bootstrap.bundle.js

   * @argument {Object} data - The data object generated by `update` method
   * @argument {Object} options - Modifiers configuration and options
   * @returns {Object} The data object, properly modified
   */
  function shift(data) {
    var placement = data.placement;
    var basePlacement = placement.split('-')[0];
    var shiftvariation = placement.split('-')[1];

    // if shift shiftvariation is specified, run the modifier
    if (shiftvariation) {
      var _data$offsets = data.offsets,
          reference = _data$offsets.reference,
          popper = _data$offsets.popper;

      var isVertical = ['bottom', 'top'].indexOf(basePlacement) !== -1;
      var side = isVertical ? 'left' : 'top';
      var measurement = isVertical ? 'width' : 'height';

      var shiftOffsets = {
        start: defineProperty({}, side, reference[side]),
        end: defineProperty({}, side, reference[side] + reference[measurement] - popper[measurement])
      };

      data.offsets.popper = _extends$1({}, popper, shiftOffsets[shiftvariation]);
    }

    return data;
  }

  /**
   * @function
   * @memberof Modifiers
   * @argument {Object} data - The data object generated by update method
   * @argument {Object} options - Modifiers configuration and options
   * @returns {Object} The data object, properly modified
   */
  function hide(data) {
    if (!isModifierRequired(data.instance.modifiers, 'hide', 'preventOverflow')) {
      return data;
    }

    var refRect = data.offsets.reference;
    var bound = find$1(data.instance.modifiers, function (modifier) {
      return modifier.name === 'preventOverflow';
    }).boundaries;

    if (refRect.bottom < bound.top || refRect.left > bound.right || refRect.top > bound.bottom || refRect.right < bound.left) {
      // Avoid unnecessary DOM access if visibility hasn't changed
      if (data.hide === true) {
        return data;
      }

      data.hide = true;
      data.attributes['x-out-of-boundaries'] = '';
    } else {
      // Avoid unnecessary DOM access if visibility hasn't changed
      if (data.hide === false) {
        return data;
      }

      data.hide = false;
      data.attributes['x-out-of-boundaries'] = false;
    }

    return data;
  }

  /**
   * @function
   * @memberof Modifiers
   * @argument {Object} data - The data object generated by `update` method
   * @argument {Object} options - Modifiers configuration and options
   * @returns {Object} The data object, properly modified
   */
  function inner(data) {
    var placement = data.placement;
    var basePlacement = placement.split('-')[0];
    var _data$offsets = data.offsets,
        popper = _data$offsets.popper,
        reference = _data$offsets.reference;

    var isHoriz = ['left', 'right'].indexOf(basePlacement) !== -1;

    var subtractLength = ['top', 'left'].indexOf(basePlacement) === -1;

    popper[isHoriz ? 'left' : 'top'] = reference[basePlacement] - (subtractLength ? popper[isHoriz ? 'width' : 'height'] : 0);

    data.placement = getOppositePlacement(placement);
    data.offsets.popper = getClientRect(popper);

    return data;
  }

  /**
   * Modifier function, each modifier can have a function of this type assigned
   * to its `fn` property.<br />
   * These functions will be called on each update, this means that you must
   * make sure they are performant enough to avoid performance bottlenecks.
   *
   * @function ModifierFn
   * @argument {dataObject} data - The data object generated by `update` method
   * @argument {Object} options - Modifiers configuration and options
   * @returns {dataObject} The data object, properly modified
   */

  /**
   * Modifiers are plugins used to alter the behavior of your poppers.<br />
   * Popper.js uses a set of 9 modifiers to provide all the basic functionalities
   * needed by the library.
   *
   * Usually you don't want to override the `order`, `fn` and `onLoad` props.
   * All the other properties are configurations that could be tweaked.
   * @namespace modifiers
   */
  var modifiers = {
    /**
     * Modifier used to shift the popper on the start or end of its reference
     * element.<br />
     * It will read the variation of the `placement` property.<br />
     * It can be one either `-end` or `-start`.
     * @memberof modifiers
     * @inner
     */
    shift: {
      /** @prop {number} order=100 - Index used to define the order of execution */
      order: 100,
      /** @prop {Boolean} enabled=true - Whether the modifier is enabled or not */
      enabled: true,
      /** @prop {ModifierFn} */
      fn: shift
    },

