDragEvents();
    },
    _disableDelayedDragEvents: function _disableDelayedDragEvents() {
      var ownerDocument = this.el.ownerDocument;
      off(ownerDocument, 'mouseup', this._disableDelayedDrag);
      off(ownerDocument, 'touchend', this._disableDelayedDrag);
      off(ownerDocument, 'touchcancel', this._disableDelayedDrag);
      off(ownerDocument, 'pointerup', this._disableDelayedDrag);
      off(ownerDocument, 'pointercancel', this._disableDelayedDrag);
      off(ownerDocument, 'mousemove', this._delayedDragTouchMoveHandler);
      off(ownerDocument, 'touchmove', this._delayedDragTouchMoveHandler);
      off(ownerDocument, 'pointermove', this._delayedDragTouchMoveHandler);
    },
    _triggerDragStart: function _triggerDragStart( /** Event */evt, /** Touch */touch) {
      touch = touch || evt.pointerType == 'touch' && evt;
      if (!this.nativeDraggable || touch) {
        if (this.options.supportPointer) {
          on(document, 'pointermove', this._onTouchMove);
        } else if (touch) {
          on(document, 'touchmove', this._onTouchMove);
        } else {
          on(document, 'mousemove', this._onTouchMove);
        }
      } else {
        on(dragEl, 'dragend', this);
        on(rootEl, 'dragstart', this._onDragStart);
      }
      try {
        if (document.selection) {
          _nextTick(function () {
            document.selection.empty();
          });
        } else {
          window.getSelection().removeAllRanges();
        }
      } catch (err) {}
    },
    _dragStarted: function _dragStarted(fallback, evt) {
      awaitingDragStarted = false;
      if (rootEl && dragEl) {
        pluginEvent('dragStarted', this, {
          evt: evt
        });
        if (this.nativeDraggable) {
          on(document, 'dragover', _checkOutsideTargetEl);
        }
        var options = this.options;

        // Apply effect
        !fallback && toggleClass(dragEl, options.dragClass, false);
        toggleClass(dragEl, options.ghostClass, true);
        Sortable.active = this;
        fallback && this._appendGhost();

        // Drag start event
        _dispatchEvent({
          sortable: this,
          name: 'start',
          originalEvent: evt
        });
      } else {
        this._nulling();
      }
    },
    _emulateDragOver: function _emulateDragOver() {
      if (touchEvt) {
        this._lastX = touchEvt.clientX;
        this._lastY = touchEvt.clientY;
        _hideGhostForTarget();
        var target = document.elementFromPoint(touchEvt.clientX, touchEvt.clientY);
        var parent = target;
        while (target && target.shadowRoot) {
          target = target.shadowRoot.elementFromPoint(touchEvt.clientX, touchEvt.clientY);
          if (target === parent) break;
          parent = target;
        }
        dragEl.parentNode[expando]._isOutsideThisEl(target);
        if (parent) {
          do {
            if (parent[expando]) {
              var inserted = void 0;
              inserted = parent[expando]._onDragOver({
                clientX: touchEvt.clientX,
                clientY: touchEvt.clientY,
                target: target,
                rootEl: parent
              });
              if (inserted && !this.options.dragoverBubble) {
                break;
              }
            }
            target = parent; // store last element
          }
          /* jshint boss:true */ while (parent = getParentOrHost(parent));
        }
        _unhideGhostForTarget();
      }
    },
    _onTouchMove: function _onTouchMove( /**TouchEvent*/evt) {
      if (tapEvt) {
        var options = this.options,
          fallbackTolerance = options.fallbackTolerance,
          fallbackOffset = options.fallbackOffset,
          touch = evt.touches ? evt.touches[0] : evt,
          ghostMatrix = ghostEl && matrix(ghostEl, true),
          scaleX = ghostEl && ghostMatrix && ghostMatrix.a,
          scaleY = ghostEl && ghostMatrix && ghostMatrix.d,
          relativeScrollOffset = PositionGhostAbsolutely && ghostRelativeParent && getRelativeScrollOffset(ghostRelativeParent),
          dx = (touch.clientX - tapEvt.clientX + fallbackOffset.x) / (scaleX || 1) + (relativeScrollOffset ? relativeScrollOffset[0] - ghostRelativeParentInitialScroll[0] : 0) / (scaleX || 1),
          dy = (touch.clientY - tapEvt.clientY + fallbackOffset.y) / (scaleY || 1) + (relativeScrollOffset ? relativeScrollOffset[1] - ghostRelativeParentInitialScroll[1] : 0) / (scaleY || 1);

        // only set the status to dragging, when we are actually dragging
        if (!Sortable.active && !awaitingDragStarted) {
          if (fallbackTolerance && Math.max(Math.abs(touch.clientX - this._lastX), Math.abs(touch.clientY - this._lastY)) < fallbackTolerance) {
            return;
          }
          this._onDragStart(evt, true);
        }
        if (ghostEl) {
          if (ghostMatrix) {
            ghostMatrix.e += dx - (lastDx || 0);
            ghostMatrix.f += dy - (lastDy || 0);
          } else {
            ghostMatrix = {
              a: 1,
              b: 0,
              c: 0,
              d: 1,
              e: dx,
              f: dy
            };
          }
          var cssMatrix = "matrix(".concat(ghostMatrix.a, ",").concat(ghostMatrix.b, ",").concat(ghostMatrix.c, ",").concat(ghostMatrix.d, ",").concat(ghostMatrix.e, ",").concat(ghostMatrix.f, ")");
          css(ghostEl, 'webkitTransform', cssMatrix);
          css(ghostEl, 'mozTransform', cssMatrix);
          css(ghostEl, 'msTransform', cssMatrix);
          css(ghostEl, 'transform', cssMatrix);
          lastDx = dx;
          lastDy = dy;
          touchEvt = touch;
        }
        evt.cancelable && evt.preventDefault();
      }
    },
    _appendGhost: function _appendGhost() {
      // Bug if using scale(): https://stackoverflow.com/questions/2637058
      // Not being adjusted for
      if (!ghostEl) {
        var container = this.options.fallbackOnBody ? document.body : rootEl,
          rect = getRect(dragEl, true, PositionGhostAbsolutely, true, container),
          options = this.options;

        // Position absolutely
        if (PositionGhostAbsolutely) {
          // Get relatively positioned parent
          ghostRelativeParent = container;
          while (css(ghostRelativeParent, 'position') === 'static' && css(ghostRelativeParent, 'transform') === 'none' && ghostRelativeParent !== document) {
            ghostRelativeParent = ghostRelativeParent.parentNode;
          }
          if (ghostRelativeParent !== document.body && ghostRelativeParent !== document.documentElement) {
            if (ghostRelativeParent === document) ghostRelativeParent = getWindowScrollingElement();
            rect.top += ghostRelativeParent.scrollTop;
            rect.left += ghostRelativeParent.scrollLeft;
          } else {
            ghostRelativeParent = getWindowScrollingElement();
          }
          ghostRelativeParentInitialScroll = getRelativeScrollOffset(ghostRelativeParent);
        }
        ghostEl = dragEl.cloneNode(true);
        toggleClass(ghostEl, options.ghostClass, false);
        toggleClass(ghostEl, options.fallbackClass, true);
        toggleClass(ghostEl, options.dragClass, true);
        css(ghostEl, 'transition', '');
        css(ghostEl, 'transform', '');
        css(ghostEl, 'box-sizing', 'border-box');
        css(ghostEl, 'margin', 0);
        css(ghostEl, 'top', rect.top);
        css(ghostEl, 'left', rect.left);
        css(ghostEl, 'width', rect.width);
        css(ghostEl, 'height', rect.height);
        css(ghostEl, 'opacity', '0.8');
        css(ghostEl, 'position', PositionGhostAbsolutely ? 'absolute' : 'fixed');
        css(ghostEl, 'zIndex', '100000');
        css(ghostEl, 'pointerEvents', 'none');
        Sortable.ghost = ghostEl;
        container.appendChild(ghostEl);

        // Set transform-origin
        css(ghostEl, 'transform-origin', tapDistanceLeft / parseInt(ghostEl.style.width) * 100 + '% ' + tapDistanceTop / parseInt(ghostEl.style.height) * 100 + '%');
      }
    },
    _onDragStart: function _onDragStart( /**Event*/evt, /**boolean*/fallback) {
      var _this = this;
      var dataTransfer = evt.dataTransfer;
      var options = _this.options;
      pluginEvent('dragStart', this, {
        evt: evt
      });
      if (Sortable.eventCanceled) {
        this._onDrop();
        return;
      }
      pluginEvent('setupClone', this);
      if (!Sortable.eventCanceled) {
        cloneEl = clone(dragEl);
        cloneEl.removeAttribute("id");
        cloneEl.draggable = false;
        cloneEl.style['will-change'] = '';
        this._hideClone();
        toggleClass(cloneEl, this.options.chosenClass, false);
        Sortable.clone = cloneEl;
      }

