Fix handling of transitionend events dispatched by nested elements(#33845)

Fix handling of transitionend events dispatched by nested elements
Properly handle events from nested elements

Change `emulateTransitionEnd` to `executeAfterTransition` &&

js/src/base-component.js

@@ -7,10 +7,8 @@
 
 import Data from './dom/data'
 import {
-  emulateTransitionEnd,
-  execute,
-  getElement,
-  getTransitionDurationFromElement
+  executeAfterTransition,
+  getElement
 } from './util/index'
 import EventHandler from './dom/event-handler'
 
@@ -44,15 +42,7 @@ class BaseComponent {
   }
 
   _queueCallback(callback, element, isAnimated = true) {
-    if (!isAnimated) {
-      execute(callback)
-      return
-    }
-
-    const transitionDuration = getTransitionDurationFromElement(element)
-    EventHandler.one(element, 'transitionend', () => execute(callback))
-
-    emulateTransitionEnd(element, transitionDuration)
+    executeAfterTransition(callback, element, isAnimated)
   }
 
   /** Static */

js/src/modal.js

@@ -7,9 +7,7 @@
 
 import {
   defineJQueryPlugin,
-  emulateTransitionEnd,
   getElementFromSelector,
-  getTransitionDurationFromElement,
   isRTL,
   isVisible,
   reflow,
@@ -339,25 +337,28 @@ class Modal extends BaseComponent {
       return
     }
 
-    const isModalOverflowing = this._element.scrollHeight > document.documentElement.clientHeight
+    const { classList, scrollHeight, style } = this._element
+    const isModalOverflowing = scrollHeight > document.documentElement.clientHeight
 
-    if (!isModalOverflowing) {
-      this._element.style.overflowY = 'hidden'
+    // return if the following background transition hasn't yet completed
+    if ((!isModalOverflowing && style.overflowY === 'hidden') || classList.contains(CLASS_NAME_STATIC)) {
+      return
     }
 
-    this._element.classList.add(CLASS_NAME_STATIC)
-    const modalTransitionDuration = getTransitionDurationFromElement(this._dialog)
-    EventHandler.off(this._element, 'transitionend')
-    EventHandler.one(this._element, 'transitionend', () => {
-      this._element.classList.remove(CLASS_NAME_STATIC)
+    if (!isModalOverflowing) {
+      style.overflowY = 'hidden'
+    }
+
+    classList.add(CLASS_NAME_STATIC)
+    this._queueCallback(() => {
+      classList.remove(CLASS_NAME_STATIC)
       if (!isModalOverflowing) {
-        EventHandler.one(this._element, 'transitionend', () => {
-          this._element.style.overflowY = ''
-        })
-        emulateTransitionEnd(this._element, modalTransitionDuration)
+        this._queueCallback(() => {
+          style.overflowY = ''
+        }, this._dialog)
       }
-    })
-    emulateTransitionEnd(this._element, modalTransitionDuration)
+    }, this._dialog)
+
     this._element.focus()
   }
 

js/src/util/backdrop.js

@@ -6,7 +6,7 @@
  */
 
 import EventHandler from '../dom/event-handler'
-import { emulateTransitionEnd, execute, getElement, getTransitionDurationFromElement, reflow, typeCheckConfig } from './index'
+import { execute, executeAfterTransition, getElement, reflow, typeCheckConfig } from './index'
 
 const Default = {
   isVisible: true, // if false, we use the backdrop helper without adding any element to the dom
@@ -122,14 +122,7 @@ class Backdrop {
   }
 
   _emulateAnimation(callback) {
-    if (!this._config.isAnimated) {
-      execute(callback)
-      return
-    }
-
-    const backdropTransitionDuration = getTransitionDurationFromElement(this._getElement())
-    EventHandler.one(this._getElement(), 'transitionend', () => execute(callback))
-    emulateTransitionEnd(this._getElement(), backdropTransitionDuration)
+    executeAfterTransition(callback, this._getElement(), this._config.isAnimated)
   }
 }
 

js/src/util/index.js

@@ -126,24 +126,6 @@ const getElement = obj => {
   return null
 }
 
-const emulateTransitionEnd = (element, duration) => {
-  let called = false
-  const durationPadding = 5
-  const emulatedDuration = duration + durationPadding
-
-  function listener() {
-    called = true
-    element.removeEventListener(TRANSITION_END, listener)
-  }
-
-  element.addEventListener(TRANSITION_END, listener)
-  setTimeout(() => {
-    if (!called) {
-      triggerTransitionEnd(element)
-    }
-  }, emulatedDuration)
-}
-
 const typeCheckConfig = (componentName, config, configTypes) => {
   Object.keys(configTypes).forEach(property => {
     const expectedTypes = configTypes[property]
@@ -252,6 +234,35 @@ const execute = callback => {
   }
 }
 
