js/src/dropdown.js @v4-dev

/* global Popper */

import Util from './util'


/**
 * --------------------------------------------------------------------------
 * Bootstrap (v4.0.0-alpha.6): dropdown.js
 * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
 * --------------------------------------------------------------------------
 */

const Dropdown = (($) => {

  /**
   * Check for Popper dependency
   * Popper - https://popper.js.org
   */
  if (typeof Popper === 'undefined') {
    throw new Error('Bootstrap dropdown require Popper.js (https://popper.js.org)')
  }

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

  const NAME                     = 'dropdown'
  const VERSION                  = '4.0.0-alpha.6'
  const DATA_KEY                 = 'bs.dropdown'
  const EVENT_KEY                = `.${DATA_KEY}`
  const DATA_API_KEY             = '.data-api'
  const JQUERY_NO_CONFLICT       = $.fn[NAME]
  const ESCAPE_KEYCODE           = 27 // KeyboardEvent.which value for Escape (Esc) key
  const SPACE_KEYCODE            = 32 // KeyboardEvent.which value for space key
  const TAB_KEYCODE              = 9 // KeyboardEvent.which value for tab key
  const ARROW_UP_KEYCODE         = 38 // KeyboardEvent.which value for up arrow key
  const ARROW_DOWN_KEYCODE       = 40 // KeyboardEvent.which value for down arrow key
  const RIGHT_MOUSE_BUTTON_WHICH = 3 // MouseEvent.which value for the right button (assuming a right-handed mouse)
  const REGEXP_KEYDOWN           = new RegExp(`${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}`,
...

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