      // #1143: IFrame support workaround
      _this.cloneId = _nextTick(function () {
        pluginEvent('clone', _this);
        if (Sortable.eventCanceled) return;
        if (!_this.options.removeCloneOnHide) {
          rootEl.insertBefore(cloneEl, dragEl);
        }
        _this._hideClone();
        _dispatchEvent({
          sortable: _this,
          name: 'clone'
        });
      });
      !fallback && toggleClass(dragEl, options.dragClass, true);

      // Set proper drop events
      if (fallback) {
        ignoreNextClick = true;
        _this._loopId = setInterval(_this._emulateDragOver, 50);
      } else {
        // Undo what was set in _prepareDragStart before drag started
        off(document, 'mouseup', _this._onDrop);
        off(document, 'touchend', _this._onDrop);
        off(document, 'touchcancel', _this._onDrop);
        if (dataTransfer) {
          dataTransfer.effectAllowed = 'move';
          options.setData && options.setData.call(_this, dataTransfer, dragEl);
        }
        on(document, 'drop', _this);

        // #1276 fix:
        css(dragEl, 'transform', 'translateZ(0)');
      }
      awaitingDragStarted = true;
      _this._dragStartId = _nextTick(_this._dragStarted.bind(_this, fallback, evt));
      on(document, 'selectstart', _this);
      moved = true;
      window.getSelection().removeAllRanges();
      if (Safari) {
        css(document.body, 'user-select', 'none');
      }
    },
    // Returns true - if no further action is needed (either inserted or another condition)
    _onDragOver: function _onDragOver( /**Event*/evt) {
      var el = this.el,
        target = evt.target,
        dragRect,
        targetRect,
        revert,
        options = this.options,
        group = options.group,
        activeSortable = Sortable.active,
        isOwner = activeGroup === group,
        canSort = options.sort,
        fromSortable = putSortable || activeSortable,
        vertical,
        _this = this,
        completedFired = false;
      if (_silent) return;
      function dragOverEvent(name, extra) {
        pluginEvent(name, _this, _objectSpread2({
          evt: evt,
          isOwner: isOwner,
          axis: vertical ? 'vertical' : 'horizontal',
          revert: revert,
          dragRect: dragRect,
          targetRect: targetRect,
          canSort: canSort,
          fromSortable: fromSortable,
          target: target,
          completed: completed,
          onMove: function onMove(target, after) {
            return _onMove(rootEl, el, dragEl, dragRect, target, getRect(target), evt, after);
          },
          changed: changed
        }, extra));
      }

      // Capture animation state
      function capture() {
        dragOverEvent('dragOverAnimationCapture');
        _this.captureAnimationState();
        if (_this !== fromSortable) {
          fromSortable.captureAnimationState();
        }
      }

      // Return invocation when dragEl is inserted (or completed)
      function completed(insertion) {
        dragOverEvent('dragOverCompleted', {
          insertion: insertion
        });
        if (insertion) {
          // Clones must be hidden before folding animation to capture dragRectAbsolute properly
          if (isOwner) {
            activeSortable._hideClone();
          } else {
            activeSortable._showClone(_this);
          }
          if (_this !== fromSortable) {
            // Set ghost class to new sortable's ghost class
            toggleClass(dragEl, putSortable ? putSortable.options.ghostClass : activeSortable.options.ghostClass, false);
            toggleClass(dragEl, options.ghostClass, true);
          }
          if (putSortable !== _this && _this !== Sortable.active) {
            putSortable = _this;
          } else if (_this === Sortable.active && putSortable) {
            putSortable = null;
          }

          // Animation
          if (fromSortable === _this) {
            _this._ignoreWhileAnimating = target;
          }
          _this.animateAll(function () {
            dragOverEvent('dragOverAnimationComplete');
            _this._ignoreWhileAnimating = null;
          });
          if (_this !== fromSortable) {
            fromSortable.animateAll();
            fromSortable._ignoreWhileAnimating = null;
          }
        }

        // Null lastTarget if it is not inside a previously swapped element
        if (target === dragEl && !dragEl.animated || target === el && !target.animated) {
          lastTarget = null;
        }

        // no bubbling and not fallback
        if (!options.dragoverBubble && !evt.rootEl && target !== document) {
          dragEl.parentNode[expando]._isOutsideThisEl(evt.target);

          // Do not detect for empty insert if already inserted
          !insertion && nearestEmptyInsertDetectEvent(evt);
        }
        !options.dragoverBubble && evt.stopPropagation && evt.stopPropagation();
        return completedFired = true;
      }

      // Call when dragEl has been inserted
      function changed() {
        newIndex = index(dragEl);
        newDraggableIndex = index(dragEl, options.draggable);
        _dispatchEvent({
          sortable: _this,
          name: 'change',
          toEl: el,
          newIndex: newIndex,
          newDraggableIndex: newDraggableIndex,
          originalEvent: evt
        });
      }
      if (evt.preventDefault !== void 0) {
        evt.cancelable && evt.preventDefault();
      }
      target = closest(target, options.draggable, el, true);
      dragOverEvent('dragOver');
      if (Sortable.eventCanceled) return completedFired;
      if (dragEl.contains(evt.target) || target.animated && target.animatingX && target.animatingY || _this._ignoreWhileAnimating === target) {
        return completed(false);
      }
      ignoreNextClick = false;
      if (activeSortable && !options.disabled && (isOwner ? canSort || (revert = parentEl !== rootEl) // Reverting item into the original list
      : putSortable === this || (this.lastPutMode = activeGroup.checkPull(this, activeSortable, dragEl, evt)) && group.checkPut(this, activeSortable, dragEl, evt))) {
        vertical = this._getDirection(evt, target) === 'vertical';
        dragRect = getRect(dragEl);
        dragOverEvent('dragOverValid');
        if (Sortable.eventCanceled) return completedFired;
        if (revert) {
          parentEl = rootEl; // actualization
          capture();
          this._hideClone();
          dragOverEvent('revert');
          if (!Sortable.eventCanceled) {
            if (nextEl) {
              rootEl.insertBefore(dragEl, nextEl);
            } else {
              rootEl.appendChild(dragEl);
            }
          }
          return completed(true);
        }
        var elLastChild = lastChild(el, options.draggable);
        if (!elLastChild || _ghostIsLast(evt, vertical, this) && !elLastChild.animated) {
          // Insert to end of list

          // If already at end of list: Do not insert
          if (elLastChild === dragEl) {
            return completed(false);
          }

          // if there is a last element, it is the target
          if (elLastChild && el === evt.target) {
            target = elLastChild;
          }
          if (target) {
            targetRect = getRect(target);
          }
          if (_onMove(rootEl, el, dragEl, dragRect, target, targetRect, evt, !!target) !== false) {
            capture();
            if (elLastChild && elLastChild.nextSibling) {
              // the last draggable element is not the last node
              el.insertBefore(dragEl, elLastChild.nextSibling);
            } else {
              el.appendChild(dragEl);
            }
            parentEl = el; // actualization

            changed();
            return completed(true);
          }
        } else if (elLastChild && _ghostIsFirst(evt, vertical, this)) {
          // Insert to start of list
          var firstChild = getChild(el, 0, options, true);
          if (firstChild === dragEl) {
            return completed(false);
          }
          target = firstChild;
          targetRect = getRect(target);
          if (_onMove(rootEl, el, dragEl, dragRect, target, targetRect, evt, false) !== false) {
            capture();
            el.insertBefore(dragEl, firstChild);
            parentEl = el; // actualization

            changed();
            return completed(true);
          }
        } else if (target.parentNode === el) {
          targetRect = getRect(target);
          var direction = 0,
            targetBeforeFirstSwap,
            differentLevel = dragEl.parentNode !== el,
            differentRowCol = !_dragElInRowColumn(dragEl.animated && dragEl.toRect || dragRect, target.animated && target.toRect || targetRect, vertical),
            side1 = vertical ? 'top' : 'left',
            scrolledPastTop = isScrolledPast(target, 'top', 'top') || isScrolledPast(dragEl, 'top', 'top'),
            scrollBefore = scrolledPastTop ? scrolledPastTop.scrollTop : void 0;
          if (lastTarget !== target) {
            targetBeforeFirstSwap = targetRect[side1];
            pastFirstInvertThresh = false;
            isCircumstantialInvert = !differentRowCol && options.invertSwap || differentLevel;
          }
          direction = _getSwapDirection(evt, target, targetRect, vertical, differentRowCol ? 1 : options.swapThreshold, options.invertedSwapThreshold == null ? options.swapThreshold : options.invertedSwapThreshold, isCircumstantialInvert, lastTarget === target);
          var sibling;
          if (direction !== 0) {
            // Check if target is beside dragEl in respective direction (ignoring hidden elements)
            var dragIndex = index(dragEl);
            do {
              dragIndex -= direction;
              sibling = parentEl.children[dragIndex];
            } while (sibling && (css(sibling, 'display') === 'none' || sibling === ghostEl));
          }
          // If dragEl is already beside target: Do not insert
          if (direction === 0 || sibling === target) {
            return completed(false);
          }
          lastTarget = target;
          lastDirection = direction;
          var nextSibling = target.nextElementSibling,
            after = false;
          after = direction === 1;
          var moveVector = _onMove(rootEl, el, dragEl, dragRect, target, targetRect, evt, after);
          if (moveVector !== false) {
            if (moveVector === 1 || moveVector === -1) {
              after = moveVector === 1;
            }
            _silent = true;
            setTimeout(_unsilent, 30);
            capture();
            if (after && !nextSibling) {
              el.appendChild(dragEl);
            } else {
              target.parentNode.insertBefore(dragEl, after ? nextSibling : target);
            }