+const executeAfterTransition = (callback, transitionElement, waitForTransition = true) => {
+  if (!waitForTransition) {
+    execute(callback)
+    return
+  }
+
+  const durationPadding = 5
+  const emulatedDuration = getTransitionDurationFromElement(transitionElement) + durationPadding
+
+  let called = false
+
+  const handler = ({ target }) => {
+    if (target !== transitionElement) {
+      return
+    }
+
+    called = true
+    transitionElement.removeEventListener(TRANSITION_END, handler)
+    execute(callback)
+  }
+
+  transitionElement.addEventListener(TRANSITION_END, handler)
+  setTimeout(() => {
+    if (!called) {
+      triggerTransitionEnd(transitionElement)
+    }
+  }, emulatedDuration)
+}
+
 /**
  * Return the previous/next element of a list.
  *
@@ -288,7 +299,6 @@ export {
   getTransitionDurationFromElement,
   triggerTransitionEnd,
   isElement,
-  emulateTransitionEnd,
   typeCheckConfig,
   isVisible,
   isDisabled,
@@ -300,5 +310,6 @@ export {
   onDOMContentLoaded,
   isRTL,
   defineJQueryPlugin,
-  execute
+  execute,
+  executeAfterTransition
 }

js/tests/unit/modal.spec.js

@@ -539,6 +539,29 @@ describe('Modal', () => {
       modal.show()
     })
 
+    it('should not queue multiple callbacks when clicking outside of modal-content and backdrop = static', done => {
+      fixtureEl.innerHTML = '<div class="modal"><div class="modal-dialog" style="transition-duration: 50ms;"></div></div>'
+
+      const modalEl = fixtureEl.querySelector('.modal')
+      const modal = new Modal(modalEl, {
+        backdrop: 'static'
+      })
+
+      modalEl.addEventListener('shown.bs.modal', () => {
+        const spy = spyOn(modal, '_queueCallback').and.callThrough()
+
+        modalEl.click()
+        modalEl.click()
+
+        setTimeout(() => {
+          expect(spy).toHaveBeenCalledTimes(1)
+          done()
+        }, 20)
+      })
+
+      modal.show()
+    })
+
     it('should enforce focus', done => {
       fixtureEl.innerHTML = '<div class="modal"><div class="modal-dialog"></div></div>'
 

js/tests/unit/tooltip.spec.js

@@ -446,7 +446,7 @@ describe('Tooltip', () => {
       const tooltip = new Tooltip(tooltipEl)
       document.documentElement.ontouchstart = noop
 
-      spyOn(EventHandler, 'on')
+      spyOn(EventHandler, 'on').and.callThrough()
 
       tooltipEl.addEventListener('shown.bs.tooltip', () => {
         expect(document.querySelector('.tooltip')).not.toBeNull()

js/tests/unit/util/index.spec.js

@@ -157,12 +157,13 @@ describe('Util', () => {
 
   describe('triggerTransitionEnd', () => {
     it('should trigger transitionend event', done => {
-      fixtureEl.innerHTML = '<div style="transition: all 300ms ease-out;"></div>'
+      fixtureEl.innerHTML = '<div></div>'
 
       const el = fixtureEl.querySelector('div')
+      const spy = spyOn(el, 'dispatchEvent').and.callThrough()
 
       el.addEventListener('transitionend', () => {
-        expect().nothing()
+        expect(spy).toHaveBeenCalled()
         done()
       })
 
@@ -226,33 +227,6 @@ describe('Util', () => {
     })
   })
 
-  describe('emulateTransitionEnd', () => {
-    it('should emulate transition end', () => {
-      fixtureEl.innerHTML = '<div></div>'
-
-      const el = document.querySelector('div')
-      const spy = spyOn(window, 'setTimeout')
-
-      Util.emulateTransitionEnd(el, 10)
-      expect(spy).toHaveBeenCalled()
-    })
-
-    it('should not emulate transition end if already triggered', done => {
-      fixtureEl.innerHTML = '<div></div>'
-
-      const el = fixtureEl.querySelector('div')
-      const spy = spyOn(el, 'removeEventListener')
-
-      Util.emulateTransitionEnd(el, 10)
-      Util.triggerTransitionEnd(el)
-
-      setTimeout(() => {
-        expect(spy).toHaveBeenCalled()
-        done()
-      }, 20)
-    })
-  })
-
   describe('typeCheckConfig', () => {
     const namePlugin = 'collapse'
 
