@seznam/szn-select/szn-select.bundle-full.ce.js

Accessible HTML selectbox with customizable UI. Based on web components and easy to integrate with various frameworks like React or Angular.

'use strict';

(global => {
  const SznElements = global.SznElements = global.SznElements || {};
  /**
   * @typedef {{width: number, height: number}} ContentDimensions
   */

  /**
   * @typedef {{screenX: number, screenY: number, x: number, y: number, width: number, height: number}} TetherBounds
   */

  const CSS_STYLES = `
    szn-tethered {
      display: block;

      position: absolute;
      left: 0;
      top: 0;

      width: 0;
      height: 0;

      transform: translate(0, 0);
    }

    szn-tethered > [data-szn-tethered--content] {
        position: absolute;
        left: 0;
        top: 0;
    }

    szn-tethered[data-horizontal-align='right'] > [data-szn-tethered--content] {
        left: auto;
        right: 0;
    }

    szn-tethered[data-vertical-align='top'] > [data-szn-tethered--content] {
        top: auto;
        bottom: 0;
    }
  `;
  const HORIZONTAL_ALIGN = {
    LEFT: 'HORIZONTAL_ALIGN.LEFT',
    RIGHT: 'HORIZONTAL_ALIGN.RIGHT'
  };
  const VERTICAL_ALIGN = {
    TOP: 'VERTICAL_ALIGN.TOP',
    BOTTOM: 'VERTICAL_ALIGN.BOTTOM'
  };
  const MIN_BOTTOM_SPACE = 160; // px

  const OBSERVED_DOM_EVENTS = ['resize', 'scroll', 'wheel', 'touchmove'];

  if (Object.freeze) {
    Object.freeze(HORIZONTAL_ALIGN);
    Object.freeze(VERTICAL_ALIGN);
  }

  let transformsSupported = null;
  /**
   * The <code>szn-tethered</code> element is used to tether the on-screen position of content to another element
   * located elsewhere in the document (i.e. when such positioning is not feasible through CSS alone).
   */

  SznElements['szn-tethered'] = class SznTethered {
    constructor(rootElement) {
      if (transformsSupported === null) {
        transformsSupported = 'transform' in rootElement.style;
      }

      rootElement.HORIZONTAL_ALIGN = HORIZONTAL_ALIGN;
      rootElement.VERTICAL_ALIGN = VERTICAL_ALIGN;

      rootElement.setTether = tether => this.setTether(tether);

      rootElement.updatePosition = () => this.updatePosition();

      if (!rootElement.hasOwnProperty('horizontalAlign')) {
        Object.defineProperty(rootElement, 'horizontalAlign', {
          get: () => rootElement._broker.horizontalAlignment
        });
      }

      if (!rootElement.hasOwnProperty('verticalAlignment')) {
        Object.defineProperty(rootElement, 'verticalAlignment', {
          get: () => rootElement._broker.verticalAlignment
        });
      }

      if (!rootElement.hasOwnProperty('minBottomSpace')) {
        Object.defineProperty(rootElement, 'minBottomSpace', {
          get: () => rootElement._broker.minBottomSpace,
          set: value => {
            rootElement._broker.minBottomSpace = value;
          }
        });
      }

      rootElement.onVerticalAlignmentChange = null;
      rootElement.onHorizontalAlignmentChange = null;
      /**
       * The currently used horizontal alignment of the content to the tethering element.
       *
       * @type {string}
       */

      this.horizontalAlignment = HORIZONTAL_ALIGN.LEFT;
      /**
       * The currently used vertical alignment of the content to the tethering element.
       *
       * @type {string}
       */

      this.verticalAlignment = VERTICAL_ALIGN.BOTTOM;
      /**
       * The minimum number of pixels that must be available below the current tethering element in the viewport for
       * the content to be tethered to the bottom edge of the tethering element. If there is less space available, the
       * content will be tethered to the top edge of the tethering element.
       *
       * @type {number}
       */

      this.minBottomSpace = MIN_BOTTOM_SPACE;
      /**
       * The szn-tethered element itself (the DOM element instance).
       */

      this._root = rootElement;
      /**
       * The current tethering element.
       *
       * @type {?Element}
       */

      this._tether = null;
      /**
       * Whether or not this szn-tethered element is currently mounted into the document.
       *
       * @type {boolean}
       */

      this._mounted = false;
      /**
       * The previously set horizontal alignment of the tethered content to the tether, before updating the alignment
       * data attributes of the szn-tethered element.
       *
       * @type {string}
       */

      this._lastHorizontalAlignment = null;
      /**
       * The previously set vertical alignment of the tethered content to the tether, before updating the alignment
       * data attributes of the szn-tethered element.
       *
       * @type {string}
       */

      this._lastVerticalAlignment = null;
      SznElements.injectStyles(CSS_STYLES, 'szn-tethered');
    }

    onMount() {
      for (const eventType of OBSERVED_DOM_EVENTS) {
        addEventListener(eventType, this._root.updatePosition);
      }

      this._mounted = true;
      this.updatePosition();
    }

    onUnmount() {
      for (const eventType of OBSERVED_DOM_EVENTS) {
        removeEventListener(eventType, this._root.updatePosition);
      }

      this._mounted = false;
    }
    /**
     * Sets the element to which this element will be tethered.
     *
     * @param {Element} tether The element to which this szn-tethered element should be tethered.
     */


    setTether(tether) {
      if (tether === this._tether) {
        return;
      }

      this._tether = tether;
      this.updatePosition();
    }
    /**
     * Updates the location and alignment of the tethered content to the tethering element. The method may be invoked
     * manually if updating the location of the tethered content is needed for any reason.
     *
     * Note that this method is automatically invoked whenever any of the following events occur on the page: resize,
     * scroll, wheel, touchmove.
     *
     * This method has no effect if the szn-tethered element is unmounted or no tethering element is currently set.
     */


    updatePosition() {
      if (!this._mounted || !this._tether) {
        return;
      }

      const tetherBounds = getTetherBounds(this._tether);
      const contentSize = getContentDimensions(this);
      const viewportWidth = document.documentElement.clientWidth; // window.innerWidth - scrollbars
      // Lets hope the document element (<html>) is at least 100vh high - which it usually is.