            // Undo chrome's scroll adjustment (has no effect on other browsers)
            if (scrolledPastTop) {
              scrollBy(scrolledPastTop, 0, scrollBefore - scrolledPastTop.scrollTop);
            }
            parentEl = dragEl.parentNode; // actualization

            // must be done before animation
            if (targetBeforeFirstSwap !== undefined && !isCircumstantialInvert) {
              targetMoveDistance = Math.abs(targetBeforeFirstSwap - getRect(target)[side1]);
            }
            changed();
            return completed(true);
          }
        }
        if (el.contains(dragEl)) {
          return completed(false);
        }
      }
      return false;
    },
    _ignoreWhileAnimating: null,
    _offMoveEvents: function _offMoveEvents() {
      off(document, 'mousemove', this._onTouchMove);
      off(document, 'touchmove', this._onTouchMove);
      off(document, 'pointermove', this._onTouchMove);
      off(document, 'dragover', nearestEmptyInsertDetectEvent);
      off(document, 'mousemove', nearestEmptyInsertDetectEvent);
      off(document, 'touchmove', nearestEmptyInsertDetectEvent);
    },
    _offUpEvents: function _offUpEvents() {
      var ownerDocument = this.el.ownerDocument;
      off(ownerDocument, 'mouseup', this._onDrop);
      off(ownerDocument, 'touchend', this._onDrop);
      off(ownerDocument, 'pointerup', this._onDrop);
      off(ownerDocument, 'pointercancel', this._onDrop);
      off(ownerDocument, 'touchcancel', this._onDrop);
      off(document, 'selectstart', this);
    },
    _onDrop: function _onDrop( /**Event*/evt) {
      var el = this.el,
        options = this.options;

      // Get the index of the dragged element within its parent
      newIndex = index(dragEl);
      newDraggableIndex = index(dragEl, options.draggable);
      pluginEvent('drop', this, {
        evt: evt
      });
      parentEl = dragEl && dragEl.parentNode;

      // Get again after plugin event
      newIndex = index(dragEl);
      newDraggableIndex = index(dragEl, options.draggable);
      if (Sortable.eventCanceled) {
        this._nulling();
        return;
      }
      awaitingDragStarted = false;
      isCircumstantialInvert = false;
      pastFirstInvertThresh = false;
      clearInterval(this._loopId);
      clearTimeout(this._dragStartTimer);
      _cancelNextTick(this.cloneId);
      _cancelNextTick(this._dragStartId);

      // Unbind events
      if (this.nativeDraggable) {
        off(document, 'drop', this);
        off(el, 'dragstart', this._onDragStart);
      }
      this._offMoveEvents();
      this._offUpEvents();
      if (Safari) {
        css(document.body, 'user-select', '');
      }
      css(dragEl, 'transform', '');
      if (evt) {
        if (moved) {
          evt.cancelable && evt.preventDefault();
          !options.dropBubble && evt.stopPropagation();
        }
        ghostEl && ghostEl.parentNode && ghostEl.parentNode.removeChild(ghostEl);
        if (rootEl === parentEl || putSortable && putSortable.lastPutMode !== 'clone') {
          // Remove clone(s)
          cloneEl && cloneEl.parentNode && cloneEl.parentNode.removeChild(cloneEl);
        }
        if (dragEl) {
          if (this.nativeDraggable) {
            off(dragEl, 'dragend', this);
          }
          _disableDraggable(dragEl);
          dragEl.style['will-change'] = '';

          // Remove classes
          // ghostClass is added in dragStarted
          if (moved && !awaitingDragStarted) {
            toggleClass(dragEl, putSortable ? putSortable.options.ghostClass : this.options.ghostClass, false);
          }
          toggleClass(dragEl, this.options.chosenClass, false);

          // Drag stop event
          _dispatchEvent({
            sortable: this,
            name: 'unchoose',
            toEl: parentEl,
            newIndex: null,
            newDraggableIndex: null,
            originalEvent: evt
          });
          if (rootEl !== parentEl) {
            if (newIndex >= 0) {
              // Add event
              _dispatchEvent({
                rootEl: parentEl,
                name: 'add',
                toEl: parentEl,
                fromEl: rootEl,
                originalEvent: evt
              });

              // Remove event
              _dispatchEvent({
                sortable: this,
                name: 'remove',
                toEl: parentEl,
                originalEvent: evt
              });

              // drag from one list and drop into another
              _dispatchEvent({
                rootEl: parentEl,
                name: 'sort',
                toEl: parentEl,
                fromEl: rootEl,
                originalEvent: evt
              });
              _dispatchEvent({
                sortable: this,
                name: 'sort',
                toEl: parentEl,
                originalEvent: evt
              });
            }
            putSortable && putSortable.save();
          } else {
            if (newIndex !== oldIndex) {
              if (newIndex >= 0) {
                // drag & drop within the same list
                _dispatchEvent({
                  sortable: this,
                  name: 'update',
                  toEl: parentEl,
                  originalEvent: evt
                });
                _dispatchEvent({
                  sortable: this,
                  name: 'sort',
                  toEl: parentEl,
                  originalEvent: evt
                });
              }
            }
          }
          if (Sortable.active) {
            /* jshint eqnull:true */
            if (newIndex == null || newIndex === -1) {
              newIndex = oldIndex;
              newDraggableIndex = oldDraggableIndex;
            }
            _dispatchEvent({
              sortable: this,
              name: 'end',
              toEl: parentEl,
              originalEvent: evt
            });

            // Save sorting
            this.save();
          }
        }
      }
      this._nulling();
    },
    _nulling: function _nulling() {
      pluginEvent('nulling', this);
      rootEl = dragEl = parentEl = ghostEl = nextEl = cloneEl = lastDownEl = cloneHidden = tapEvt = touchEvt = moved = newIndex = newDraggableIndex = oldIndex = oldDraggableIndex = lastTarget = lastDirection = putSortable = activeGroup = Sortable.dragged = Sortable.ghost = Sortable.clone = Sortable.active = null;
      savedInputChecked.forEach(function (el) {
        el.checked = true;
      });
      savedInputChecked.length = lastDx = lastDy = 0;
    },
    handleEvent: function handleEvent( /**Event*/evt) {
      switch (evt.type) {
        case 'drop':
        case 'dragend':
          this._onDrop(evt);
          break;
        case 'dragenter':
        case 'dragover':
          if (dragEl) {
            this._onDragOver(evt);
            _globalDragOver(evt);
          }
          break;
        case 'selectstart':
          evt.preventDefault();
          break;
      }
    },
    /**
     * Serializes the item into an array of string.
     * @returns {String[]}
     */
    toArray: function toArray() {
      var order = [],
        el,
        children = this.el.children,
        i = 0,
        n = children.length,
        options = this.options;
      for (; i < n; i++) {
        el = children[i];
        if (closest(el, options.draggable, this.el, false)) {
          order.push(el.getAttribute(options.dataIdAttr) || _generateId(el));
        }
      }
      return order;
    },
    /**
     * Sorts the elements according to the array.
     * @param  {String[]}  order  order of the items
     */
    sort: function sort(order, useAnimation) {
      var items = {},
        rootEl = this.el;
      this.toArray().forEach(function (id, i) {
        var el = rootEl.children[i];
        if (closest(el, this.options.draggable, rootEl, false)) {
          items[id] = el;
        }
      }, this);
      useAnimation && this.captureAnimationState();
      order.forEach(function (id) {
        if (items[id]) {
          rootEl.removeChild(items[id]);
          rootEl.appendChild(items[id]);
        }
      });
      useAnimation && this.animateAll();
    },
    /**
     * Save the current sorting
     */
    save: function save() {
      var store = this.options.store;
      store && store.set && store.set(this);
    },
    /**
     * For each element in the set, get the first element that matches the selector by testing the element itself and traversing up through its ancestors in the DOM tree.
     * @param   {HTMLElement}  el
     * @param   {String}       [selector]  default: `options.draggable`
     * @returns {HTMLElement|null}
     */
    closest: function closest$1(el, selector) {
      return closest(el, selector || this.options.draggable, this.el, false);
    },
    /**
     * Set/get option
     * @param   {string} name
     * @param   {*}      [value]
     * @returns {*}
     */
    option: function option(name, value) {
      var options = this.options;
      if (value === void 0) {
        return options[name];
      } else {
        var modifiedValue = PluginManager.modifyOption(this, name, value);
        if (typeof modifiedValue !== 'undefined') {
          options[name] = modifiedValue;
        } else {
          options[name] = value;
        }
        if (name === 'group') {
          _prepareGroup(options);
        }
      }
    },
    /**
     * Destroy
     */
    destroy: function destroy() {
      pluginEvent('destroy', this);
      var el = this.el;
      el[expando] = null;
      off(el, 'mousedown', this._onTapStart);
      off(el, 'touchstart', this._onTapStart);
      off(el, 'pointerdown', this._onTapStart);
      if (this.nativeDraggable) {
        off(el, 'dragover', this);
        off(el, 'dragenter', this);
      }
      // Remove draggable attributes
      Array.prototype.forEach.call(el.querySelectorAll('[draggable]'), function (el) {
        el.removeAttribute('draggable');
      });
      this._onDrop();
      this._disableDelayedDragEvents();
      sortables.splice(sortables.indexOf(this.el), 1);
      this.el = el = null;
    },
    _hideClone: function _hideClone() {
      if (!cloneHidden) {
        pluginEvent('hideClone', this);
        if (Sortable.eventCanceled) return;
        css(cloneEl, 'display', 'none');
        if (this.options.removeCloneOnHide && cloneEl.parentNode) {
          cloneEl.parentNode.removeChild(cloneEl);
        }
        cloneHidden = true;
      }
    },
    _showClone: function _showClone(putSortable) {
      if (putSortable.lastPutMode !== 'clone') {
        this._hideClone();
        return;
      }
      if (cloneHidden) {
        pluginEvent('showClone', this);
        if (Sortable.eventCanceled) return;