    /**
     * The `offset` modifier can shift your popper on both its axis.
     *
     * It accepts the following units:
     * - `px` or unit-less, interpreted as pixels
     * - `%` or `%r`, percentage relative to the length of the reference element
     * - `%p`, percentage relative to the length of the popper element
     * - `vw`, CSS viewport width unit
     * - `vh`, CSS viewport height unit
     *
     * For length is intended the main axis relative to the placement of the popper.<br />
     * This means that if the placement is `top` or `bottom`, the length will be the
     * `width`. In case of `left` or `right`, it will be the `height`.
     *
     * You can provide a single value (as `Number` or `String`), or a pair of values
     * as `String` divided by a comma or one (or more) white spaces.<br />
     * The latter is a deprecated method because it leads to confusion and will be
     * removed in v2.<br />
     * Additionally, it accepts additions and subtractions between different units.
     * Note that multiplications and divisions aren't supported.
     *
     * Valid examples are:
     * ```
     * 10
     * '10%'
     * '10, 10'
     * '10%, 10'
     * '10 + 10%'
     * '10 - 5vh + 3%'
     * '-10px + 5vh, 5px - 6%'
     * ```
     * > **NB**: If you desire to apply offsets to your poppers in a way that may make them overlap
     * > with their reference element, unfortunately, you will have to disable the `flip` modifier.
     * > You can read more on this at this [issue](https://github.com/FezVrasta/popper.js/issues/373).
     *
     * @memberof modifiers
     * @inner
     */
    offset: {
      /** @prop {number} order=200 - Index used to define the order of execution */
      order: 200,
      /** @prop {Boolean} enabled=true - Whether the modifier is enabled or not */
      enabled: true,
      /** @prop {ModifierFn} */
      fn: offset,
      /** @prop {Number|String} offset=0
       * The offset value as described in the modifier description
       */
      offset: 0
    },

    /**
     * Modifier used to prevent the popper from being positioned outside the boundary.
     *
     * A scenario exists where the reference itself is not within the boundaries.<br />
     * We can say it has "escaped the boundaries" — or just "escaped".<br />
     * In this case we need to decide whether the popper should either:
     *
     * - detach from the reference and remain "trapped" in the boundaries, or
     * - if it should ignore the boundary and "escape with its reference"
     *
     * When `escapeWithReference` is set to`true` and reference is completely
     * outside its boundaries, the popper will overflow (or completely leave)
     * the boundaries in order to remain attached to the edge of the reference.
     *
     * @memberof modifiers
     * @inner
     */
    preventOverflow: {
      /** @prop {number} order=300 - Index used to define the order of execution */
      order: 300,
      /** @prop {Boolean} enabled=true - Whether the modifier is enabled or not */
      enabled: true,
      /** @prop {ModifierFn} */
      fn: preventOverflow,
      /**
       * @prop {Array} [priority=['left','right','top','bottom']]
       * Popper will try to prevent overflow following these priorities by default,
       * then, it could overflow on the left and on top of the `boundariesElement`
       */
      priority: ['left', 'right', 'top', 'bottom'],
      /**
       * @prop {number} padding=5
       * Amount of pixel used to define a minimum distance between the boundaries
       * and the popper. This makes sure the popper always has a little padding
       * between the edges of its container
       */
      padding: 5,
      /**
       * @prop {String|HTMLElement} boundariesElement='scrollParent'
       * Boundaries used by the modifier. Can be `scrollParent`, `window`,
       * `viewport` or any DOM element.
       */
      boundariesElement: 'scrollParent'
    },

    /**
     * Modifier used to make sure the reference and its popper stay near each other
     * without leaving any gap between the two. Especially useful when the arrow is
     * enabled and you want to ensure that it points to its reference element.
     * It cares only about the first axis. You can still have poppers with margin
     * between the popper and its reference element.
     * @memberof modifiers
     * @inner
     */
    keepTogether: {
      /** @prop {number} order=400 - Index used to define the order of execution */
      order: 400,
      /** @prop {Boolean} enabled=true - Whether the modifier is enabled or not */
      enabled: true,
      /** @prop {ModifierFn} */
      fn: keepTogether
    },