      const viewportHeight = Math.min(document.documentElement.clientHeight, // window.innerHeight - scrollbars
      window.innerHeight);
      const lastHorizontalAlignment = this.horizontalAlignment;
      const lastVerticalAlignment = this.verticalAlignment;

      if (tetherBounds.screenX + contentSize.width > viewportWidth && tetherBounds.screenX + tetherBounds.width - contentSize.width >= 0) {
        this.horizontalAlignment = HORIZONTAL_ALIGN.RIGHT;
      } else {
        this.horizontalAlignment = HORIZONTAL_ALIGN.LEFT;
      }

      if (viewportHeight - (tetherBounds.screenY + tetherBounds.height) < this.minBottomSpace) {
        this.verticalAlignment = VERTICAL_ALIGN.TOP;
      } else {
        this.verticalAlignment = VERTICAL_ALIGN.BOTTOM;
      }

      updateAttributes(this);
      updatePosition(this, tetherBounds);

      if (this.horizontalAlignment !== lastHorizontalAlignment && this._root.onHorizontalAlignmentChange) {
        this._root.onHorizontalAlignmentChange(this.horizontalAlignment);
      }

      if (this.verticalAlignment !== lastVerticalAlignment && this._root.onVerticalAlignmentChange) {
        this._root.onVerticalAlignmentChange(this.verticalAlignment);
      }
    }

  };
  /**
   * Updates the position of the szn-tethered element according to the current tethering alignment and the provided
   * bounds of the tethering element.
   *
   * @param {SznElements.SznTethered} instance The szn-tethered element instance.
   * @param {TetherBounds} tetherBounds The bounds (location and size) of the tethering element.
   */

  function updatePosition(instance, tetherBounds) {
    const x = tetherBounds.x + (instance.horizontalAlignment === HORIZONTAL_ALIGN.LEFT ? 0 : tetherBounds.width);
    const y = tetherBounds.y + (instance.verticalAlignment === VERTICAL_ALIGN.TOP ? 0 : tetherBounds.height);

    if (transformsSupported) {
      instance._root.style.transform = `translate(${x}px, ${y}px)`;
    } else {
      instance._root.style.left = `${x}px`;
      instance._root.style.top = `${y}px`;
    }
  }
  /**
   * Updates the attributes on the szn-tethered element reporting the current alignment to the tethering element.
   *
   * @param {SznElements.SznTethered} instance The szn-tethered element instance.
   */


  function updateAttributes(instance) {
    if (instance.horizontalAlignment !== instance._lastHorizontalAlignment) {
      const horizontalAlignment = instance.horizontalAlignment === HORIZONTAL_ALIGN.LEFT ? 'left' : 'right';

      instance._root.setAttribute('data-horizontal-align', horizontalAlignment);

      instance._lastHorizontalAlignment = instance.horizontalAlignment;
    }

    if (instance.verticalAlignment !== instance._lastVerticalAlignment) {
      const verticalAlignment = instance.verticalAlignment === VERTICAL_ALIGN.TOP ? 'top' : 'bottom';

      instance._root.setAttribute('data-vertical-align', verticalAlignment);

      instance._lastVerticalAlignment = instance.verticalAlignment;
    }
  }
  /**
   * Calculates and returns both the on-screen and on-page location and dimensions of the provided tether element.
   *
   * @param {Element} tether The tethering element.
   * @return {TetherBounds} The on-screen and on-page location and dimensions of the element.
   */


  function getTetherBounds(tether) {
    const bounds = tether.getBoundingClientRect();
    const width = bounds.width;
    const height = bounds.height;
    let x = 0;
    let y = 0;
    let tetherOffsetContainer = tether;

    while (tetherOffsetContainer) {
      x += tetherOffsetContainer.offsetLeft;
      y += tetherOffsetContainer.offsetTop;
      tetherOffsetContainer = tetherOffsetContainer.offsetParent;
    }

    return {
      screenX: bounds.left,
      screenY: bounds.top,
      x,
      y,
      width,
      height
    };
  }
  /**
   * Returns the dimensions of the content of the provided szn-tethered element.
   *
   * @param {SznElements.SznTethered} instance The instance of the szn-tethered element.
   * @return {ContentDimensions} The dimensions of the tethered content.
   */


  function getContentDimensions(instance) {
    const contentElement = instance._root.firstElementChild;

    if (!contentElement) {
      return {
        width: 0,
        height: 0
      };
    }

    let width;
    let height;

    if (window.devicePixelRatio > 1) {
      // This is much less performant, so we use in only on HiDPi displays
      const bounds = contentElement.getBoundingClientRect();
      width = bounds.width;
      height = bounds.height;
    } else {
      width = contentElement.scrollWidth;
      height = contentElement.scrollHeight;
    }

    return {
      width,
      height
    };
  }

  if (SznElements.init) {
    SznElements.init();
  }
})(self);
;
'use strict';