        // show clone at dragEl or original position
        if (dragEl.parentNode == rootEl && !this.options.group.revertClone) {
          rootEl.insertBefore(cloneEl, dragEl);
        } else if (nextEl) {
          rootEl.insertBefore(cloneEl, nextEl);
        } else {
          rootEl.appendChild(cloneEl);
        }
        if (this.options.group.revertClone) {
          this.animate(dragEl, cloneEl);
        }
        css(cloneEl, 'display', '');
        cloneHidden = false;
      }
    }
  };
  function _globalDragOver( /**Event*/evt) {
    if (evt.dataTransfer) {
      evt.dataTransfer.dropEffect = 'move';
    }
    evt.cancelable && evt.preventDefault();
  }
  function _onMove(fromEl, toEl, dragEl, dragRect, targetEl, targetRect, originalEvent, willInsertAfter) {
    var evt,
      sortable = fromEl[expando],
      onMoveFn = sortable.options.onMove,
      retVal;
    // Support for new CustomEvent feature
    if (window.CustomEvent && !IE11OrLess && !Edge) {
      evt = new CustomEvent('move', {
        bubbles: true,
        cancelable: true
      });
    } else {
      evt = document.createEvent('Event');
      evt.initEvent('move', true, true);
    }
    evt.to = toEl;
    evt.from = fromEl;
    evt.dragged = dragEl;
    evt.draggedRect = dragRect;
    evt.related = targetEl || toEl;
    evt.relatedRect = targetRect || getRect(toEl);
    evt.willInsertAfter = willInsertAfter;
    evt.originalEvent = originalEvent;
    fromEl.dispatchEvent(evt);
    if (onMoveFn) {
      retVal = onMoveFn.call(sortable, evt, originalEvent);
    }
    return retVal;
  }
  function _disableDraggable(el) {
    el.draggable = false;
  }
  function _unsilent() {
    _silent = false;
  }
  function _ghostIsFirst(evt, vertical, sortable) {
    var firstElRect = getRect(getChild(sortable.el, 0, sortable.options, true));
    var childContainingRect = getChildContainingRectFromElement(sortable.el, sortable.options, ghostEl);
    var spacer = 10;
    return vertical ? evt.clientX < childContainingRect.left - spacer || evt.clientY < firstElRect.top && evt.clientX < firstElRect.right : evt.clientY < childContainingRect.top - spacer || evt.clientY < firstElRect.bottom && evt.clientX < firstElRect.left;
  }
  function _ghostIsLast(evt, vertical, sortable) {
    var lastElRect = getRect(lastChild(sortable.el, sortable.options.draggable));
    var childContainingRect = getChildContainingRectFromElement(sortable.el, sortable.options, ghostEl);
    var spacer = 10;
    return vertical ? evt.clientX > childContainingRect.right + spacer || evt.clientY > lastElRect.bottom && evt.clientX > lastElRect.left : evt.clientY > childContainingRect.bottom + spacer || evt.clientX > lastElRect.right && evt.clientY > lastElRect.top;
  }
  function _getSwapDirection(evt, target, targetRect, vertical, swapThreshold, invertedSwapThreshold, invertSwap, isLastTarget) {
    var mouseOnAxis = vertical ? evt.clientY : evt.clientX,
      targetLength = vertical ? targetRect.height : targetRect.width,
      targetS1 = vertical ? targetRect.top : targetRect.left,
      targetS2 = vertical ? targetRect.bottom : targetRect.right,
      invert = false;
    if (!invertSwap) {
      // Never invert or create dragEl shadow when target movemenet causes mouse to move past the end of regular swapThreshold
      if (isLastTarget && targetMoveDistance < targetLength * swapThreshold) {
        // multiplied only by swapThreshold because mouse will already be inside target by (1 - threshold) * targetLength / 2
        // check if past first invert threshold on side opposite of lastDirection
        if (!pastFirstInvertThresh && (lastDirection === 1 ? mouseOnAxis > targetS1 + targetLength * invertedSwapThreshold / 2 : mouseOnAxis < targetS2 - targetLength * invertedSwapThreshold / 2)) {
          // past first invert threshold, do not restrict inverted threshold to dragEl shadow
          pastFirstInvertThresh = true;
        }
        if (!pastFirstInvertThresh) {
          // dragEl shadow (target move distance shadow)
          if (lastDirection === 1 ? mouseOnAxis < targetS1 + targetMoveDistance // over dragEl shadow
          : mouseOnAxis > targetS2 - targetMoveDistance) {
            return -lastDirection;
          }
        } else {
          invert = true;
        }
      } else {
        // Regular
        if (mouseOnAxis > targetS1 + targetLength * (1 - swapThreshold) / 2 && mouseOnAxis < targetS2 - targetLength * (1 - swapThreshold) / 2) {
          return _getInsertDirection(target);
        }
      }
    }
    invert = invert || invertSwap;
    if (invert) {
      // Invert of regular
      if (mouseOnAxis < targetS1 + targetLength * invertedSwapThreshold / 2 || mouseOnAxis > targetS2 - targetLength * invertedSwapThreshold / 2) {
        return mouseOnAxis > targetS1 + targetLength / 2 ? 1 : -1;
      }
    }
    return 0;
  }

  /**
   * Gets the direction dragEl must be swapped relative to target in order to make it
   * seem that dragEl has been "inserted" into that element's position
   * @param  {HTMLElement} target       The target whose position dragEl is being inserted at
   * @return {Number}                   Direction dragEl must be swapped
   */
  function _getInsertDirection(target) {
    if (index(dragEl) < index(target)) {
      return 1;
    } else {
      return -1;
    }
  }

  /**
   * Generate id
   * @param   {HTMLElement} el
   * @returns {String}
   * @private
   */
  function _generateId(el) {
    var str = el.tagName + el.className + el.src + el.href + el.textContent,
      i = str.length,
      sum = 0;
    while (i--) {
      sum += str.charCodeAt(i);
    }
    return sum.toString(36);
  }
  function _saveInputCheckedState(root) {
    savedInputChecked.length = 0;
    var inputs = root.getElementsByTagName('input');
    var idx = inputs.length;
    while (idx--) {
      var el = inputs[idx];
      el.checked && savedInputChecked.push(el);
    }
  }
  function _nextTick(fn) {
    return setTimeout(fn, 0);
  }
  function _cancelNextTick(id) {
    return clearTimeout(id);
  }

  // Fixed #973:
  if (documentExists) {
    on(document, 'touchmove', function (evt) {
      if ((Sortable.active || awaitingDragStarted) && evt.cancelable) {
        evt.preventDefault();
      }
    });
  }

  // Export utils
  Sortable.utils = {
    on: on,
    off: off,
    css: css,
    find: find,
    is: function is(el, selector) {
      return !!closest(el, selector, el, false);
    },
    extend: extend,
    throttle: throttle,
    closest: closest,
    toggleClass: toggleClass,
    clone: clone,
    index: index,
    nextTick: _nextTick,
    cancelNextTick: _cancelNextTick,
    detectDirection: _detectDirection,
    getChild: getChild,
    expando: expando
  };

