dropdown - destroy old popper.js references

js/src/dropdown/dropdown.js

@@ -155,10 +155,6 @@ class Dropdown {
 
     // Disable totally Popper.js for Dropdown in Navbar
     if (!this._inNavbar) {
-      /**
-       * Check for Popper dependency
-       * Popper - https://popper.js.org
-       */
       if (typeof Popper === 'undefined') {
         throw new TypeError('Bootstrap\'s dropdowns require Popper.js (https://popper.js.org)')
       }
@@ -251,7 +247,7 @@ class Dropdown {
     EventHandler.off(this._element, EVENT_KEY)
     this._element = null
     this._menu = null
-    if (this._popper !== null) {
+    if (this._popper) {
       this._popper.destroy()
       this._popper = null
     }
@@ -259,7 +255,7 @@ class Dropdown {
 
   update() {
     this._inNavbar = this._detectNavbar()
-    if (this._popper !== null) {
+    if (this._popper) {
       this._popper.scheduleUpdate()
     }
   }
@@ -440,6 +436,10 @@ class Dropdown {
 
       toggles[i].setAttribute('aria-expanded', 'false')
 
+      if (context._popper) {
+        context._popper.destroy()
+      }
+
       dropdownMenu.classList.remove(ClassName.SHOW)
       parent.classList.remove(ClassName.SHOW)
       EventHandler.trigger(parent, Event.HIDDEN, relatedTarget)

js/src/dropdown/dropdown.spec.js

@@ -147,6 +147,44 @@ describe('Dropdown', () => {
       dropdown.toggle()
     })
 
+    it('should destroy old popper references on toggle', done => {
+      fixtureEl.innerHTML = [
+        '<div class="first dropdown">',
+        '  <button href="#" class="firstBtn btn" data-toggle="dropdown" aria-expanded="false">Dropdown</button>',
+        '  <div class="dropdown-menu">',
+        '    <a class="dropdown-item" href="#">Secondary link</a>',
+        '  </div>',
+        '</div>',
+        '<div class="second dropdown">',
+        '  <button href="#" class="secondBtn btn" data-toggle="dropdown" aria-expanded="false">Dropdown</button>',
+        '  <div class="dropdown-menu">',
+        '    <a class="dropdown-item" href="#">Secondary link</a>',
+        '  </div>',
+        '</div>'
+      ].join('')
+
+      const btnDropdown1 = fixtureEl.querySelector('.firstBtn')
+      const btnDropdown2 = fixtureEl.querySelector('.secondBtn')
+      const firstDropdownEl = fixtureEl.querySelector('.first')
+      const secondDropdownEl = fixtureEl.querySelector('.second')
+      const dropdown1 = new Dropdown(btnDropdown1)
+      const dropdown2 = new Dropdown(btnDropdown2)
+
+      firstDropdownEl.addEventListener('shown.bs.dropdown', () => {
+        expect(firstDropdownEl.classList.contains('show')).toEqual(true)
+        spyOn(dropdown1._popper, 'destroy')
+        dropdown2.toggle()
+        done()
+      })
+
+      secondDropdownEl.addEventListener('shown.bs.dropdown', () => {
+        expect(dropdown1._popper.destroy).toHaveBeenCalled()
+        done()
+      })
+
+      dropdown1.toggle()
+    })
+
     it('should toggle a dropdown and add/remove event listener on mobile', done => {
       fixtureEl.innerHTML = [
         '<div class="dropdown">',