(global => {
  const SznElements = global.SznElements = global.SznElements || {};
  const CSS_STYLES = `
szn-select--button{display:block;position:relative;box-sizing:border-box;border:1px solid #ccc;border:var(--szn-select--button--border-width,1px) solid var(--szn-select--button--border-color,#ccc);border-radius:4px;border-radius:var(--szn-select--button--border-radius,4px);width:100%;height:100%;line-height:30px;line-height:calc(var(--szn-select--button--height-px, 32px) - 2 * var(--szn-select--button--border-width, 1px));line-height:calc(2em - 2 * 1px);line-height:calc(var(--szn-select--button--height, 2em) - 2 * var(--szn-select--button--border-width, 1px));color:#000;color:var(--szn-select--button--text-color,#000);background:#fff;background:var(--szn-select--button--background-color,#fff);cursor:pointer;user-select:none;-moz-user-select:none}szn-select--button[data-szn-select--button--open]{border-radius:4px 4px 0 0;border-radius:var(--szn-select--button--border-radius,4px) var(--szn-select--button--border-radius,4px) 0 0}szn-select--button[data-szn-select--button--open-at-top]{border-radius:0 0 4px 4px;border-radius:0 0 var(--szn-select--button--border-radius,4px) var(--szn-select--button--border-radius,4px)}szn-select--button[disabled]{color:#ccc;color:var(--szn-select--button--disabled-text-color,#ccc);cursor:default}szn-select--button [data-szn-select--button--label]{display:block;box-sizing:border-box;border-right:2em solid transparent;border-right:var(--szn-select--button--mark-width,2em) transparent solid;padding:0 5px 0 12px;padding:var(--szn-select--button--padding,0 5px 0 12px);width:100%;height:100%;overflow:hidden;white-space:nowrap;text-overflow:ellipsis}szn-select--button [data-szn-select--button--mark]{display:block;position:absolute;right:0;top:0;width:2em;width:var(--szn-select--button--mark-width,2em);height:100%;text-align:center}szn-select--button [data-szn-select--button--mark]:after{display:inline;content:"▼";content:var(--szn-select--button--icon-closed,"▼")}szn-select--button[data-szn-select--button--open] [data-szn-select--button--mark]:after{content:"▲";content:var(--szn-select--button--icon-opened,"▲")}
  `;
  const OPENING_POSITION = {
    UP: 'OPENING_POSITION.UP',
    DOWN: 'OPENING_POSITION.DOWN'
  };

  if (Object.freeze) {
    Object.freeze(OPENING_POSITION);
  }

  SznElements['szn-select--button'] = class SznSelectButton {
    constructor(rootElement) {
      this.OPENING_POSITION = OPENING_POSITION;
      this._root = rootElement;
      this._select = null;
      this._label = null;
      this._observer = new MutationObserver(() => {
        updateLabel(this);
        updateDisabledStatus(this);
      });
      rootElement.OPENING_POSITION = OPENING_POSITION;
      rootElement.setSelectElement = this.setSelectElement.bind(this);
      rootElement.setOpen = this.setOpen.bind(this);
      rootElement.setOpeningPosition = this.setOpeningPosition.bind(this);
      this._onChange = onChange.bind(null, this);
      SznElements.injectStyles(CSS_STYLES, 'szn-select--button');
    }

    onMount() {
      observeSelect(this);
      addEventListeners(this);
      updateLabel(this);
      updateDisabledStatus(this);
    }

    onUnmount() {
      this._observer.disconnect();

      removeEventListeners(this);
    }

    setSelectElement(selectElement) {
      if (selectElement === this._select) {
        return;
      }

      if (!this._label) {
        this._root.appendChild(buildUI(this));
      }

      if (this._select) {
        removeEventListeners(this);

        this._observer.disconnect();
      }

      this._select = selectElement;
      observeSelect(this);
      addEventListeners(this);
      updateLabel(this);
      updateDisabledStatus(this);
    }

    setOpen(isOpen) {
      if (isOpen) {
        this._root.setAttribute('data-szn-select--button--open', '');
      } else {
        this._root.removeAttribute('data-szn-select--button--open');

        this._root.removeAttribute('data-szn-select--button--open-at-top');
      }
    }

    setOpeningPosition(openingPosition) {
      if (openingPosition === OPENING_POSITION.UP) {
        this._root.setAttribute('data-szn-select--button--open-at-top', '');
      } else {
        this._root.removeAttribute('data-szn-select--button--open-at-top');
      }
    }

  };

  function addEventListeners(instance) {
    if (!instance._select) {
      return;
    }

    instance._select.addEventListener('change', instance._onChange);
  }

  function removeEventListeners(instance) {
    if (!instance._select) {
      return;
    }

    instance._select.removeEventListener('change', instance._onChange);
  }

  function onChange(instance) {
    updateLabel(instance);
  }

  function observeSelect(instance) {
    if (!instance._select) {
      return;
    }

    instance._observer.observe(instance._select, {
      childList: true,
      attributes: true,
      characterData: true,
      subtree: true,
      attributeFilter: ['disabled', 'selected']
    });
  }

  function buildUI(instance) {
    return SznElements.buildDom(`
        <szn- data-szn-select--button--label data-szn-ref></szn->
        <szn- data-szn-select--button--mark></szn->
      `, label => {
      instance._label = label;
    }, false);
  }

  function updateLabel(instance) {
    if (!instance._select) {
      return;
    }

    const selectedOption = instance._select.options.item(instance._select.selectedIndex);

    const selectedOptionText = selectedOption.text;

    if (instance._label.innerText !== selectedOptionText) {
      instance._label.innerText = selectedOptionText;
    }
  }

  function updateDisabledStatus(instance) {
    if (!instance._select) {
      return;
    }

    if (instance._select.disabled) {
      instance._root.setAttribute('disabled', '');
    } else {
      instance._root.removeAttribute('disabled');
    }
  }
})(self);

'use strict';