  /**
   * Get the Sortable instance of an element
   * @param  {HTMLElement} element The element
   * @return {Sortable|undefined}         The instance of Sortable
   */
  Sortable.get = function (element) {
    return element[expando];
  };

  /**
   * Mount a plugin to Sortable
   * @param  {...SortablePlugin|SortablePlugin[]} plugins       Plugins being mounted
   */
  Sortable.mount = function () {
    for (var _len = arguments.length, plugins = new Array(_len), _key = 0; _key < _len; _key++) {
      plugins[_key] = arguments[_key];
    }
    if (plugins[0].constructor === Array) plugins = plugins[0];
    plugins.forEach(function (plugin) {
      if (!plugin.prototype || !plugin.prototype.constructor) {
        throw "Sortable: Mounted plugin must be a constructor function, not ".concat({}.toString.call(plugin));
      }
      if (plugin.utils) Sortable.utils = _objectSpread2(_objectSpread2({}, Sortable.utils), plugin.utils);
      PluginManager.mount(plugin);
    });
  };

  /**
   * Create sortable instance
   * @param {HTMLElement}  el
   * @param {Object}      [options]
   */
  Sortable.create = function (el, options) {
    return new Sortable(el, options);
  };

  // Export
  Sortable.version = version;

  var autoScrolls = [],
    scrollEl,
    scrollRootEl,
    scrolling = false,
    lastAutoScrollX,
    lastAutoScrollY,
    touchEvt$1,
    pointerElemChangedInterval;
  function AutoScrollPlugin() {
    function AutoScroll() {
      this.defaults = {
        scroll: true,
        forceAutoScrollFallback: false,
        scrollSensitivity: 30,
        scrollSpeed: 10,
        bubbleScroll: true
      };

      // Bind all private methods
      for (var fn in this) {
        if (fn.charAt(0) === '_' && typeof this[fn] === 'function') {
          this[fn] = this[fn].bind(this);
        }
      }
    }
    AutoScroll.prototype = {
      dragStarted: function dragStarted(_ref) {
        var originalEvent = _ref.originalEvent;
        if (this.sortable.nativeDraggable) {
          on(document, 'dragover', this._handleAutoScroll);
        } else {
          if (this.options.supportPointer) {
            on(document, 'pointermove', this._handleFallbackAutoScroll);
          } else if (originalEvent.touches) {
            on(document, 'touchmove', this._handleFallbackAutoScroll);
          } else {
            on(document, 'mousemove', this._handleFallbackAutoScroll);
          }
        }
      },
      dragOverCompleted: function dragOverCompleted(_ref2) {
        var originalEvent = _ref2.originalEvent;
        // For when bubbling is canceled and using fallback (fallback 'touchmove' always reached)
        if (!this.options.dragOverBubble && !originalEvent.rootEl) {
          this._handleAutoScroll(originalEvent);
        }
      },
      drop: function drop() {
        if (this.sortable.nativeDraggable) {
          off(document, 'dragover', this._handleAutoScroll);
        } else {
          off(document, 'pointermove', this._handleFallbackAutoScroll);
          off(document, 'touchmove', this._handleFallbackAutoScroll);
          off(document, 'mousemove', this._handleFallbackAutoScroll);
        }
        clearPointerElemChangedInterval();
        clearAutoScrolls();
        cancelThrottle();
      },
      nulling: function nulling() {
        touchEvt$1 = scrollRootEl = scrollEl = scrolling = pointerElemChangedInterval = lastAutoScrollX = lastAutoScrollY = null;
        autoScrolls.length = 0;
      },
      _handleFallbackAutoScroll: function _handleFallbackAutoScroll(evt) {
        this._handleAutoScroll(evt, true);
      },
      _handleAutoScroll: function _handleAutoScroll(evt, fallback) {
        var _this = this;
        var x = (evt.touches ? evt.touches[0] : evt).clientX,
          y = (evt.touches ? evt.touches[0] : evt).clientY,
          elem = document.elementFromPoint(x, y);
        touchEvt$1 = evt;

        // IE does not seem to have native autoscroll,
        // Edge's autoscroll seems too conditional,
        // MACOS Safari does not have autoscroll,
        // Firefox and Chrome are good
        if (fallback || this.options.forceAutoScrollFallback || Edge || IE11OrLess || Safari) {
          autoScroll(evt, this.options, elem, fallback);

          // Listener for pointer element change
          var ogElemScroller = getParentAutoScrollElement(elem, true);
          if (scrolling && (!pointerElemChangedInterval || x !== lastAutoScrollX || y !== lastAutoScrollY)) {
            pointerElemChangedInterval && clearPointerElemChangedInterval();
            // Detect for pointer elem change, emulating native DnD behaviour
            pointerElemChangedInterval = setInterval(function () {
              var newElem = getParentAutoScrollElement(document.elementFromPoint(x, y), true);
              if (newElem !== ogElemScroller) {
                ogElemScroller = newElem;
                clearAutoScrolls();
              }
              autoScroll(evt, _this.options, newElem, fallback);
            }, 10);
            lastAutoScrollX = x;
            lastAutoScrollY = y;
          }
        } else {
          // if DnD is enabled (and browser has good autoscrolling), first autoscroll will already scroll, so get parent autoscroll of first autoscroll
          if (!this.options.bubbleScroll || getParentAutoScrollElement(elem, true) === getWindowScrollingElement()) {
            clearAutoScrolls();
            return;
          }
          autoScroll(evt, this.options, getParentAutoScrollElement(elem, false), false);
        }
      }
    };
    return _extends(AutoScroll, {
      pluginName: 'scroll',
      initializeByDefault: true
    });
  }
  function clearAutoScrolls() {
    autoScrolls.forEach(function (autoScroll) {
      clearInterval(autoScroll.pid);
    });
    autoScrolls = [];
  }
  function clearPointerElemChangedInterval() {
    clearInterval(pointerElemChangedInterval);
  }
  var autoScroll = throttle(function (evt, options, rootEl, isFallback) {
    // Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=505521
    if (!options.scroll) return;
    var x = (evt.touches ? evt.touches[0] : evt).clientX,
      y = (evt.touches ? evt.touches[0] : evt).clientY,
      sens = options.scrollSensitivity,
      speed = options.scrollSpeed,
      winScroller = getWindowScrollingElement();
    var scrollThisInstance = false,
      scrollCustomFn;

    // New scroll root, set scrollEl
    if (scrollRootEl !== rootEl) {
      scrollRootEl = rootEl;
      clearAutoScrolls();
      scrollEl = options.scroll;
      scrollCustomFn = options.scrollFn;
      if (scrollEl === true) {
        scrollEl = getParentAutoScrollElement(rootEl, true);
      }
    }
    var layersOut = 0;
    var currentParent = scrollEl;
    do {
      var el = currentParent,
        rect = getRect(el),
        top = rect.top,
        bottom = rect.bottom,
        left = rect.left,
        right = rect.right,
        width = rect.width,
        height = rect.height,
        canScrollX = void 0,
        canScrollY = void 0,
        scrollWidth = el.scrollWidth,
        scrollHeight = el.scrollHeight,
        elCSS = css(el),
        scrollPosX = el.scrollLeft,
        scrollPosY = el.scrollTop;
      if (el === winScroller) {
        canScrollX = width < scrollWidth && (elCSS.overflowX === 'auto' || elCSS.overflowX === 'scroll' || elCSS.overflowX === 'visible');
        canScrollY = height < scrollHeight && (elCSS.overflowY === 'auto' || elCSS.overflowY === 'scroll' || elCSS.overflowY === 'visible');
      } else {
        canScrollX = width < scrollWidth && (elCSS.overflowX === 'auto' || elCSS.overflowX === 'scroll');
        canScrollY = height < scrollHeight && (elCSS.overflowY === 'auto' || elCSS.overflowY === 'scroll');
      }
      var vx = canScrollX && (Math.abs(right - x) <= sens && scrollPosX + width < scrollWidth) - (Math.abs(left - x) <= sens && !!scrollPosX);
      var vy = canScrollY && (Math.abs(bottom - y) <= sens && scrollPosY + height < scrollHeight) - (Math.abs(top - y) <= sens && !!scrollPosY);
      if (!autoScrolls[layersOut]) {
        for (var i = 0; i <= layersOut; i++) {
          if (!autoScrolls[i]) {
            autoScrolls[i] = {};
          }
        }
      }
      if (autoScrolls[layersOut].vx != vx || autoScrolls[layersOut].vy != vy || autoScrolls[layersOut].el !== el) {
        autoScrolls[layersOut].el = el;
        autoScrolls[layersOut].vx = vx;
        autoScrolls[layersOut].vy = vy;
        clearInterval(autoScrolls[layersOut].pid);
        if (vx != 0 || vy != 0) {
          scrollThisInstance = true;
          /* jshint loopfunc:true */
          autoScrolls[layersOut].pid = setInterval(function () {
            // emulate drag over during autoscroll (fallback), emulating native DnD behaviour
            if (isFallback && this.layer === 0) {
              Sortable.active._onTouchMove(touchEvt$1); // To move ghost if it is positioned absolutely
            }
            var scrollOffsetY = autoScrolls[this.layer].vy ? autoScrolls[this.layer].vy * speed : 0;
            var scrollOffsetX = autoScrolls[this.layer].vx ? autoScrolls[this.layer].vx * speed : 0;
            if (typeof scrollCustomFn === 'function') {
              if (scrollCustomFn.call(Sortable.dragged.parentNode[expando], scrollOffsetX, scrollOffsetY, evt, touchEvt$1, autoScrolls[this.layer].el) !== 'continue') {
                return;
              }
            }
            scrollBy(autoScrolls[this.layer].el, scrollOffsetX, scrollOffsetY);
          }.bind({
            layer: layersOut
          }), 24);
        }
      }
      layersOut++;
    } while (options.bubbleScroll && currentParent !== winScroller && (currentParent = getParentAutoScrollElement(currentParent, false)));
    scrolling = scrollThisInstance; // in case another function catches scrolling as false in between when it is not
  }, 30);

