es6 alert :|

js/src/util.js

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+/**
+ * --------------------------------------------------------------------------
+ * 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()