    /**
     * This modifier is used to move the `arrowElement` of the popper to make
     * sure it is positioned between the reference element and its popper element.
     * It will read the outer size of the `arrowElement` node to detect how many
     * pixels of conjunction are needed.
     *
     * It has no effect if no `arrowElement` is provided.
     * @memberof modifiers
     * @inner
     */
    arrow: {
      /** @prop {number} order=500 - Index used to define the order of execution */
      order: 500,
      /** @prop {Boolean} enabled=true - Whether the modifier is enabled or not */
      enabled: true,
      /** @prop {ModifierFn} */
      fn: arrow,
      /** @prop {String|HTMLElement} element='[x-arrow]' - Selector or node used as arrow */
      element: '[x-arrow]'
    },

    /**
     * Modifier used to flip the popper's placement when it starts to overlap its
     * reference element.
     *
     * Requires the `preventOverflow` modifier before it in order to work.
     *
     * **NOTE:** this modifier will interrupt the current update cycle and will
     * restart it if it detects the need to flip the placement.
     * @memberof modifiers
     * @inner
     */
    flip: {
      /** @prop {number} order=600 - Index used to define the order of execution */
      order: 600,
      /** @prop {Boolean} enabled=true - Whether the modifier is enabled or not */
      enabled: true,
      /** @prop {ModifierFn} */
      fn: flip,
      /**
       * @prop {String|Array} behavior='flip'
       * The behavior used to change the popper's placement. It can be one of
       * `flip`, `clockwise`, `counterclockwise` or an array with a list of valid
       * placements (with optional variations)
       */
      behavior: 'flip',
      /**
       * @prop {number} padding=5
       * The popper will flip if it hits the edges of the `boundariesElement`
       */
      padding: 5,
      /**
       * @prop {String|HTMLElement} boundariesElement='viewport'
       * The element which will define the boundaries of the popper position.
       * The popper will never be placed outside of the defined boundaries
       * (except if `keepTogether` is enabled)
       */
      boundariesElement: 'viewport',
      /**
       * @prop {Boolean} flipVariations=false
       * The popper will switch placement variation between `-start` and `-end` when
       * the reference element overlaps its boundaries.
       *
       * The original placement should have a set variation.
       */
      flipVariations: false,
      /**
       * @prop {Boolean} flipVariationsByContent=false
       * The popper will switch placement variation between `-start` and `-end` when
       * the popper element overlaps its reference boundaries.
       *
       * The original placement should have a set variation.
       */
      flipVariationsByContent: false
    },

    /**
     * Modifier used to make the popper flow toward the inner of the reference element.
     * By default, when this modifier is disabled, the popper will be placed outside
     * the reference element.
     * @memberof modifiers
     * @inner
     */
    inner: {
      /** @prop {number} order=700 - Index used to define the order of execution */
      order: 700,
      /** @prop {Boolean} enabled=false - Whether the modifier is enabled or not */
      enabled: false,
      /** @prop {ModifierFn} */
      fn: inner
    },

    /**
     * Modifier used to hide the popper when its reference element is outside of the
     * popper boundaries. It will set a `x-out-of-boundaries` attribute which can
     * be used to hide with a CSS selector the popper when its reference is
     * out of boundaries.
     *
     * Requires the `preventOverflow` modifier before it in order to work.
     * @memberof modifiers
     * @inner
     */
    hide: {
      /** @prop {number} order=800 - Index used to define the order of execution */
      order: 800,
      /** @prop {Boolean} enabled=true - Whether the modifier is enabled or not */
      enabled: true,
      /** @prop {ModifierFn} */
      fn: hide
    },