(global => {
  const SznElements = global.SznElements = global.SznElements || {};
  const CSS_STYLES = `
szn-select--options{display:block;z-index:1;border:solid #ccc;border:solid var(--szn-select--options--border-color,#ccc);border-width:1px;border-width:var(--szn-select--options--border-width,1px);border-radius:0 0 4px 4px;border-radius:var(--szn-select--options--border-radius-dropdown,0 0 4px 4px);height:100%;box-sizing:border-box;white-space:nowrap;color:#000;color:var(--szn-select--options--text-color,#000);background:#fff;background:var(--szn-select--options--background-color,#fff);user-select:none;-moz-user-select:none}szn-select--options[data-szn-select--options--multiple]{border-radius:4px;border-radius:var(--szn-select--options--border-radius-mutli-select,4px)}szn-select--options [data-szn-select--options--option]{display:block;padding:5px 5px 5px 12px;padding:var(--szn-select--options--item-padding,5px 5px 5px 12px);overflow:auto;overflow-x:hidden;text-overflow:ellipsis;cursor:pointer}szn-select--options [data-szn-select--options--option][disabled],szn-select--options [disabled] [data-szn-select--options--option],szn-select--options[disabled] [data-szn-select-options--option]{cursor:default}szn-select--options [data-szn-select--options--selected]{background:#eee;background:var(--szn-select--options--selected-background,#eee)}szn-select--options [data-szn-select--options--optgroup]{display:block}szn-select--options [data-szn-select--options--optgroup] [data-szn-select--options--option]{padding-left:24px;padding-left:calc(2 * var(--szn-select--options--item-indent, 12px))}szn-select--options [data-szn-select--options--optgroup-label]:before{display:block;padding:5px 5px 5px 12px;padding:var(--szn-select--options--item-padding,5px 5px 5px 12px);content:attr(data-szn-select--options--optgroup-label);font-weight:700}szn-select--options[data-szn-select--options--highlighting] [data-szn-select-options--selected]{background:none}szn-select--options[data-szn-select--options--highlighting] [data-szn-select--options--highlighted]{background:#eee;background:var(--szn-select--options--selected-background,#eee)}szn-select--options[disabled],szn-select--options [disabled]{color:#ccc;color:var(--szn-select--options--disabled-text,#ccc)}szn-tethered[data-vertical-align=top] szn-select--options{border-radius:4px 4px 0 0;border-radius:var(--szn-select--options--border-radius-dropup,4px 4px 0 0)}
  `;

  class SznSelectOptions {
    /**
     * Initializes the szn-options element's implementation.
     *
     * @param {Element} rootElement The root HTML element of this custom element's implementation.
     */
    constructor(rootElement) {
      rootElement.setOptions = options => this.setOptions(options);

      rootElement.updateUi = () => updateUi(this);
      /**
       * The root HTML element of this custom element's implementation.
       *
       * @type {Element}
       */


      this._root = rootElement;
      /**
       * The container of the options this element provides the UI for.
       *
       * @type {?HTMLElement}
       */

      this._options = null;
      /**
       * The option represented the element over which the user started to drag the mouse cursor to perform a
       * multiple-items selection.
       *
       * This field is used only for multi-selects.
       *
       * @type {?HTMLOptionElement}
       */

      this._dragSelectionStartOption = null;
      /**
       * Flag signalling whether the element is currently mounted.
       *
       * @type {boolean}
       */

      this._mounted = false;
      /**
       * The DOM mutation observer used to observe modifications to the associated options.
       *
       * @type {MutationObserver}
       */

      this._observer = new MutationObserver(rootElement.updateUi);
      /**
       * The previously used indexes when the <code>scrollToSelection</code> function has been called for this
       * instance.
       *
       * @type {{start: number, end: number}}
       * @see scrollToSelection
       */

      this._lastSelectionIndexes = {
        start: -1,
        end: -1
        /**
         * The indexes of options that are to be selected as well while performing an additive multi-select (dragging the
         * mouse over a multi-select while holding the Ctrl key).
         *
         * @type {Array<number>}
         */

      };
      this._additionalSelectedIndexes = [];
      /**
       * Set to <code>true</code> if the user started to drag the mouse pointer over an already selected item while
       * holding the Ctrl key. The items selected by the user using the current action will be deselected.
       *
       * @type {boolean}
       */

      this._invertSelection = false;
      /**
       * The index of the option at which the multi-items selection started the last time.
       *
       * @type {number}
       */

      this._previousSelectionStartIndex = -1;
      /**
       * The ID of the current touch being observed for possible option interaction.
       *
       * @type {?number}
       */

      this._observedTouchId = null;

      this._onItemHovered = event => onItemHovered(this, event.target);

      this._onItemClicked = event => onItemClicked(this, event.target);

      this._onItemSelectionStart = event => onItemSelectionStart(this, event.target, event);

      this._onTouchStart = onTouchStart.bind(null, this);
      this._onTouchEnd = onTouchEnd.bind(null, this);

      this._onSelectionEnd = () => {
        this._dragSelectionStartOption = null;
        this._additionalSelectedIndexes = [];
      };

      this._onSelectionChange = () => {
        this._root.removeAttribute('data-szn-select--options--highlighting');

        updateUi(this);
      };

      SznElements.injectStyles(CSS_STYLES, 'szn-options');
    }

    onMount() {
      this._mounted = true;
      addEventListeners(this);
      updateUi(this);
      registerOptionsObserver(this);

      if (this._options) {
        scrollToSelection(this, this._options.selectedIndex, this._options.selectedIndex);
      }
    }

    onUnmount() {
      removeEventListeners(this);

      this._root.removeAttribute('data-szn-select--options--highlighting');

      this._mounted = false;

      this._observer.disconnect();
    }
    /**
     * Sets the element containing the options to display in this szn-options element.
     *
     * @param {HTMLElement} options The element containing the options to display.
     */


    setOptions(options) {
      if (options === this._options) {
        return;
      }

      if (this._options) {
        removeEventListeners(this);

        this._observer.disconnect();
      }

      this._options = options;
      addEventListeners(this);
      updateUi(this);
      registerOptionsObserver(this);
      const selectedIndex = typeof options.selectedIndex === 'number' ? options.selectedIndex : -1;
      this._previousSelectionStartIndex = selectedIndex;

      if (this._mounted) {
        scrollToSelection(this, selectedIndex, selectedIndex);
      }
    }

