dropdown.js

/**
 * --------------------------------------------------------------------------
 * Bootstrap (v4.3.1): dropdown.js
 * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
 * --------------------------------------------------------------------------
 */

import {
  jQuery as $,
  getSelectorFromElement,
  isElement,
  makeArray,
  noop,
  typeCheckConfig
} from '../util/index'
import Data from '../dom/data'
import EventHandler from '../dom/event-handler'
import Manipulator from '../dom/manipulator'
import Popper from 'popper.js'
import SelectorEngine from '../dom/selector-engine'

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

const NAME = 'dropdown'
const VERSION = '4.3.1'
const DATA_KEY = 'bs.dropdown'
const EVENT_KEY = `.${DATA_KEY}`
const DATA_API_KEY = '.data-api'
const ESCAPE_KEYCODE = 27 // KeyboardEvent.which value for Escape (Esc) key
const SPACE_KEYCODE = 32 // KeyboardEvent.which value for space key
const TAB_KEYCODE = 9 // KeyboardEvent.which value for tab key
const ARROW_UP_KEYCODE = 38 // KeyboardEvent.which value for up arrow key
const ARROW_DOWN_KEYCODE = 40 // KeyboardEvent.which value for down arrow key
const RIGHT_MOUSE_BUTTON_WHICH = 3 // MouseEvent.which value for the right button (assuming a right-handed mouse)
const REGEXP_KEYDOWN = new RegExp(`${ARROW_UP_KEYCODE}|${ARROW_DOWN_KEYCODE}|${ESCAPE_KEYCODE}`)

const Event = {
  HIDE: `hide${EVENT_KEY}`,
  HIDDEN: `hidden${EVENT_KEY}`,
  SHOW: `show${EVENT_KEY}`,
  SHOWN: `shown${EVENT_KEY}`,
  CLICK: `click${EVENT_KEY}`,
  CLICK_DATA_API: `click${EVENT_KEY}${DATA_API_KEY}`,
  KEYDOWN_DATA_API: `keydown${EVENT_KEY}${DATA_API_KEY}`,
  KEYUP_DATA_API: `keyup${EVENT_KEY}${DATA_API_KEY}`
}

const ClassName = {
  DISABLED: 'disabled',
  SHOW: 'show',
  DROPUP: 'dropup',
  DROPRIGHT: 'dropright',
  DROPLEFT: 'dropleft',
  MENURIGHT: 'dropdown-menu-right',
  POSITION_STATIC: 'position-static'
}

const Selector = {
  DATA_TOGGLE: '[data-toggle="dropdown"]',
  FORM_CHILD: '.dropdown form',
  MENU: '.dropdown-menu',
  NAVBAR_NAV: '.navbar-nav',
  VISIBLE_ITEMS: '.dropdown-menu .dropdown-item:not(.disabled):not(:disabled)'
}

const AttachmentMap = {
  TOP: 'top-start',
  TOPEND: 'top-end',
  BOTTOM: 'bottom-start',
  BOTTOMEND: 'bottom-end',
  RIGHT: 'right-start',
  RIGHTEND: 'right-end',
  LEFT: 'left-start',
  LEFTEND: 'left-end'
}

const Default = {
  offset: 0,
  flip: true,
  boundary: 'scrollParent',
  reference: 'toggle',
  display: 'dynamic'
}

const DefaultType = {
  offset: '(number|string|function)',
  flip: 'boolean',
  boundary: '(string|element)',
  reference: '(string|element)',
  display: 'string'
}

/**
 * ------------------------------------------------------------------------
 * Class Definition
 * ------------------------------------------------------------------------
 */

class Dropdown {
  constructor(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, this)
  }

  // Getters

  static get VERSION() {
    return VERSION
  }

  static get Default() {
    return Default
  }

  static get DefaultType() {
    return DefaultType
  }

  // Public

  toggle() {
    if (this._element.disabled || this._element.classList.contains(ClassName.DISABLED)) {
      return
    }

    const parent = Dropdown._getParentFromElement(this._element)
    const isActive = this._menu.classList.contains(ClassName.SHOW)

    Dropdown._clearMenus()

    if (isActive) {
      return
    }

    const relatedTarget = {
      relatedTarget: this._element
    }
    const showEvent = EventHandler.trigger(parent, Event.SHOW, relatedTarget)

    if (showEvent.defaultPrevented) {
      return
    }

    // Disable totally Popper.js for Dropdown in Navbar
    if (!this._inNavbar) {
      /**
       * Check for Popper dependency
       * Popper - https://popper.js.org
       */
      if (typeof Popper === 'undefined') {
        throw new TypeError('Bootstrap\'s dropdowns require Popper.js (https://popper.js.org)')
      }

      let 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(ClassName.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 &&
      !makeArray(SelectorEngine.closest(parent, Selector.NAVBAR_NAV)).length) {
      makeArray(document.body.children)
        .forEach(elem => EventHandler.on(elem, 'mouseover', null, noop()))
    }