    /**
     * Computes the style that will be applied to the popper element to gets
     * properly positioned.
     *
     * Note that this modifier will not touch the DOM, it just prepares the styles
     * so that `applyStyle` modifier can apply it. This separation is useful
     * in case you need to replace `applyStyle` with a custom implementation.
     *
     * This modifier has `850` as `order` value to maintain backward compatibility
     * with previous versions of Popper.js. Expect the modifiers ordering method
     * to change in future major versions of the library.
     *
     * @memberof modifiers
     * @inner
     */
    computeStyle: {
      /** @prop {number} order=850 - Index used to define the order of execution */
      order: 850,
      /** @prop {Boolean} enabled=true - Whether the modifier is enabled or not */
      enabled: true,
      /** @prop {ModifierFn} */
      fn: computeStyle,
      /**
       * @prop {Boolean} gpuAcceleration=true
       * If true, it uses the CSS 3D transformation to position the popper.
       * Otherwise, it will use the `top` and `left` properties
       */
      gpuAcceleration: true,
      /**
       * @prop {string} [x='bottom']
       * Where to anchor the X axis (`bottom` or `top`). AKA X offset origin.
       * Change this if your popper should grow in a direction different from `bottom`
       */
      x: 'bottom',
      /**
       * @prop {string} [x='left']
       * Where to anchor the Y axis (`left` or `right`). AKA Y offset origin.
       * Change this if your popper should grow in a direction different from `right`
       */
      y: 'right'
    },

    /**
     * Applies the computed styles to the popper element.
     *
     * All the DOM manipulations are limited to this modifier. This is useful in case
     * you want to integrate Popper.js inside a framework or view library and you
     * want to delegate all the DOM manipulations to it.
     *
     * Note that if you disable this modifier, you must make sure the popper element
     * has its position set to `absolute` before Popper.js can do its work!
     *
     * Just disable this modifier and define your own to achieve the desired effect.
     *
     * @memberof modifiers
     * @inner
     */
    applyStyle: {
      /** @prop {number} order=900 - Index used to define the order of execution */
      order: 900,
      /** @prop {Boolean} enabled=true - Whether the modifier is enabled or not */
      enabled: true,
      /** @prop {ModifierFn} */
      fn: applyStyle,
      /** @prop {Function} */
      onLoad: applyStyleOnLoad,
      /**
       * @deprecated since version 1.10.0, the property moved to `computeStyle` modifier
       * @prop {Boolean} gpuAcceleration=true
       * If true, it uses the CSS 3D transformation to position the popper.
       * Otherwise, it will use the `top` and `left` properties
       */
      gpuAcceleration: undefined
    }
  };

  /**
   * The `dataObject` is an object containing all the information used by Popper.js.
   * This object is passed to modifiers and to the `onCreate` and `onUpdate` callbacks.
   * @name dataObject
   * @property {Object} data.instance The Popper.js instance
   * @property {String} data.placement Placement applied to popper
   * @property {String} data.originalPlacement Placement originally defined on init
   * @property {Boolean} data.flipped True if popper has been flipped by flip modifier
   * @property {Boolean} data.hide True if the reference element is out of boundaries, useful to know when to hide the popper
   * @property {HTMLElement} data.arrowElement Node used as arrow by arrow modifier
   * @property {Object} data.styles Any CSS property defined here will be applied to the popper. It expects the JavaScript nomenclature (eg. `marginBottom`)
   * @property {Object} data.arrowStyles Any CSS property defined here will be applied to the popper arrow. It expects the JavaScript nomenclature (eg. `marginBottom`)
   * @property {Object} data.boundaries Offsets of the popper boundaries
   * @property {Object} data.offsets The measurements of popper, reference and arrow elements
   * @property {Object} data.offsets.popper `top`, `left`, `width`, `height` values
   * @property {Object} data.offsets.reference `top`, `left`, `width`, `height` values
   * @property {Object} data.offsets.arrow] `top` and `left` offsets, only one of them will be different from 0
   */

  /**
   * Default options provided to Popper.js constructor.<br />
   * These can be overridden using the `options` argument of Popper.js.<br />
   * To override an option, simply pass an object with the same
   * structure of the `options` object, as the 3rd argument. For example:
   * ```
   * new Popper(ref, pop, {
   *   modifiers: {
   *     preventOverflow: { enabled: false }
   *   }
   * })
   * ```
   * @type {Object}
   * @static
   * @memberof Popper
   */
  var Defaults = {
    /**
     * Popper's placement.
     * @prop {Popper.placements} placement='bottom'
     */
    placement: 'bottom',

    /**
     * Set this to true if you want popper to position it self in 'fixed' mode
     * @prop {Boolean} positionFixed=false
     */
    positionFixed: false,

    /**
     * Whether events (resize, scroll) are initially enabled.
     * @prop {Boolean} eventsEnabled=true
     */
    eventsEnabled: true,