  }
  /**
   * Registers the provided szn-options element's DOM mutation observer to observe the related options for changes.
   *
   * @param {SznSelectOptions} instance The szn-options element instance.
   */


  function registerOptionsObserver(instance) {
    if (!instance._mounted || !instance._options) {
      return;
    }

    instance._observer.observe(instance._options, {
      childList: true,
      attributes: true,
      characterData: true,
      subtree: true,
      attributeFilter: ['disabled', 'label', 'selected', 'title', 'multiple']
    });
  }
  /**
   * Registers event listeners that the provided szn-options instance requires to function correctly.
   *
   * The function has no effect if the provided szn-options element is not mounted into the document or has not been
   * provided with its options yet.
   *
   * @param {SznSelectOptions} instance The szn-options element instance.
   */


  function addEventListeners(instance) {
    if (!instance._mounted || !instance._options) {
      return;
    }

    instance._options.addEventListener('change', instance._onSelectionChange);

    instance._root.addEventListener('mouseover', instance._onItemHovered);

    instance._root.addEventListener('mousedown', instance._onItemSelectionStart);

    instance._root.addEventListener('mouseup', instance._onItemClicked);

    instance._root.addEventListener('touchstart', instance._onTouchStart);

    addEventListener('mouseup', instance._onSelectionEnd);
    addEventListener('touchend', instance._onTouchEnd);
  }
  /**
   * Deregisters all event listeners used by the provided szn-options element.
   *
   * @param {SznSelectOptions} instance The szn-options element instance.
   */


  function removeEventListeners(instance) {
    if (instance._options) {
      instance._options.removeEventListener('change', instance._onSelectionChange);
    }

    instance._root.removeEventListener('mouseover', instance._onItemHovered);

    instance._root.removeEventListener('mousedown', instance._onItemSelectionStart);

    instance._root.removeEventListener('mouseup', instance._onItemClicked);

    instance._root.removeEventListener('touchstart', instance._onTouchStart);

    removeEventListener('mouseup', instance._onSelectionEnd);
    removeEventListener('touchend', instance._onTouchEnd);
  }
  /**
   * @param {SznSelectOptions} instance
   * @param {TouchEvent} event
   */


  function onTouchStart(instance, event) {
    if (instance._observedTouchId) {
      return;
    }

    const touch = event.changedTouches[0];
    instance._observedTouchId = touch.identifier;
  }

  function onTouchEnd(instance, event) {
    if (!instance._options.multiple) {
      return;
    }

    const touch = Array.from(event.changedTouches).find(someTouch => someTouch.identifier === instance._observedTouchId);

    if (!touch) {
      return;
    }

    instance._observedTouchId = null;
    event.preventDefault(); // prevent mouse events

    const option = event.target._option;

    if (!isOptionEnabled(option)) {
      return;
    }

    option.selected = !option.selected;

    instance._options.dispatchEvent(new CustomEvent('change', {
      bubbles: true,
      cancelable: true
    }));
  }
  /**
   * Handles the user moving the mouse pointer over an option in the szn-options element's UI. The function updates the
   * current multiple-items selection if the element represents a multi-select, or updates the currently highlighted
   * item in the UI of a single-select.
   *
   * @param {SznSelectOptions} instance The szn-options element instance.
   * @param {Element} itemUi The element which's area the mouse pointer entered.
   */


  function onItemHovered(instance, itemUi) {
    if (instance._options.disabled || !isEnabledOptionUi(itemUi)) {
      return;
    }

    if (instance._options.multiple) {
      if (instance._dragSelectionStartOption) {
        updateMultiSelection(instance, itemUi);
      }

      return;
    }

    instance._root.setAttribute('data-szn-select--options--highlighting', '');

    const previouslyHighlighted = instance._root.querySelector('[data-szn-select--options--highlighted]');

    if (previouslyHighlighted) {
      previouslyHighlighted.removeAttribute('data-szn-select--options--highlighted');
    }

    itemUi.setAttribute('data-szn-select--options--highlighted', '');
  }
  /**
   * Handles the user releasing the primary mouse button over an element representing an item.
   *
   * The function ends multiple-items selection for multi-selects, ends options highlighting and marks the the selected
   * option for single-selects.
   *
   * @param {SznSelectOptions} instance The szn-options element instance.
   * @param {Element} itemUi The element at which the user released the primary mouse button.
   */


  function onItemClicked(instance, itemUi) {
    if (instance._dragSelectionStartOption) {
      // multi-select
      instance._dragSelectionStartOption = null;
      return;
    }

    if (instance._options.disabled || !isEnabledOptionUi(itemUi)) {
      return;
    }

    instance._root.removeAttribute('data-szn-select--options--highlighting');

    instance._options.selectedIndex = itemUi._option.index;

    instance._options.dispatchEvent(new CustomEvent('change', {
      bubbles: true,
      cancelable: true
    }));
  }
  /**
   * Handles start of the user dragging the mouse pointer over the UI of a multi-selection szn-options element. The
   * function marks the starting item.
   *
   * The function marks the starting item used previously as the current starting item if the Shift key is pressed. The
   * function marks the indexes of the currently selected items if the Ctrl key is pressed and the Shift key is not.
   * Also, if the Ctrl key pressed, the Shift key is not, and the user starts at an already selected item, the function
   * will mark this as inverted selection.
   *
   * The function has no effect for single-selects.
   *
   * @param {SznSelectOptions} instance The szn-options element instance.
   * @param {Element} itemUi The element at which the user pressed the primary mouse button down.
   * @param {MouseEvent} event The mouse event representing the user's action.
   */


  function onItemSelectionStart(instance, itemUi, event) {
    if (instance._options.disabled || !instance._options.multiple || !isEnabledOptionUi(itemUi)) {
      return;
    }

    const options = instance._options.options;

    if (event.shiftKey && instance._previousSelectionStartIndex > -1) {
      instance._dragSelectionStartOption = options.item(instance._previousSelectionStartIndex);
    } else {
      if (event.ctrlKey) {
        instance._additionalSelectedIndexes = [];

        for (let i = 0, length = options.length; i < length; i++) {
          if (options.item(i).selected) {
            instance._additionalSelectedIndexes.push(i);
          }
        }

        instance._invertSelection = itemUi._option.selected;
      } else {
        instance._invertSelection = false;
      }