  var drop = function drop(_ref) {
    var originalEvent = _ref.originalEvent,
      putSortable = _ref.putSortable,
      dragEl = _ref.dragEl,
      activeSortable = _ref.activeSortable,
      dispatchSortableEvent = _ref.dispatchSortableEvent,
      hideGhostForTarget = _ref.hideGhostForTarget,
      unhideGhostForTarget = _ref.unhideGhostForTarget;
    if (!originalEvent) return;
    var toSortable = putSortable || activeSortable;
    hideGhostForTarget();
    var touch = originalEvent.changedTouches && originalEvent.changedTouches.length ? originalEvent.changedTouches[0] : originalEvent;
    var target = document.elementFromPoint(touch.clientX, touch.clientY);
    unhideGhostForTarget();
    if (toSortable && !toSortable.el.contains(target)) {
      dispatchSortableEvent('spill');
      this.onSpill({
        dragEl: dragEl,
        putSortable: putSortable
      });
    }
  };
  function Revert() {}
  Revert.prototype = {
    startIndex: null,
    dragStart: function dragStart(_ref2) {
      var oldDraggableIndex = _ref2.oldDraggableIndex;
      this.startIndex = oldDraggableIndex;
    },
    onSpill: function onSpill(_ref3) {
      var dragEl = _ref3.dragEl,
        putSortable = _ref3.putSortable;
      this.sortable.captureAnimationState();
      if (putSortable) {
        putSortable.captureAnimationState();
      }
      var nextSibling = getChild(this.sortable.el, this.startIndex, this.options);
      if (nextSibling) {
        this.sortable.el.insertBefore(dragEl, nextSibling);
      } else {
        this.sortable.el.appendChild(dragEl);
      }
      this.sortable.animateAll();
      if (putSortable) {
        putSortable.animateAll();
      }
    },
    drop: drop
  };
  _extends(Revert, {
    pluginName: 'revertOnSpill'
  });
  function Remove() {}
  Remove.prototype = {
    onSpill: function onSpill(_ref4) {
      var dragEl = _ref4.dragEl,
        putSortable = _ref4.putSortable;
      var parentSortable = putSortable || this.sortable;
      parentSortable.captureAnimationState();
      dragEl.parentNode && dragEl.parentNode.removeChild(dragEl);
      parentSortable.animateAll();
    },
    drop: drop
  };
  _extends(Remove, {
    pluginName: 'removeOnSpill'
  });

  var lastSwapEl;
  function SwapPlugin() {
    function Swap() {
      this.defaults = {
        swapClass: 'sortable-swap-highlight'
      };
    }
    Swap.prototype = {
      dragStart: function dragStart(_ref) {
        var dragEl = _ref.dragEl;
        lastSwapEl = dragEl;
      },
      dragOverValid: function dragOverValid(_ref2) {
        var completed = _ref2.completed,
          target = _ref2.target,
          onMove = _ref2.onMove,
          activeSortable = _ref2.activeSortable,
          changed = _ref2.changed,
          cancel = _ref2.cancel;
        if (!activeSortable.options.swap) return;
        var el = this.sortable.el,
          options = this.options;
        if (target && target !== el) {
          var prevSwapEl = lastSwapEl;
          if (onMove(target) !== false) {
            toggleClass(target, options.swapClass, true);
            lastSwapEl = target;
          } else {
            lastSwapEl = null;
          }
          if (prevSwapEl && prevSwapEl !== lastSwapEl) {
            toggleClass(prevSwapEl, options.swapClass, false);
          }
        }
        changed();
        completed(true);
        cancel();
      },
      drop: function drop(_ref3) {
        var activeSortable = _ref3.activeSortable,
          putSortable = _ref3.putSortable,
          dragEl = _ref3.dragEl;
        var toSortable = putSortable || this.sortable;
        var options = this.options;
        lastSwapEl && toggleClass(lastSwapEl, options.swapClass, false);
        if (lastSwapEl && (options.swap || putSortable && putSortable.options.swap)) {
          if (dragEl !== lastSwapEl) {
            toSortable.captureAnimationState();
            if (toSortable !== activeSortable) activeSortable.captureAnimationState();
            swapNodes(dragEl, lastSwapEl);
            toSortable.animateAll();
            if (toSortable !== activeSortable) activeSortable.animateAll();
          }
        }
      },
      nulling: function nulling() {
        lastSwapEl = null;
      }
    };
    return _extends(Swap, {
      pluginName: 'swap',
      eventProperties: function eventProperties() {
        return {
          swapItem: lastSwapEl
        };
      }
    });
  }
  function swapNodes(n1, n2) {
    var p1 = n1.parentNode,
      p2 = n2.parentNode,
      i1,
      i2;
    if (!p1 || !p2 || p1.isEqualNode(n2) || p2.isEqualNode(n1)) return;
    i1 = index(n1);
    i2 = index(n2);
    if (p1.isEqualNode(p2) && i1 < i2) {
      i2++;
    }
    p1.insertBefore(n2, p1.children[i1]);
    p2.insertBefore(n1, p2.children[i2]);
  }

  var multiDragElements = [],
    multiDragClones = [],
    lastMultiDragSelect,
    // for selection with modifier key down (SHIFT)
    multiDragSortable,
    initialFolding = false,
    // Initial multi-drag fold when drag started
    folding = false,
    // Folding any other time
    dragStarted = false,
    dragEl$1,
    clonesFromRect,
    clonesHidden;
  function MultiDragPlugin() {
    function MultiDrag(sortable) {
      // Bind all private methods
      for (var fn in this) {
        if (fn.charAt(0) === '_' && typeof this[fn] === 'function') {
          this[fn] = this[fn].bind(this);
        }
      }
      if (!sortable.options.avoidImplicitDeselect) {
        if (sortable.options.supportPointer) {
          on(document, 'pointerup', this._deselectMultiDrag);
        } else {
          on(document, 'mouseup', this._deselectMultiDrag);
          on(document, 'touchend', this._deselectMultiDrag);
        }
      }
      on(document, 'keydown', this._checkKeyDown);
      on(document, 'keyup', this._checkKeyUp);
      this.defaults = {
        selectedClass: 'sortable-selected',
        multiDragKey: null,
        avoidImplicitDeselect: false,
        setData: function setData(dataTransfer, dragEl) {
          var data = '';
          if (multiDragElements.length && multiDragSortable === sortable) {
            multiDragElements.forEach(function (multiDragElement, i) {
              data += (!i ? '' : ', ') + multiDragElement.textContent;
            });
          } else {
            data = dragEl.textContent;
          }
          dataTransfer.setData('Text', data);
        }
      };
    }
    MultiDrag.prototype = {
      multiDragKeyDown: false,
      isMultiDrag: false,
      delayStartGlobal: function delayStartGlobal(_ref) {
        var dragged = _ref.dragEl;
        dragEl$1 = dragged;
      },
      delayEnded: function delayEnded() {
        this.isMultiDrag = ~multiDragElements.indexOf(dragEl$1);
      },
      setupClone: function setupClone(_ref2) {
        var sortable = _ref2.sortable,
          cancel = _ref2.cancel;
        if (!this.isMultiDrag) return;
        for (var i = 0; i < multiDragElements.length; i++) {
          multiDragClones.push(clone(multiDragElements[i]));
          multiDragClones[i].sortableIndex = multiDragElements[i].sortableIndex;
          multiDragClones[i].draggable = false;
          multiDragClones[i].style['will-change'] = '';
          toggleClass(multiDragClones[i], this.options.selectedClass, false);
          multiDragElements[i] === dragEl$1 && toggleClass(multiDragClones[i], this.options.chosenClass, false);
        }
        sortable._hideClone();
        cancel();
      },
      clone: function clone(_ref3) {
        var sortable = _ref3.sortable,
          rootEl = _ref3.rootEl,
          dispatchSortableEvent = _ref3.dispatchSortableEvent,
          cancel = _ref3.cancel;
        if (!this.isMultiDrag) return;
        if (!this.options.removeCloneOnHide) {
          if (multiDragElements.length && multiDragSortable === sortable) {
            insertMultiDragClones(true, rootEl);
            dispatchSortableEvent('clone');
            cancel();
          }
        }
      },
      showClone: function showClone(_ref4) {
        var cloneNowShown = _ref4.cloneNowShown,
          rootEl = _ref4.rootEl,
          cancel = _ref4.cancel;
        if (!this.isMultiDrag) return;
        insertMultiDragClones(false, rootEl);
        multiDragClones.forEach(function (clone) {
          css(clone, 'display', '');
        });
        cloneNowShown();
        clonesHidden = false;
        cancel();
      },
      hideClone: function hideClone(_ref5) {
        var _this = this;
        var sortable = _ref5.sortable,
          cloneNowHidden = _ref5.cloneNowHidden,
          cancel = _ref5.cancel;
        if (!this.isMultiDrag) return;
        multiDragClones.forEach(function (clone) {
          css(clone, 'display', 'none');
          if (_this.options.removeCloneOnHide && clone.parentNode) {
            clone.parentNode.removeChild(clone);
          }
        });
        cloneNowHidden();
        clonesHidden = true;
        cancel();
      },
      dragStartGlobal: function dragStartGlobal(_ref6) {
        var sortable = _ref6.sortable;
        if (!this.isMultiDrag && multiDragSortable) {
          multiDragSortable.multiDrag._deselectMultiDrag();
        }
        multiDragElements.forEach(function (multiDragElement) {
          multiDragElement.sortableIndex = index(multiDragElement);
        });