@@ -660,6 +634,127 @@ describe('Util', () => {
     })
   })
 
+  describe('executeAfterTransition', () => {
+    it('should immediately execute a function when waitForTransition parameter is false', () => {
+      const el = document.createElement('div')
+      const callbackSpy = jasmine.createSpy('callback spy')
+      const eventListenerSpy = spyOn(el, 'addEventListener')
+
+      Util.executeAfterTransition(callbackSpy, el, false)
+
+      expect(callbackSpy).toHaveBeenCalled()
+      expect(eventListenerSpy).not.toHaveBeenCalled()
+    })
+
+    it('should execute a function when a transitionend event is dispatched', () => {
+      const el = document.createElement('div')
+      const callbackSpy = jasmine.createSpy('callback spy')
+
+      spyOn(window, 'getComputedStyle').and.returnValue({
+        transitionDuration: '0.05s',
+        transitionDelay: '0s'
+      })
+
+      Util.executeAfterTransition(callbackSpy, el)
+
+      el.dispatchEvent(new TransitionEvent('transitionend'))
+
+      expect(callbackSpy).toHaveBeenCalled()
+    })
+
+    it('should execute a function after a computed CSS transition duration and there was no transitionend event dispatched', done => {
+      const el = document.createElement('div')
+      const callbackSpy = jasmine.createSpy('callback spy')
+
+      spyOn(window, 'getComputedStyle').and.returnValue({
+        transitionDuration: '0.05s',
+        transitionDelay: '0s'
+      })
+
+      Util.executeAfterTransition(callbackSpy, el)
+
+      setTimeout(() => {
+        expect(callbackSpy).toHaveBeenCalled()
+        done()
+      }, 70)
+    })
+
+    it('should not execute a function a second time after a computed CSS transition duration and if a transitionend event has already been dispatched', done => {
+      const el = document.createElement('div')
+      const callbackSpy = jasmine.createSpy('callback spy')
+
+      spyOn(window, 'getComputedStyle').and.returnValue({
+        transitionDuration: '0.05s',
+        transitionDelay: '0s'
+      })
+
+      Util.executeAfterTransition(callbackSpy, el)
+
+      setTimeout(() => {
+        el.dispatchEvent(new TransitionEvent('transitionend'))
+      }, 50)
+
+      setTimeout(() => {
+        expect(callbackSpy).toHaveBeenCalledTimes(1)
+        done()
+      }, 70)
+    })
+
+    it('should not trigger a transitionend event if another transitionend event had already happened', done => {
+      const el = document.createElement('div')
+
+      spyOn(window, 'getComputedStyle').and.returnValue({
+        transitionDuration: '0.05s',
+        transitionDelay: '0s'
+      })
+
+      Util.executeAfterTransition(() => {}, el)
+
+      // simulate a event dispatched by the browser
+      el.dispatchEvent(new TransitionEvent('transitionend'))
+
+      const dispatchSpy = spyOn(el, 'dispatchEvent').and.callThrough()
+
+      setTimeout(() => {
+        // setTimeout should not have triggered another transitionend event.
+        expect(dispatchSpy).not.toHaveBeenCalled()
+        done()
+      }, 70)
+    })
+
+    it('should ignore transitionend events from nested elements', done => {
+      fixtureEl.innerHTML = [
+        '<div class="outer">',
+        '  <div class="nested"></div>',
+        '</div>'
+      ].join('')
+
+      const outer = fixtureEl.querySelector('.outer')
+      const nested = fixtureEl.querySelector('.nested')
+      const callbackSpy = jasmine.createSpy('callback spy')
+
+      spyOn(window, 'getComputedStyle').and.returnValue({
+        transitionDuration: '0.05s',
+        transitionDelay: '0s'
+      })
+
+      Util.executeAfterTransition(callbackSpy, outer)
+
+      nested.dispatchEvent(new TransitionEvent('transitionend', {
+        bubbles: true
+      }))
+
+      setTimeout(() => {
+        expect(callbackSpy).not.toHaveBeenCalled()
+      }, 20)
+
+      setTimeout(() => {
+        expect(callbackSpy).toHaveBeenCalled()
+        done()
+      }, 70)
+    })
+  })
+
   describe('getNextActiveElement', () => {
     it('should return first element if active not exists or not given and shouldGetNext is either true, or false with cycling being disabled', () => {
       const array = ['a', 'b', 'c', 'd']