      instance._dragSelectionStartOption = itemUi._option;
    }

    instance._previousSelectionStartIndex = instance._dragSelectionStartOption.index;
    updateMultiSelection(instance, itemUi);
  }
  /**
   * Scrolls, only if necessary, the UI of the provided szn-options element to make the last selected option visible.
   * Which option is the last selected one is determined by comparing the provided index with the indexes passed to the
   * previous call of this function.
   *
   * @param {SznSelectOptions} instance The szn-options element instance.
   * @param {number} selectionStartIndex The index of the first selected option. The index must be a non-negative
   *        integer and cannot be greater that the total number of options; or set to <code>-1</code> if there is no
   *        option currently selected.
   * @param {number} selectionEndIndex The index of the last selected option. The index must be a non-negative integer,
   *        cannot be greater than the total number of options and must not be lower than the
   *        <code>selectionStartIndex</code>; or set to <code>-1</code> if there is no option currently selected.
   */


  function scrollToSelection(instance, selectionStartIndex, selectionEndIndex) {
    const lastSelectionIndexes = instance._lastSelectionIndexes;

    if (selectionStartIndex !== -1 && (selectionStartIndex !== lastSelectionIndexes.start || selectionEndIndex !== lastSelectionIndexes.end)) {
      const changedIndex = selectionStartIndex !== lastSelectionIndexes.start ? selectionStartIndex : selectionEndIndex;
      scrollToOption(instance, changedIndex);
    }

    lastSelectionIndexes.start = selectionStartIndex;
    lastSelectionIndexes.end = selectionEndIndex;
  }
  /**
   * Scrolls, only if necessary, the UI of the provided szn-options element to make the option at the specified index
   * fully visible.
   *
   * @param {SznSelectOptions} instance The szn-options element instance.
   * @param {number} optionIndex The index of the option to select. The index must be a non-negative integer and cannot
   *        be greater than the total number of options.
   */


  function scrollToOption(instance, optionIndex) {
    const ui = instance._root;

    if (ui.clientHeight >= ui.scrollHeight) {
      return;
    }

    const uiBounds = ui.getBoundingClientRect();

    const options = instance._root.querySelectorAll('[data-szn-select--options--option]');

    const optionBounds = options[optionIndex].getBoundingClientRect();

    if (optionBounds.top >= uiBounds.top && optionBounds.bottom <= uiBounds.bottom) {
      return;
    }

    const delta = optionBounds.top < uiBounds.top ? optionBounds.top - uiBounds.top : optionBounds.bottom - uiBounds.bottom;
    ui.scrollTop += delta;
  }
  /**
   * Updates the multiple-items selection. This function is meant to be used with multi-selects when the user is
   * selecting multiple items by dragging the mouse pointer over them.
   *
   * Any item which's index is in the provided instance's list of additionally selected items will be marked as
   * selected as well.
   *
   * @param {SznSelectOptions} instance The szn-options element instance.
   * @param {Element} lastHoveredItem The element representing the UI of the last option the user has hovered using
   *        their mouse pointer.
   */


  function updateMultiSelection(instance, lastHoveredItem) {
    const startIndex = instance._dragSelectionStartOption.index;
    const lastIndex = lastHoveredItem._option.index;
    const minIndex = Math.min(startIndex, lastIndex);
    const maxIndex = Math.max(startIndex, lastIndex);
    const options = instance._options.options;
    const additionalIndexes = instance._additionalSelectedIndexes;

    for (let i = 0, length = options.length; i < length; i++) {
      const option = options.item(i);

      if (isOptionEnabled(option)) {
        let isOptionSelected = additionalIndexes.indexOf(i) > -1;

        if (i >= minIndex && i <= maxIndex) {
          isOptionSelected = !instance._invertSelection;
        }

        option.selected = isOptionSelected;
      }
    }

    instance._options.dispatchEvent(new CustomEvent('change', {
      bubbles: true,
      cancelable: true
    }));
  }
  /**
   * Tests whether the provided elements represents the UI of an enabled option.
   *
   * @param {Element} optionUi The UI element to test.
   * @return {boolean} <code>true</code> iff the option is enabled and can be interacted with.
   * @see isOptionEnabled
   */


  function isEnabledOptionUi(optionUi) {
    return optionUi.hasAttribute('data-szn-select--options--option') && isOptionEnabled(optionUi._option);
  }
  /**
   * Tests whether the provided option is enabled - it is not disabled nor it is a child of a disabled options group.
   * The provided option cannot be an orphan.
   *
   * @param {HTMLOptionElement} option The option element to test.
   * @return {boolean} <code>true</code> iff the option is enabled and can be interacted with.
   */


  function isOptionEnabled(option) {
    return !option.disabled && !option.parentNode.disabled;
  }
  /**
   * Updates the UI, if the provided szn-options element has already been provided with the options to display. The
   * functions synchronizes the displayed UI to reflect the available options, their status, and scrolls to the last
   * selected option if it is not visible.
   *
   * @param {SznSelectOptions} instance The szn-options element's instance.
   */


  function updateUi(instance) {
    if (!instance._options) {
      return;
    }

    if (instance._options.disabled) {
      instance._root.setAttribute('disabled', '');
    } else {
      instance._root.removeAttribute('disabled');
    }

    if (instance._options.multiple) {
      instance._root.setAttribute('data-szn-select--options--multiple', '');
    } else {
      instance._root.removeAttribute('data-szn-select--options--multiple');
    }

    updateGroupUi(instance._root, instance._options);

    if (instance._mounted) {
      const options = instance._options.options;
      let lastSelectedIndex = -1;

      for (let i = options.length - 1; i >= 0; i--) {
        if (options.item(i).selected) {
          lastSelectedIndex = i;
          break;
        }
      }

      scrollToSelection(instance, instance._options.selectedIndex, lastSelectedIndex);
    }
  }
  /**
   * Updates the contents of the provided UI to reflect the options in the provided options container. The function
   * removes removed options from the UI, updates the existing and adds the missing ones.
   *
   * @param {Element} uiContainer The element containing the constructed UI reflecting the provided options.
   * @param {HTMLElement} optionsGroup The element containing the options to be reflected in the UI.
   */