    /**
     * Set to true if you want to automatically remove the popper when
     * you call the `destroy` method.
     * @prop {Boolean} removeOnDestroy=false
     */
    removeOnDestroy: false,

    /**
     * Callback called when the popper is created.<br />
     * By default, it is set to no-op.<br />
     * Access Popper.js instance with `data.instance`.
     * @prop {onCreate}
     */
    onCreate: function onCreate() {},

    /**
     * Callback called when the popper is updated. This callback is not called
     * on the initialization/creation of the popper, but only on subsequent
     * updates.<br />
     * By default, it is set to no-op.<br />
     * Access Popper.js instance with `data.instance`.
     * @prop {onUpdate}
     */
    onUpdate: function onUpdate() {},

    /**
     * List of modifiers used to modify the offsets before they are applied to the popper.
     * They provide most of the functionalities of Popper.js.
     * @prop {modifiers}
     */
    modifiers: modifiers
  };

  /**
   * @callback onCreate
   * @param {dataObject} data
   */

  /**
   * @callback onUpdate
   * @param {dataObject} data
   */

  // Utils
  // Methods
  var Popper = function () {
    /**
     * Creates a new Popper.js instance.
     * @class Popper
     * @param {Element|referenceObject} reference - The reference element used to position the popper
     * @param {Element} popper - The HTML / XML element used as the popper
     * @param {Object} options - Your custom options to override the ones defined in [Defaults](#defaults)
     * @return {Object} instance - The generated Popper.js instance
     */
    function Popper(reference, popper) {
      var _this = this;

      var options = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : {};
      classCallCheck(this, Popper);

      this.scheduleUpdate = function () {
        return requestAnimationFrame(_this.update);
      };

      // make update() debounced, so that it only runs at most once-per-tick
      this.update = debounce(this.update.bind(this));

      // with {} we create a new object with the options inside it
      this.options = _extends$1({}, Popper.Defaults, options);

      // init state
      this.state = {
        isDestroyed: false,
        isCreated: false,
        scrollParents: []
      };

      // get reference and popper elements (allow jQuery wrappers)
      this.reference = reference && reference.jquery ? reference[0] : reference;
      this.popper = popper && popper.jquery ? popper[0] : popper;

      // Deep merge modifiers options
      this.options.modifiers = {};
      Object.keys(_extends$1({}, Popper.Defaults.modifiers, options.modifiers)).forEach(function (name) {
        _this.options.modifiers[name] = _extends$1({}, Popper.Defaults.modifiers[name] || {}, options.modifiers ? options.modifiers[name] : {});
      });

      // Refactoring modifiers' list (Object => Array)
      this.modifiers = Object.keys(this.options.modifiers).map(function (name) {
        return _extends$1({
          name: name
        }, _this.options.modifiers[name]);
      })
      // sort the modifiers by order
      .sort(function (a, b) {
        return a.order - b.order;
      });

      // modifiers have the ability to execute arbitrary code when Popper.js get inited
      // such code is executed in the same order of its modifier
      // they could add new properties to their options configuration
      // BE AWARE: don't add options to `options.modifiers.name` but to `modifierOptions`!
      this.modifiers.forEach(function (modifierOptions) {
        if (modifierOptions.enabled && isFunction(modifierOptions.onLoad)) {
          modifierOptions.onLoad(_this.reference, _this.popper, _this.options, modifierOptions, _this.state);
        }
      });

      // fire the first update to position the popper in the right place
      this.update();

      var eventsEnabled = this.options.eventsEnabled;
      if (eventsEnabled) {
        // setup event listeners, they will take care of update the position in specific situations
        this.enableEventListeners();
      }

      this.state.eventsEnabled = eventsEnabled;
    }

    // We can't use class properties because they don't get listed in the
    // class prototype and break stuff like Sinon stubs


    createClass(Popper, [{
      key: 'update',
      value: function update$$1() {
        return update.call(this);
      }
    }, {
      key: 'destroy',
      value: function destroy$$1() {
        return destroy.call(this);
      }
    }, {
      key: 'enableEventListeners',
      value: function enableEventListeners$$1() {
        return enableEventListeners.call(this);
      }
    }, {
      key: 'disableEventListeners',
      value: function disableEventListeners$$1() {
        return disableEventListeners.call(this);
      }