        // Sort multi-drag elements
        multiDragElements = multiDragElements.sort(function (a, b) {
          return a.sortableIndex - b.sortableIndex;
        });
        dragStarted = true;
      },
      dragStarted: function dragStarted(_ref7) {
        var _this2 = this;
        var sortable = _ref7.sortable;
        if (!this.isMultiDrag) return;
        if (this.options.sort) {
          // Capture rects,
          // hide multi drag elements (by positioning them absolute),
          // set multi drag elements rects to dragRect,
          // show multi drag elements,
          // animate to rects,
          // unset rects & remove from DOM

          sortable.captureAnimationState();
          if (this.options.animation) {
            multiDragElements.forEach(function (multiDragElement) {
              if (multiDragElement === dragEl$1) return;
              css(multiDragElement, 'position', 'absolute');
            });
            var dragRect = getRect(dragEl$1, false, true, true);
            multiDragElements.forEach(function (multiDragElement) {
              if (multiDragElement === dragEl$1) return;
              setRect(multiDragElement, dragRect);
            });
            folding = true;
            initialFolding = true;
          }
        }
        sortable.animateAll(function () {
          folding = false;
          initialFolding = false;
          if (_this2.options.animation) {
            multiDragElements.forEach(function (multiDragElement) {
              unsetRect(multiDragElement);
            });
          }

          // Remove all auxiliary multidrag items from el, if sorting enabled
          if (_this2.options.sort) {
            removeMultiDragElements();
          }
        });
      },
      dragOver: function dragOver(_ref8) {
        var target = _ref8.target,
          completed = _ref8.completed,
          cancel = _ref8.cancel;
        if (folding && ~multiDragElements.indexOf(target)) {
          completed(false);
          cancel();
        }
      },
      revert: function revert(_ref9) {
        var fromSortable = _ref9.fromSortable,
          rootEl = _ref9.rootEl,
          sortable = _ref9.sortable,
          dragRect = _ref9.dragRect;
        if (multiDragElements.length > 1) {
          // Setup unfold animation
          multiDragElements.forEach(function (multiDragElement) {
            sortable.addAnimationState({
              target: multiDragElement,
              rect: folding ? getRect(multiDragElement) : dragRect
            });
            unsetRect(multiDragElement);
            multiDragElement.fromRect = dragRect;
            fromSortable.removeAnimationState(multiDragElement);
          });
          folding = false;
          insertMultiDragElements(!this.options.removeCloneOnHide, rootEl);
        }
      },
      dragOverCompleted: function dragOverCompleted(_ref10) {
        var sortable = _ref10.sortable,
          isOwner = _ref10.isOwner,
          insertion = _ref10.insertion,
          activeSortable = _ref10.activeSortable,
          parentEl = _ref10.parentEl,
          putSortable = _ref10.putSortable;
        var options = this.options;
        if (insertion) {
          // Clones must be hidden before folding animation to capture dragRectAbsolute properly
          if (isOwner) {
            activeSortable._hideClone();
          }
          initialFolding = false;
          // If leaving sort:false root, or already folding - Fold to new location
          if (options.animation && multiDragElements.length > 1 && (folding || !isOwner && !activeSortable.options.sort && !putSortable)) {
            // Fold: Set all multi drag elements's rects to dragEl's rect when multi-drag elements are invisible
            var dragRectAbsolute = getRect(dragEl$1, false, true, true);
            multiDragElements.forEach(function (multiDragElement) {
              if (multiDragElement === dragEl$1) return;
              setRect(multiDragElement, dragRectAbsolute);

              // Move element(s) to end of parentEl so that it does not interfere with multi-drag clones insertion if they are inserted
              // while folding, and so that we can capture them again because old sortable will no longer be fromSortable
              parentEl.appendChild(multiDragElement);
            });
            folding = true;
          }

          // Clones must be shown (and check to remove multi drags) after folding when interfering multiDragElements are moved out
          if (!isOwner) {
            // Only remove if not folding (folding will remove them anyways)
            if (!folding) {
              removeMultiDragElements();
            }
            if (multiDragElements.length > 1) {
              var clonesHiddenBefore = clonesHidden;
              activeSortable._showClone(sortable);

              // Unfold animation for clones if showing from hidden
              if (activeSortable.options.animation && !clonesHidden && clonesHiddenBefore) {
                multiDragClones.forEach(function (clone) {
                  activeSortable.addAnimationState({
                    target: clone,
                    rect: clonesFromRect
                  });
                  clone.fromRect = clonesFromRect;
                  clone.thisAnimationDuration = null;
                });
              }
            } else {
              activeSortable._showClone(sortable);
            }
          }
        }
      },
      dragOverAnimationCapture: function dragOverAnimationCapture(_ref11) {
        var dragRect = _ref11.dragRect,
          isOwner = _ref11.isOwner,
          activeSortable = _ref11.activeSortable;
        multiDragElements.forEach(function (multiDragElement) {
          multiDragElement.thisAnimationDuration = null;
        });
        if (activeSortable.options.animation && !isOwner && activeSortable.multiDrag.isMultiDrag) {
          clonesFromRect = _extends({}, dragRect);
          var dragMatrix = matrix(dragEl$1, true);
          clonesFromRect.top -= dragMatrix.f;
          clonesFromRect.left -= dragMatrix.e;
        }
      },
      dragOverAnimationComplete: function dragOverAnimationComplete() {
        if (folding) {
          folding = false;
          removeMultiDragElements();
        }
      },
      drop: function drop(_ref12) {
        var evt = _ref12.originalEvent,
          rootEl = _ref12.rootEl,
          parentEl = _ref12.parentEl,
          sortable = _ref12.sortable,
          dispatchSortableEvent = _ref12.dispatchSortableEvent,
          oldIndex = _ref12.oldIndex,
          putSortable = _ref12.putSortable;
        var toSortable = putSortable || this.sortable;
        if (!evt) return;
        var options = this.options,
          children = parentEl.children;

        // Multi-drag selection
        if (!dragStarted) {
          if (options.multiDragKey && !this.multiDragKeyDown) {
            this._deselectMultiDrag();
          }
          toggleClass(dragEl$1, options.selectedClass, !~multiDragElements.indexOf(dragEl$1));
          if (!~multiDragElements.indexOf(dragEl$1)) {
            multiDragElements.push(dragEl$1);
            dispatchEvent({
              sortable: sortable,
              rootEl: rootEl,
              name: 'select',
              targetEl: dragEl$1,
              originalEvent: evt
            });