  function updateGroupUi(uiContainer, optionsGroup) {
    removeRemovedItems(uiContainer, optionsGroup);
    updateExistingItems(uiContainer);
    addMissingItems(uiContainer, optionsGroup);
  }
  /**
   * Removes UI items from the UI that have been representing the options and option groups that have been removed from
   * the provided container of options.
   *
   * @param {Element} uiContainer The element containing the elements reflecting the provided options and providing the
   *        UI for the options.
   * @param {HTMLElement} optionsGroup The element containing the options for which this szn-options element is
   *        providing the UI.
   */


  function removeRemovedItems(uiContainer, optionsGroup) {
    const options = Array.prototype.slice.call(optionsGroup.children);
    let currentItemUi = uiContainer.firstElementChild;

    while (currentItemUi) {
      if (options.indexOf(currentItemUi._option) > -1) {
        currentItemUi = currentItemUi.nextElementSibling;
        continue;
      }

      const itemToRemove = currentItemUi;
      currentItemUi = currentItemUi.nextElementSibling;
      uiContainer.removeChild(itemToRemove);
    }
  }
  /**
   * Updates all items in the provided UI container to reflect the current state of their associated options.
   *
   * @param {Element} groupUi The element containing the elements representing the UIs of the options.
   */


  function updateExistingItems(groupUi) {
    let itemUi = groupUi.firstElementChild;

    while (itemUi) {
      updateItem(itemUi);
      itemUi = itemUi.nextElementSibling;
    }
  }
  /**
   * Updates the UI item to reflect the current state of its associated <code>option</code>/<code>optgroup</code>
   * element.
   *
   * If the element represents an option group (<code>optgroup</code>), the children options will be updated as well.
   *
   * @param {HTMLElement} itemUi The element representing the UI of an <code>option</code>/<code>optgroup</code>
   *        element.
   */


  function updateItem(itemUi) {
    const option = itemUi._option;

    if (option.disabled) {
      itemUi.setAttribute('disabled', '');
    } else {
      itemUi.removeAttribute('disabled');
    }

    if (option.tagName === 'OPTGROUP') {
      updateGroupUi(itemUi, option);
      itemUi.setAttribute('data-szn-select--options--optgroup-label', option.label);
      return;
    }

    itemUi.innerText = option.text;

    if (option.title) {
      itemUi.setAttribute('title', option.title);
    } else {
      itemUi.removeAttribute('title');
    }

    if (option.selected) {
      itemUi.setAttribute('data-szn-select--options--selected', '');
    } else {
      itemUi.removeAttribute('data-szn-select--options--selected');
    }
  }
  /**
   * Adds the options present in the options container missing the UI into the UI, while preserving the order of the
   * options. Option groups are added recursively.
   *
   * @param {Element} groupUi The element containing the UIs of the options. The new options will be inserted into this
   *        element's children.
   * @param {HTMLElement} options An element containing the <code>option</code> and <code>optgroup</code> elements that
   *        the UI reflects.
   */


  function addMissingItems(groupUi, options) {
    let nextItemUi = groupUi.firstElementChild;
    let nextOption = options.firstElementChild;

    while (nextOption) {
      if (!nextItemUi || nextItemUi._option !== nextOption) {
        const newItemUi = document.createElement('szn-');
        newItemUi._option = nextOption;
        newItemUi.setAttribute('data-szn-select--options--' + (nextOption.tagName === 'OPTGROUP' ? 'optgroup' : 'option'), '');
        updateItem(newItemUi);
        groupUi.insertBefore(newItemUi, nextItemUi);
      } else {
        nextItemUi = nextItemUi && nextItemUi.nextElementSibling;
      }

      nextOption = nextOption.nextElementSibling;
    }
  }

  SznElements['szn-select--options'] = SznSelectOptions;
})(self);

'use strict';

(global => {
  const SznElements = global.SznElements = global.SznElements || {};
  const CSS_STYLES = `
szn-select--ui{display:inline-block;width:100%;height:100%}szn-select--ui[data-szn-select--ui--active] szn-select--button,szn-select--ui[data-szn-select--ui--active] szn-select--options{border-color:#7dbfff;border-color:var(--szn-select--ui--active-border-color,#7dbfff);box-shadow:0 0 3px rgba(0,132,255,.4);box-shadow:var(--szn-select--ui--active-box-shadow,0 0 3px rgba(0,132,255,.4))}body>szn-tethered>[data-szn-select--ui--dropdown]{display:block;top:-1px;top:var(--szn-select--ui--dropdown-offset,-1px);min-width:109px;min-width:var(--szn-select--ui--dropdown-min-width,109px)}body>szn-tethered[data-vertical-align=top]>[data-szn-select--ui--dropdown]{bottom:-1px;bottom:var(--szn-select--ui--dropdown-offset,-1px)}
  `;
  const MIN_BOTTOM_SPACE = 160; // px

  const INTERACTION_DOM_EVENTS = ['mousedown', 'click', 'touchstart'];
  const RESIZE_RELATED_DOM_EVENTS = ['resize', 'scroll', 'wheel', 'touchmove'];
  const DEFAULT_DROPDOWN_CONTAINER = document.body;
  SznElements['szn-select--ui'] = class SznSelectUi {
    constructor(rootElement) {
      if (!rootElement.hasOwnProperty('minBottomSpace')) {
        Object.defineProperty(rootElement, 'minBottomSpace', {
          get: () => rootElement._broker._minBottomSpace,
          set: value => {
            if (rootElement._broker._dropdown && rootElement._broker._dropdown._broker) {
              rootElement._broker._dropdown.minBottomSpace = value;
            }

            rootElement._broker._minBottomSpace = value;
          }
        });
      }

      if (!rootElement.hasOwnProperty('dropdownClassName')) {
        Object.defineProperty(rootElement, 'dropdownClassName', {
          get: () => rootElement._broker._dropdownClassName,
          set: value => {
            const broker = rootElement._broker;
            broker._dropdownClassName = value;