      /**
       * Schedules an update. It will run on the next UI update available.
       * @method scheduleUpdate
       * @memberof Popper
       */


      /**
       * Collection of utilities useful when writing custom modifiers.
       * Starting from version 1.7, this method is available only if you
       * include `popper-utils.js` before `popper.js`.
       *
       * **DEPRECATION**: This way to access PopperUtils is deprecated
       * and will be removed in v2! Use the PopperUtils module directly instead.
       * Due to the high instability of the methods contained in Utils, we can't
       * guarantee them to follow semver. Use them at your own risk!
       * @static
       * @private
       * @type {Object}
       * @deprecated since version 1.8
       * @member Utils
       * @memberof Popper
       */

    }]);
    return Popper;
  }();

  /**
   * The `referenceObject` is an object that provides an interface compatible with Popper.js
   * and lets you use it as replacement of a real DOM node.<br />
   * You can use this method to position a popper relatively to a set of coordinates
   * in case you don't have a DOM node to use as reference.
   *
   * ```
   * new Popper(referenceObject, popperNode);
   * ```
   *
   * NB: This feature isn't supported in Internet Explorer 10.
   * @name referenceObject
   * @property {Function} data.getBoundingClientRect
   * A function that returns a set of coordinates compatible with the native `getBoundingClientRect` method.
   * @property {number} data.clientWidth
   * An ES6 getter that will return the width of the virtual reference element.
   * @property {number} data.clientHeight
   * An ES6 getter that will return the height of the virtual reference element.
   */


  Popper.Utils = (typeof window !== 'undefined' ? window : global).PopperUtils;
  Popper.placements = placements;
  Popper.Defaults = Defaults;

  /**
   * ------------------------------------------------------------------------
   * Constants
   * ------------------------------------------------------------------------
   */

  var NAME$4 = 'dropdown';
  var VERSION$4 = '5.0.0-alpha2';
  var DATA_KEY$4 = 'bs.dropdown';
  var EVENT_KEY$4 = "." + DATA_KEY$4;
  var DATA_API_KEY$4 = '.data-api';
  var ESCAPE_KEY = 'Escape';
  var SPACE_KEY = 'Space';
  var TAB_KEY = 'Tab';
  var ARROW_UP_KEY = 'ArrowUp';
  var ARROW_DOWN_KEY = 'ArrowDown';
  var RIGHT_MOUSE_BUTTON = 2; // MouseEvent.button value for the secondary button, usually the right button

  var REGEXP_KEYDOWN = new RegExp(ARROW_UP_KEY + "|" + ARROW_DOWN_KEY + "|" + ESCAPE_KEY);
  var EVENT_HIDE$1 = "hide" + EVENT_KEY$4;
  var EVENT_HIDDEN$1 = "hidden" + EVENT_KEY$4;
  var EVENT_SHOW$1 = "show" + EVENT_KEY$4;
  var EVENT_SHOWN$1 = "shown" + EVENT_KEY$4;
  var EVENT_CLICK = "click" + EVENT_KEY$4;
  var EVENT_CLICK_DATA_API$4 = "click" + EVENT_KEY$4 + DATA_API_KEY$4;
  var EVENT_KEYDOWN_DATA_API = "keydown" + EVENT_KEY$4 + DATA_API_KEY$4;
  var EVENT_KEYUP_DATA_API = "keyup" + EVENT_KEY$4 + DATA_API_KEY$4;
  var CLASS_NAME_DISABLED = 'disabled';
  var CLASS_NAME_SHOW$1 = 'show';
  var CLASS_NAME_DROPUP = 'dropup';
  var CLASS_NAME_DROPRIGHT = 'dropright';
  var CLASS_NAME_DROPLEFT = 'dropleft';
  var CLASS_NAME_MENURIGHT = 'dropdown-menu-right';
  var CLASS_NAME_NAVBAR = 'navbar';
  var CLASS_NAME_POSITION_STATIC = 'position-static';
  var SELECTOR_DATA_TOGGLE$2 = '[data-toggle="dropdown"]';
  var SELECTOR_FORM_CHILD = '.dropdown form';
  var SELECTOR_MENU = '.dropdown-menu';
  var SELECTOR_NAVBAR_NAV = '.navbar-nav';
  var SELECTOR_VISIBLE_ITEMS = '.dropdown-menu .dropdown-item:not(.disabled):not(:disabled)';
  var PLACEMENT_TOP = 'top-start';
  var PLACEMENT_TOPEND = 'top-end';
  var PLACEMENT_BOTTOM = 'bottom-start';
  var PLACEMENT_BOTTOMEND = 'bottom-end';
  var PLACEMENT_RIGHT = 'right-start';
  var PLACEMENT_LEFT = 'left-start';
  var Default$2 = {
    offset: 0,
    flip: true,
    boundary: 'scrollParent',
    reference: 'toggle',
    display: 'dynamic',
    popperConfig: null
  };
  var DefaultType$2 = {
    offset: '(number|string|function)',
    flip: 'boolean',
    boundary: '(string|element)',
    reference: '(string|element)',
    display: 'string',
    popperConfig: '(null|object)'
  };
  /**
   * ------------------------------------------------------------------------
   * Class Definition
   * ------------------------------------------------------------------------
   */

