Add back support for IE 11

js/src/dom/eventHandler.js

@@ -6,7 +6,7 @@
  */
 
 import { jQuery as $ } from '../util/index'
-import Polyfill from './polyfill'
+import { createCustomEvent, defaultPreventedPreservedOnDispatch } from './polyfill'
 
 /**
  * ------------------------------------------------------------------------
@@ -305,7 +305,7 @@ const EventHandler = {
       evt = document.createEvent('HTMLEvents')
       evt.initEvent(typeEvent, bubbles, true)
     } else {
-      evt = new CustomEvent(event, {
+      evt = createCustomEvent(event, {
         bubbles,
         cancelable: true
       })
@@ -326,7 +326,7 @@ const EventHandler = {
     if (defaultPrevented) {
       evt.preventDefault()
 
-      if (!Polyfill.defaultPreventedPreservedOnDispatch) {
+      if (!defaultPreventedPreservedOnDispatch) {
         Object.defineProperty(evt, 'defaultPrevented', {
           get: () => true
         })

js/src/dom/polyfill.js

@@ -1,3 +1,5 @@
+/* istanbul ignore file */
+
 /**
  * --------------------------------------------------------------------------
  * Bootstrap (v4.3.1): dom/polyfill.js
@@ -7,83 +9,144 @@
 
 import { getUID } from '../util/index'
 
-/* istanbul ignore next */
-const Polyfill = (() => {
-  // MSEdge resets defaultPrevented flag upon dispatchEvent call if at least one listener is attached
-  const defaultPreventedPreservedOnDispatch = (() => {
-    const e = new CustomEvent('Bootstrap', {
-      cancelable: true
-    })
+let { matches, closest } = Element.prototype
+let find = Element.prototype.querySelectorAll
+let findOne = Element.prototype.querySelector
+let createCustomEvent = (eventName, params) => {
+  const cEvent = new CustomEvent(eventName, params)
 
-    const element = document.createElement('div')
-    element.addEventListener('Bootstrap', () => null)
+  return cEvent
+}
 
-    e.preventDefault()
-    element.dispatchEvent(e)
-    return e.defaultPrevented
-  })()
+if (typeof window.CustomEvent !== 'function') {
+  createCustomEvent = (eventName, params) => {
+    params = params || { bubbles: false, cancelable: false, detail: null }
 
-  let find = Element.prototype.querySelectorAll
-  let findOne = Element.prototype.querySelector
+    const evt = document.createEvent('CustomEvent')
 
-  const scopeSelectorRegex = /:scope\b/
-  const supportScopeQuery = (() => {
-    const element = document.createElement('div')
-
-    try {
-      element.querySelectorAll(':scope *')
-    } catch (error) {
-      return false
-    }
-
-    return true
-  })()
-
-  if (!supportScopeQuery) {
-    find = function (selector) {
-      if (!scopeSelectorRegex.test(selector)) {
-        return this.querySelectorAll(selector)
-      }
-
-      const hasId = Boolean(this.id)
-
-      if (!hasId) {
-        this.id = getUID('scope')
-      }
-
-      let nodeList = null
-      try {
-        selector = selector.replace(scopeSelectorRegex, `#${this.id}`)
-        nodeList = this.querySelectorAll(selector)
-      } finally {
-        if (!hasId) {
-          this.removeAttribute('id')
-        }
-      }
-
-      return nodeList
-    }
-
-    findOne = function (selector) {
-      if (!scopeSelectorRegex.test(selector)) {
-        return this.querySelector(selector)
-      }
-
-      const matches = find.call(this, selector)
-
-      if (typeof matches[0] !== 'undefined') {
-        return matches[0]
-      }
-
-      return null
-    }
+    evt.initCustomEvent(eventName, params.bubbles, params.cancelable, params.detail)
+    return evt
   }
+}
 
-  return {
-    defaultPreventedPreservedOnDispatch,
-    find,
-    findOne
-  }
+const workingDefaultPrevented = (() => {
+  const e = document.createEvent('CustomEvent')
+
+  e.initEvent('Bootstrap', true, true)
+  e.preventDefault()
+  return e.defaultPrevented
 })()
 
-export default Polyfill
+if (!workingDefaultPrevented) {
+  const origPreventDefault = Event.prototype.preventDefault
+
+  Event.prototype.preventDefault = function () {
+    if (!this.cancelable) {
+      return
+    }
+
+    origPreventDefault.call(this)
+    Object.defineProperty(this, 'defaultPrevented', {
+      get() {
+        return true
+      },
+      configurable: true
+    })
+  }
+}
+
+// MSEdge resets defaultPrevented flag upon dispatchEvent call if at least one listener is attached
+const defaultPreventedPreservedOnDispatch = (() => {
+  const e = createCustomEvent('Bootstrap', {
+    cancelable: true
+  })
+
+  const element = document.createElement('div')
+  element.addEventListener('Bootstrap', () => null)
+
+  e.preventDefault()
+  element.dispatchEvent(e)
+  return e.defaultPrevented
+})()
+
+if (!matches) {
+  matches = Element.prototype.msMatchesSelector || Element.prototype.webkitMatchesSelector
+}
+
+if (!closest) {
+  closest = function (selector) {
+    let element = this
+
+    do {
+      if (matches.call(element, selector)) {
+        return element
+      }
+
+      element = element.parentElement || element.parentNode
+    } while (element !== null && element.nodeType === 1)
+
+    return null
+  }
+}
+
+const scopeSelectorRegex = /:scope\b/
+const supportScopeQuery = (() => {
+  const element = document.createElement('div')
+
+  try {
+    element.querySelectorAll(':scope *')
+  } catch (error) {
+    return false
+  }
+
+  return true
+})()
+
+if (!supportScopeQuery) {
+  find = function (selector) {
+    if (!scopeSelectorRegex.test(selector)) {
+      return this.querySelectorAll(selector)
+    }
+
+    const hasId = Boolean(this.id)
+
+    if (!hasId) {
+      this.id = getUID('scope')
+    }
+
+    let nodeList = null
+    try {
+      selector = selector.replace(scopeSelectorRegex, `#${this.id}`)
+      nodeList = this.querySelectorAll(selector)
+    } finally {
+      if (!hasId) {
+        this.removeAttribute('id')
+      }
+    }
+
+    return nodeList
+  }
+
+  findOne = function (selector) {
+    if (!scopeSelectorRegex.test(selector)) {
+      return this.querySelector(selector)
+    }
+
+    const matches = find.call(this, selector)
+
+    if (typeof matches[0] !== 'undefined') {
+      return matches[0]
+    }
+
+    return null
+  }
+}
+
+export {
+  createCustomEvent,
+  find,
+  findOne,
+  matches,
+  closest,
+  defaultPreventedPreservedOnDispatch
+}

js/src/dom/selectorEngine.js

@@ -5,7 +5,7 @@
  * --------------------------------------------------------------------------
  */
 
-import Polyfill from './polyfill'
+import { find as findFn, findOne, matches, closest } from './polyfill'
 import { makeArray } from '../util/index'
 
 /**
@@ -14,12 +14,11 @@ import { makeArray } from '../util/index'
  * ------------------------------------------------------------------------
  */
 
-const { find: findFn, findOne } = Polyfill
 const NODE_TEXT = 3
 
 const SelectorEngine = {
   matches(element, selector) {
-    return element.matches(selector)
+    return matches.call(element, selector)
   },
 
   find(selector, element = document.documentElement) {
@@ -72,7 +71,7 @@ const SelectorEngine = {
       return null
     }
 
-    return element.closest(selector)
+    return closest.call(element, selector)
   },
 
   prev(element, selector) {