Bootstrap/js/src/util.js

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


/**
 * --------------------------------------------------------------------------
 * Public Util Api
 * --------------------------------------------------------------------------
 */

var Util = {

  TRANSITION_END: 'bsTransitionEnd',

  getUID(prefix) {
    do prefix += ~~(Math.random() * 1000000)
    while (document.getElementById(prefix))
    return prefix
  },

  getSelectorFromElement(element) {
    let selector = element.getAttribute('data-target')

    if (!selector) {
      selector = element.getAttribute('href') || ''
      selector = /^#[a-z]/i.test(selector) ? selector : null
    }

    return selector
  },

  reflow(element) {
    new Function('bs', 'return bs')(element.offsetHeight)
  },

  supportsTransitionEnd() {
    return !!transition
  }

}

export default Util


/**
 * --------------------------------------------------------------------------
 * Private TransitionEnd Helpers
 * --------------------------------------------------------------------------
 */

let transition = false

const TransitionEndEvent = {
  WebkitTransition : 'webkitTransitionEnd',
  MozTransition    : 'transitionend',
  OTransition      : 'oTransitionEnd otransitionend',
  transition       : 'transitionend'
}

function getSpecialTransitionEndEvent() {
  return {
    bindType: transition.end,
    delegateType: transition.end,
    handle: function (event) {
      if ($(event.target).is(this)) {
        return event.handleObj.handler.apply(this, arguments)
      }
    }
  }
}

function transitionEndTest() {
  if (window.QUnit) {
    return false
  }

  let el = document.createElement('bootstrap')

  for (var name in TransitionEndEvent) {
    if (el.style[name] !== undefined) {
      return { end: TransitionEndEvent[name] }
    }
  }

  return false
}

function transitionEndEmulator(duration) {
  let called = false

  $(this).one(Util.TRANSITION_END, function () {
    called = true
  })

  setTimeout(() => {
    if (!called) {
      $(this).trigger(transition.end)
    }
  }, duration)

  return this
}

function setTransitionEndSupport() {
  transition = transitionEndTest()

  $.fn.emulateTransitionEnd = transitionEndEmulator

  if (Util.supportsTransitionEnd()) {
    $.event.special[Util.TRANSITION_END] = getSpecialTransitionEndEvent()
  }
}

setTransitionEndSupport()