  var Dropdown = /*#__PURE__*/function () {
    function Dropdown(element, config) {
      this._element = element;
      this._popper = null;
      this._config = this._getConfig(config);
      this._menu = this._getMenuElement();
      this._inNavbar = this._detectNavbar();

      this._addEventListeners();

      Data.setData(element, DATA_KEY$4, this);
    } // Getters


    var _proto = Dropdown.prototype;

    // Public
    _proto.toggle = function toggle() {
      if (this._element.disabled || this._element.classList.contains(CLASS_NAME_DISABLED)) {
        return;
      }

      var isActive = this._element.classList.contains(CLASS_NAME_SHOW$1);

      Dropdown.clearMenus();

      if (isActive) {
        return;
      }

      this.show();
    };

    _proto.show = function show() {
      if (this._element.disabled || this._element.classList.contains(CLASS_NAME_DISABLED) || this._menu.classList.contains(CLASS_NAME_SHOW$1)) {
        return;
      }

      var parent = Dropdown.getParentFromElement(this._element);
      var relatedTarget = {
        relatedTarget: this._element
      };
      var showEvent = EventHandler.trigger(this._element, EVENT_SHOW$1, relatedTarget);

      if (showEvent.defaultPrevented) {
        return;
      } // Disable totally Popper.js for Dropdown in Navbar


      if (!this._inNavbar) {
        if (typeof Popper === 'undefined') {
          throw new TypeError('Bootstrap\'s dropdowns require Popper.js (https://popper.js.org)');
        }

        var referenceElement = this._element;

        if (this._config.reference === 'parent') {
          referenceElement = parent;
        } else if (isElement(this._config.reference)) {
          referenceElement = this._config.reference; // Check if it's jQuery element

          if (typeof this._config.reference.jquery !== 'undefined') {
            referenceElement = this._config.reference[0];
          }
        } // If boundary is not `scrollParent`, then set position to `static`
        // to allow the menu to "escape" the scroll parent's boundaries
        // https://github.com/twbs/bootstrap/issues/24251


        if (this._config.boundary !== 'scrollParent') {
          parent.classList.add(CLASS_NAME_POSITION_STATIC);
        }

        this._popper = new Popper(referenceElement, this._menu, this._getPopperConfig());
      } // If this is a touch-enabled device we add extra
      // empty mouseover listeners to the body's immediate children;
      // only needed because of broken event delegation on iOS
      // https://www.quirksmode.org/blog/archives/2014/02/mouse_event_bub.html


      if ('ontouchstart' in document.documentElement && !parent.closest(SELECTOR_NAVBAR_NAV)) {
        var _ref;

        (_ref = []).concat.apply(_ref, document.body.children).forEach(function (elem) {
          return EventHandler.on(elem, 'mouseover', null, noop());
        });
      }

      this._element.focus();

      this._element.setAttribute('aria-expanded', true);

      Manipulator.toggleClass(this._menu, CLASS_NAME_SHOW$1);
      Manipulator.toggleClass(this._element, CLASS_NAME_SHOW$1);
      EventHandler.trigger(parent, EVENT_SHOWN$1, relatedTarget);
    };