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

    Manipulator.toggleClass(this._menu, ClassName.SHOW)
    Manipulator.toggleClass(parent, ClassName.SHOW)
    EventHandler.trigger(parent, Event.SHOWN, relatedTarget)
  }

  show() {
    if (this._element.disabled || this._element.classList.contains(ClassName.DISABLED) || this._menu.classList.contains(ClassName.SHOW)) {
      return
    }

    const parent = Dropdown._getParentFromElement(this._element)
    const relatedTarget = {
      relatedTarget: this._element
    }

    const showEvent = EventHandler.trigger(parent, Event.SHOW, relatedTarget)

    if (showEvent.defaultPrevented) {
      return
    }

    Manipulator.toggleClass(this._menu, ClassName.SHOW)
    Manipulator.toggleClass(parent, ClassName.SHOW)
    EventHandler.trigger(parent, Event.SHOWN, relatedTarget)
  }

  hide() {
    if (this._element.disabled || this._element.classList.contains(ClassName.DISABLED) || !this._menu.classList.contains(ClassName.SHOW)) {
      return
    }

    const parent = Dropdown._getParentFromElement(this._element)
    const relatedTarget = {
      relatedTarget: this._element
    }

    const hideEvent = EventHandler.trigger(parent, Event.HIDE, relatedTarget)

    if (hideEvent.defaultPrevented) {
      return
    }

    Manipulator.toggleClass(this._menu, ClassName.SHOW)
    Manipulator.toggleClass(parent, ClassName.SHOW)
    EventHandler.trigger(parent, Event.HIDDEN, relatedTarget)
  }

  dispose() {
    Data.removeData(this._element, DATA_KEY)
    EventHandler.off(this._element, EVENT_KEY)
    this._element = null
    this._menu = null
    if (this._popper !== null) {
      this._popper.destroy()
      this._popper = null
    }
  }

  update() {
    this._inNavbar = this._detectNavbar()
    if (this._popper !== null) {
      this._popper.scheduleUpdate()
    }
  }

  // Private

  _addEventListeners() {
    EventHandler.on(this._element, Event.CLICK, event => {
      event.preventDefault()
      event.stopPropagation()
      this.toggle()
    })
  }

  _getConfig(config) {
    config = {
      ...this.constructor.Default,
      ...Manipulator.getDataAttributes(this._element),
      ...config
    }

    typeCheckConfig(
      NAME,
      config,
      this.constructor.DefaultType
    )

    return config
  }

  _getMenuElement() {
    const parent = Dropdown._getParentFromElement(this._element)

    return SelectorEngine.findOne(Selector.MENU, parent)
  }

  _getPlacement() {
    const parentDropdown = this._element.parentNode
    let placement = AttachmentMap.BOTTOM

    // Handle dropup
    if (parentDropdown.classList.contains(ClassName.DROPUP)) {
      placement = AttachmentMap.TOP
      if (this._menu.classList.contains(ClassName.MENURIGHT)) {
        placement = AttachmentMap.TOPEND
      }
    } else if (parentDropdown.classList.contains(ClassName.DROPRIGHT)) {
      placement = AttachmentMap.RIGHT
    } else if (parentDropdown.classList.contains(ClassName.DROPLEFT)) {
      placement = AttachmentMap.LEFT
    } else if (this._menu.classList.contains(ClassName.MENURIGHT)) {
      placement = AttachmentMap.BOTTOMEND
    }

    return placement
  }

  _detectNavbar() {
    return Boolean(SelectorEngine.closest(this._element, '.navbar'))
  }

  _getOffset() {
    const offset = {}

    if (typeof this._config.offset === 'function') {
      offset.fn = data => {
        data.offsets = {
          ...data.offsets,
          ...this._config.offset(data.offsets, this._element) || {}
        }

        return data
      }
    } else {
      offset.offset = this._config.offset
    }

    return offset
  }

  _getPopperConfig() {
    const 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 popperConfig
  }

  // Static

  static _dropdownInterface(element, config) {
    let data = Data.getData(element, DATA_KEY)
    const _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]()
    }
  }

  static _jQueryInterface(config) {
    return this.each(function () {
      Dropdown._dropdownInterface(this, config)
    })
  }

  static _clearMenus(event) {
    if (event && (event.which === RIGHT_MOUSE_BUTTON_WHICH ||
      event.type === 'keyup' && event.which !== TAB_KEYCODE)) {
      return
    }

    const toggles = makeArray(SelectorEngine.find(Selector.DATA_TOGGLE))
    for (let i = 0, len = toggles.length; i < len; i++) {
      const parent = Dropdown._getParentFromElement(toggles[i])
      const context = Data.getData(toggles[i], DATA_KEY)
      const relatedTarget = {
        relatedTarget: toggles[i]
      }

      if (event && event.type === 'click') {
        relatedTarget.clickEvent = event
      }

      if (!context) {
        continue
      }

      const dropdownMenu = context._menu
      if (!parent.classList.contains(ClassName.SHOW)) {
        continue
      }

      if (event && (event.type === 'click' &&
          /input|textarea/i.test(event.target.tagName) ||
          event.type === 'keyup' && event.which === TAB_KEYCODE) &&
          parent.contains(event.target)) {
        continue
      }

      const hideEvent = EventHandler.trigger(parent, Event.HIDE, relatedTarget)
      if (hideEvent.defaultPrevented) {
        continue
      }