            if (broker._dropdownOptions && broker._select && !broker._select.multiple) {
              broker._dropdownOptions.className = value;
            }
          }
        });
      }

      if (!rootElement.hasOwnProperty('dropdownContainer')) {
        Object.defineProperty(rootElement, 'dropdownContainer', {
          get: () => rootElement._broker._dropdownContainer,
          set: value => {
            if (typeof Node === 'function'
            /* IE8 */
            && !(value instanceof Node)) {
              throw new TypeError('The provided dropdown container is not a DOM node: ' + value);
            }

            const instance = rootElement._broker;

            if (!instance || value === instance._dropdownContainer) {
              return;
            }

            const isDropdownRebuildNeeded = [instance._dropdownContainer, value].includes(DEFAULT_DROPDOWN_CONTAINER);
            instance._dropdownContainer = value;

            if (!instance._dropdown || !instance._dropdown.parentNode) {
              return;
            }

            if (isDropdownRebuildNeeded) {
              instance._dropdown = createDropdown(instance);
              value.appendChild(instance._dropdown);

              if (value === DEFAULT_DROPDOWN_CONTAINER) {
                onDropdownPositionChange(instance, instance._dropdown.verticalAlignment);
              } else {
                instance._dropdownContent.style.height = '';
              }
            } else {
              value.appendChild(instance._dropdown);
            }
          }
        });
      }

      rootElement.setSelectElement = this.setSelectElement.bind(this);
      rootElement.setFocus = this.setFocus.bind(this);
      rootElement.setOpen = this.setOpen.bind(this);
      rootElement.onUiInteracted = rootElement.onUiInteracted || null;
      this._root = rootElement;
      this._select = null;
      this._button = null;
      this._dropdown = null;
      this._dropdownClassName = '';
      this._dropdownPosition = null;
      this._dropdownContent = SznElements.buildDom('<szn- data-szn-select--ui--dropdown data-szn-tethered--content></szn->');
      this._dropdownOptions = null;
      this._dropdownContainer = DEFAULT_DROPDOWN_CONTAINER;
      this._minBottomSpace = MIN_BOTTOM_SPACE;
      this._observer = new MutationObserver(onDomMutated.bind(this));
      this._onDropdownPositionChange = onDropdownPositionChange.bind(null, this);
      this._onDropdownSizeUpdateNeeded = onDropdownSizeUpdateNeeded.bind(null, this);
      this._onUiInteracted = onUiInteracted.bind(null, this);
      SznElements.injectStyles(CSS_STYLES, 'szn-select--ui');
    }

    onMount() {
      this._root.setAttribute('aria-hidden', 'true');

      addEventListeners(this);

      this._observer.observe(this._root, {
        childList: true,
        attributes: true,
        characterData: true,
        subtree: true,
        attributeFilter: ['disabled', 'multiple', 'selected']
      });
    }

    onUnmount() {
      if (this._dropdown && this._dropdown.parentNode) {
        this._dropdown.parentNode.removeChild(this._dropdown);
      }

      removeEventListeners(this);

      this._observer.disconnect();
    }

    setSelectElement(select) {
      if (select === this._select) {
        return;
      }

      this._select = select;
      createUI(this);
    }

    setOpen(isOpen) {
      if (this._select.multiple || this._select.disabled) {
        return;
      }

      if (isOpen) {
        if (this._button._broker) {
          this._button.setOpen(true);
        }

        this._dropdownContainer.appendChild(this._dropdown);

        let dropdownReady = false;
        let optionsReady = false;
        SznElements.awaitElementReady(this._dropdown, () => {
          dropdownReady = true;

          if (optionsReady) {
            initDropdown(this, this._dropdown, this._dropdownOptions);
          }
        });
        SznElements.awaitElementReady(this._dropdownOptions, () => {
          optionsReady = true;

          if (dropdownReady) {
            initDropdown(this, this._dropdown, this._dropdownOptions);
          }
        });
      } else {
        if (!this._dropdown.parentNode) {
          return;
        }

        if (this._button._broker) {
          this._button.setOpen(false);
        }

        this._dropdown.parentNode.removeChild(this._dropdown);
      }
    }

    setFocus(hasFocus) {
      if (hasFocus) {
        this._root.setAttribute('data-szn-select--ui--active', '');
      } else {
        this._root.removeAttribute('data-szn-select--ui--active');
      }
    }

  };

  function addEventListeners(instance) {
    for (const eventType of INTERACTION_DOM_EVENTS) {
      instance._root.addEventListener(eventType, instance._onUiInteracted);
    }

    for (const eventType of RESIZE_RELATED_DOM_EVENTS) {
      addEventListener(eventType, instance._onDropdownSizeUpdateNeeded);
    }
  }

  function removeEventListeners(instance) {
    for (const eventType of INTERACTION_DOM_EVENTS) {
      instance._root.removeEventListener(eventType, instance._onUiInteracted);

      instance._dropdownContent.removeEventListener(eventType, instance._onUiInteracted);

      instance._dropdownContainer.removeEventListener(eventType, instance._onUiInteracted);
    }

    for (const eventType of RESIZE_RELATED_DOM_EVENTS) {
      removeEventListener(eventType, instance._onDropdownSizeUpdateNeeded);
    }
  }

  function onUiInteracted(instance, event) {
    if (instance._root.onUiInteracted) {
      instance._root.onUiInteracted(event);
    }
  }

  function onDomMutated(instance) {
    // Since we are mutating our subtree, there will be false positives, so we always need to check what has changed
    const select = instance._select;

    if (select && (select.multiple && instance._button || !select.multiple && !instance._button)) {
      createUI(instance);
    }
  }

  function onDropdownSizeUpdateNeeded(instance) {
    if (!instance._dropdown || !instance._dropdown._broker || !instance._dropdownOptions._broker || instance._dropdownContainer !== DEFAULT_DROPDOWN_CONTAINER) {
      return;
    }

    const