    _proto.hide = function hide() {
      if (this._element.disabled || this._element.classList.contains(CLASS_NAME_DISABLED) || !this._menu.classList.contains(CLASS_NAME_SHOW$1)) {
        return;
      }

      var parent = Dropdown.getParentFromElement(this._element);
      var relatedTarget = {
        relatedTarget: this._element
      };
      var hideEvent = EventHandler.trigger(parent, EVENT_HIDE$1, relatedTarget);

      if (hideEvent.defaultPrevented) {
        return;
      }

      if (this._popper) {
        this._popper.destroy();
      }

      Manipulator.toggleClass(this._menu, CLASS_NAME_SHOW$1);
      Manipulator.toggleClass(this._element, CLASS_NAME_SHOW$1);
      EventHandler.trigger(parent, EVENT_HIDDEN$1, relatedTarget);
    };

    _proto.dispose = function dispose() {
      Data.removeData(this._element, DATA_KEY$4);
      EventHandler.off(this._element, EVENT_KEY$4);
      this._element = null;
      this._menu = null;

      if (this._popper) {
        this._popper.destroy();

        this._popper = null;
      }
    };

    _proto.update = function update() {
      this._inNavbar = this._detectNavbar();

      if (this._popper) {
        this._popper.scheduleUpdate();
      }
    } // Private
    ;

    _proto._addEventListeners = function _addEventListeners() {
      var _this = this;

      EventHandler.on(this._element, EVENT_CLICK, function (event) {
        event.preventDefault();
        event.stopPropagation();

        _this.toggle();
      });
    };

    _proto._getConfig = function _getConfig(config) {
      config = _extends({}, this.constructor.Default, Manipulator.getDataAttributes(this._element), config);
      typeCheckConfig(NAME$4, config, this.constructor.DefaultType);
      return config;
    };

    _proto._getMenuElement = function _getMenuElement() {
      return SelectorEngine.next(this._element, SELECTOR_MENU)[0];
    };

    _proto._getPlacement = function _getPlacement() {
      var parentDropdown = this._element.parentNode;
      var placement = PLACEMENT_BOTTOM; // Handle dropup

      if (parentDropdown.classList.contains(CLASS_NAME_DROPUP)) {
        placement = PLACEMENT_TOP;

        if (this._menu.classList.contains(CLASS_NAME_MENURIGHT)) {
          placement = PLACEMENT_TOPEND;
        }
      } else if (parentDropdown.classList.contains(CLASS_NAME_DROPRIGHT)) {
        placement = PLACEMENT_RIGHT;
      } else if (parentDropdown.classList.contains(CLASS_NAME_DROPLEFT)) {
        placement = PLACEMENT_LEFT;
      } else if (this._menu.classList.contains(CLASS_NAME_MENURIGHT)) {
        placement = PLACEMENT_BOTTOMEND;
      }

      return placement;
    };

    _proto._detectNavbar = function _detectNavbar() {
      return Boolean(this._element.closest("." + CLASS_NAME_NAVBAR));
    };

    _proto._getOffset = function _getOffset() {
      var _this2 = this;

      var offset = {};

      if (typeof this._config.offset === 'function') {
        offset.fn = function (data) {
          data.offsets = _extends({}, data.offsets, _this2._config.offset(data.offsets, _this2._element) || {});
          return data;
        };
      } else {
        offset.offset = this._config.offset;
      }

      return offset;
    };

    _proto._getPopperConfig = function _getPopperConfig() {
      var popperConfig = {
        placement: this._getPlacement(),
        modifiers: {
          offset: this._getOffset(),
          flip: {
            enabled: this._config.flip
          },
          preventOverflow: {
            boundariesElement: this._config.boundary
          }
        }
      }; // Disable Popper.js if we have a static display

      if (this._config.display === 'static') {
        popperConfig.modifiers.applyStyle = {
          enabled: false
        };
      }

      return _extends({}, popperConfig, this._config.popperConfig);
    } // Static
    ;

    Dropdown.dropdownInterface = function dropdownInterface(element, config) {
      var data = Data.getData(element, DATA_KEY$4);

      var _config = typeof config === 'object' ? config : null;

      if (!data) {
        data = new Dropdown(element, _config);
      }

      if (typeof config === 'string') {
        if (typeof data[config] === 'undefined') {
          throw new TypeError("No method named \"" + config + "\"");
        }

        data[config]();
      }