      // If this is a touch-enabled device we remove the extra
      // empty mouseover listeners we added for iOS support
      if ('ontouchstart' in document.documentElement) {
        makeArray(document.body.children)
          .forEach(elem => EventHandler.off(elem, 'mouseover', null, noop()))
      }

      toggles[i].setAttribute('aria-expanded', 'false')

      dropdownMenu.classList.remove(ClassName.SHOW)
      parent.classList.remove(ClassName.SHOW)
      EventHandler.trigger(parent, Event.HIDDEN, relatedTarget)
    }
  }

  static _getParentFromElement(element) {
    let parent
    const selector = getSelectorFromElement(element)

    if (selector) {
      parent = SelectorEngine.findOne(selector)
    }

    return parent || element.parentNode
  }

  static _dataApiKeydownHandler(event) {
    // If not input/textarea:
    //  - And not a key in REGEXP_KEYDOWN => not a dropdown command
    // If input/textarea:
    //  - If space key => not a dropdown command
    //  - If key is other than escape
    //    - If key is not up or down => not a dropdown command
    //    - If trigger inside the menu => not a dropdown command
    if (/input|textarea/i.test(event.target.tagName) ?
      event.which === SPACE_KEYCODE || event.which !== ESCAPE_KEYCODE &&
      (event.which !== ARROW_DOWN_KEYCODE && event.which !== ARROW_UP_KEYCODE ||
        SelectorEngine.closest(event.target, Selector.MENU)) :
      !REGEXP_KEYDOWN.test(event.which)) {
      return
    }

    event.preventDefault()
    event.stopPropagation()

    if (this.disabled || this.classList.contains(ClassName.DISABLED)) {
      return
    }

    const parent = Dropdown._getParentFromElement(this)
    const isActive = parent.classList.contains(ClassName.SHOW)

    if (!isActive || isActive && (event.which === ESCAPE_KEYCODE || event.which === SPACE_KEYCODE)) {
      if (event.which === ESCAPE_KEYCODE) {
        SelectorEngine.findOne(Selector.DATA_TOGGLE, parent).focus()
      }

      Dropdown._clearMenus()
      return
    }

    const items = makeArray(SelectorEngine.find(Selector.VISIBLE_ITEMS, parent))

    if (!items.length) {
      return
    }

    let index = items.indexOf(event.target)

    if (event.which === ARROW_UP_KEYCODE && index > 0) { // Up
      index--
    }

    if (event.which === ARROW_DOWN_KEYCODE && index < items.length - 1) { // Down
      index++
    }

    if (index < 0) {
      index = 0
    }

    items[index].focus()
  }

  static _getInstance(element) {
    return Data.getData(element, DATA_KEY)
  }
}

/**
 * ------------------------------------------------------------------------
 * Data Api implementation
 * ------------------------------------------------------------------------
 */

EventHandler.on(document, Event.KEYDOWN_DATA_API, Selector.DATA_TOGGLE, Dropdown._dataApiKeydownHandler)
EventHandler.on(document, Event.KEYDOWN_DATA_API, Selector.MENU, Dropdown._dataApiKeydownHandler)
EventHandler.on(document, Event.CLICK_DATA_API, Dropdown._clearMenus)
EventHandler.on(document, Event.KEYUP_DATA_API, Dropdown._clearMenus)
EventHandler.on(document, Event.CLICK_DATA_API, Selector.DATA_TOGGLE, function (event) {
  event.preventDefault()
  event.stopPropagation()
  Dropdown._dropdownInterface(this, 'toggle')
})
EventHandler
  .on(document, Event.CLICK_DATA_API, Selector.FORM_CHILD, e => e.stopPropagation())

/**
 * ------------------------------------------------------------------------
 * jQuery
 * ------------------------------------------------------------------------
 * add .dropdown to jQuery only if jQuery is present
 */
/* istanbul ignore if */
if (typeof $ !== 'undefined') {
  const JQUERY_NO_CONFLICT = $.fn[NAME]
  $.fn[NAME] = Dropdown._jQueryInterface
  $.fn[NAME].Constructor = Dropdown
  $.fn[NAME].noConflict = () => {
    $.fn[NAME] = JQUERY_NO_CONFLICT
    return Dropdown._jQueryInterface
  }
}

export default Dropdown