            // Modifier activated, select from last to dragEl
            if (evt.shiftKey && lastMultiDragSelect && sortable.el.contains(lastMultiDragSelect)) {
              var lastIndex = index(lastMultiDragSelect),
                currentIndex = index(dragEl$1);
              if (~lastIndex && ~currentIndex && lastIndex !== currentIndex) {
                (function () {
                  // Must include lastMultiDragSelect (select it), in case modified selection from no selection
                  // (but previous selection existed)
                  var n, i;
                  if (currentIndex > lastIndex) {
                    i = lastIndex;
                    n = currentIndex;
                  } else {
                    i = currentIndex;
                    n = lastIndex + 1;
                  }
                  var filter = options.filter;
                  for (; i < n; i++) {
                    if (~multiDragElements.indexOf(children[i])) continue;
                    // Check if element is draggable
                    if (!closest(children[i], options.draggable, parentEl, false)) continue;
                    // Check if element is filtered
                    var filtered = filter && (typeof filter === 'function' ? filter.call(sortable, evt, children[i], sortable) : filter.split(',').some(function (criteria) {
                      return closest(children[i], criteria.trim(), parentEl, false);
                    }));
                    if (filtered) continue;
                    toggleClass(children[i], options.selectedClass, true);
                    multiDragElements.push(children[i]);
                    dispatchEvent({
                      sortable: sortable,
                      rootEl: rootEl,
                      name: 'select',
                      targetEl: children[i],
                      originalEvent: evt
                    });
                  }
                })();
              }
            } else {
              lastMultiDragSelect = dragEl$1;
            }
            multiDragSortable = toSortable;
          } else {
            multiDragElements.splice(multiDragElements.indexOf(dragEl$1), 1);
            lastMultiDragSelect = null;
            dispatchEvent({
              sortable: sortable,
              rootEl: rootEl,
              name: 'deselect',
              targetEl: dragEl$1,
              originalEvent: evt
            });
          }
        }

        // Multi-drag drop
        if (dragStarted && this.isMultiDrag) {
          folding = false;
          // Do not "unfold" after around dragEl if reverted
          if ((parentEl[expando].options.sort || parentEl !== rootEl) && multiDragElements.length > 1) {
            var dragRect = getRect(dragEl$1),
              multiDragIndex = index(dragEl$1, ':not(.' + this.options.selectedClass + ')');
            if (!initialFolding && options.animation) dragEl$1.thisAnimationDuration = null;
            toSortable.captureAnimationState();
            if (!initialFolding) {
              if (options.animation) {
                dragEl$1.fromRect = dragRect;
                multiDragElements.forEach(function (multiDragElement) {
                  multiDragElement.thisAnimationDuration = null;
                  if (multiDragElement !== dragEl$1) {
                    var rect = folding ? getRect(multiDragElement) : dragRect;
                    multiDragElement.fromRect = rect;

                    // Prepare unfold animation
                    toSortable.addAnimationState({
                      target: multiDragElement,
                      rect: rect
                    });
                  }
                });
              }

              // Multi drag elements are not necessarily removed from the DOM on drop, so to reinsert
              // properly they must all be removed
              removeMultiDragElements();
              multiDragElements.forEach(function (multiDragElement) {
                if (children[multiDragIndex]) {
                  parentEl.insertBefore(multiDragElement, children[multiDragIndex]);
                } else {
                  parentEl.appendChild(multiDragElement);
                }
                multiDragIndex++;
              });

              // If initial folding is done, the elements may have changed position because they are now
              // unfolding around dragEl, even though dragEl may not have his index changed, so update event
              // must be fired here as Sortable will not.
              if (oldIndex === index(dragEl$1)) {
                var update = false;
                multiDragElements.forEach(function (multiDragElement) {
                  if (multiDragElement.sortableIndex !== index(multiDragElement)) {
                    update = true;
                    return;
                  }
                });
                if (update) {
                  dispatchSortableEvent('update');
                  dispatchSortableEvent('sort');
                }
              }
            }

            // Must be done after capturing individual rects (scroll bar)
            multiDragElements.forEach(function (multiDragElement) {
              unsetRect(multiDragElement);
            });
            toSortable.animateAll();
          }
          multiDragSortable = toSortable;
        }

        // Remove clones if necessary
        if (rootEl === parentEl || putSortable && putSortable.lastPutMode !== 'clone') {
          multiDragClones.forEach(function (clone) {
            clone.parentNode && clone.parentNode.removeChild(clone);
          });
        }
      },
      nullingGlobal: function nullingGlobal() {
        this.isMultiDrag = dragStarted = false;
        multiDragClones.length = 0;
      },
      destroyGlobal: function destroyGlobal() {
        this._deselectMultiDrag();
        off(document, 'pointerup', this._deselectMultiDrag);
        off(document, 'mouseup', this._deselectMultiDrag);
        off(document, 'touchend', this._deselectMultiDrag);
        off(document, 'keydown', this._checkKeyDown);
        off(document, 'keyup', this._checkKeyUp);
      },
      _deselectMultiDrag: function _deselectMultiDrag(evt) {
        if (typeof dragStarted !== "undefined" && dragStarted) return;

        // Only deselect if selection is in this sortable
        if (multiDragSortable !== this.sortable) return;

        // Only deselect if target is not item in this sortable
        if (evt && closest(evt.target, this.options.draggable, this.sortable.el, false)) return;

        // Only deselect if left click
        if (evt && evt.button !== 0) return;
        while (multiDragElements.length) {
          var el = multiDragElements[0];
          toggleClass(el, this.options.selectedClass, false);
          multiDragElements.shift();
          dispatchEvent({
            sortable: this.sortable,
            rootEl: this.sortable.el,
            name: 'deselect',
            targetEl: el,
            originalEvent: evt
          });
        }
      },
      _checkKeyDown: function _checkKeyDown(evt) {
        if (evt.key === this.options.multiDragKey) {
          this.multiDragKeyDown = true;
        }
      },
      _checkKeyUp: function _checkKeyUp(evt) {
        if (evt.key === this.options.multiDragKey) {
          this.multiDragKeyDown = false;
        }
      }
    };
    return _extends(MultiDrag, {
      // Static methods & properties
      pluginName: 'multiDrag',
      utils: {
        /**
         * Selects the provided multi-drag item
         * @param  {HTMLElement} el    The element to be selected
         */
        select: function select(el) {
          var sortable = el.parentNode[expando];
          if (!sortable || !sortable.options.multiDrag || ~multiDragElements.indexOf(el)) return;
          if (multiDragSortable && multiDragSortable !== sortable) {
            multiDragSortable.multiDrag._deselectMultiDrag();
            multiDragSortable = sortable;
          }
          toggleClass(el, sortable.options.selectedClass, true);
          multiDragElements.push(el);
        },
        /**
         * Deselects the provided multi-drag item
         * @param  {HTMLElement} el    The element to be deselected
         */
        deselect: function deselect(el) {
          var sortable = el.parentNode[expando],
            index = multiDragElements.indexOf(el);
          if (!sortable || !sortable.options.multiDrag || !~index) return;
          toggleClass(el, sortable.options.selectedClass, false);
          multiDragElements.splice(index, 1);
        }
      },
      eventProperties: function eventProperties() {
        var _this3 = this;
        var oldIndicies = [],
          newIndicies = [];
        multiDragElements.forEach(function (multiDragElement) {
          oldIndicies.push({
            multiDragElement: multiDragElement,
            index: multiDragElement.sortableIndex
          });

          // multiDragElements will already be sorted if folding
          var newIndex;
          if (folding && multiDragElement !== dragEl$1) {
            newIndex = -1;
          } else if (folding) {
            newIndex = index(multiDragElement, ':not(.' + _this3.options.selectedClass + ')');
          } else {
            newIndex = index(multiDragElement);
          }
          newIndicies.push({
            multiDragElement: multiDragElement,
            index: newIndex
          });
        });
        return {
          items: _toConsumableArray(multiDragElements),
          clones: [].concat(multiDragClones),
          oldIndicies: oldIndicies,
          newIndicies: newIndicies
        };
      },
      optionListeners: {
        multiDragKey: function multiDragKey(key) {
          key = key.toLowerCase();
          if (key === 'ctrl') {
            key = 'Control';
          } else if (key.length > 1) {
            key = key.charAt(0).toUpperCase() + key.substr(1);
          }
          return key;
        }
      }
    });
  }
  function insertMultiDragElements(clonesInserted, rootEl) {
    multiDragElements.forEach(function (multiDragElement, i) {
      var target = rootEl.children[multiDragElement.sortableIndex + (clonesInserted ? Number(i) : 0)];
      if (target) {
        rootEl.insertBefore(multiDragElement, target);
      } else {
        rootEl.appendChild(multiDragElement);
      }
    });
  }

  /**
   * Insert multi-drag clones
   * @param  {[Boolean]} elementsInserted  Whether the multi-drag elements are inserted
   * @param  {HTMLElement} rootEl
   */
  function insertMultiDragClones(elementsInserted, rootEl) {
    multiDragClones.forEach(function (clone, i) {
      var target = rootEl.children[clone.sortableIndex + (elementsInserted ? Number(i) : 0)];
      if (target) {
        rootEl.insertBefore(clone, target);
      } else {
        rootEl.appendChild(clone);
      }
    });
  }
  function removeMultiDragElements() {
    multiDragElements.forEach(function (multiDragElement) {
      if (multiDragElement === dragEl$1) return;
      multiDragElement.parentNode && multiDragElement.parentNode.removeChild(multiDragElement);
    });
  }

  Sortable.mount(new AutoScrollPlugin());
  Sortable.mount(Remove, Revert);

  Sortable.mount(new SwapPlugin());
  Sortable.mount(new MultiDragPlugin());

  return Sortable;

})));