diff --git a/js/src/collapse.js b/js/src/collapse.js
index c3b3599ecc..e22cf0b7ab 100644
--- a/js/src/collapse.js
+++ b/js/src/collapse.js
@@ -331,7 +331,7 @@ const Collapse = (($) => {
         const _config = {
           ...Default,
           ...$this.data(),
-          ...typeof config === 'object' && config
+          ...typeof config === 'object' && config ? config : {}
         }
 
         if (!data && _config.toggle && /show|hide/.test(config)) {
diff --git a/js/src/modal.js b/js/src/modal.js
index 1df4152666..e3de68b8fe 100644
--- a/js/src/modal.js
+++ b/js/src/modal.js
@@ -500,7 +500,7 @@ const Modal = (($) => {
         const _config = {
           ...Default,
           ...$(this).data(),
-          ...typeof config === 'object' && config
+          ...typeof config === 'object' && config ? config : {}
         }
 
         if (!data) {
diff --git a/js/src/scrollspy.js b/js/src/scrollspy.js
index 1c46940f53..d8cf69473b 100644
--- a/js/src/scrollspy.js
+++ b/js/src/scrollspy.js
@@ -165,7 +165,7 @@ const ScrollSpy = (($) => {
     _getConfig(config) {
       config = {
         ...Default,
-        ...config
+        ...typeof config === 'object' && config ? config : {}
       }
 
       if (typeof config.target !== 'string') {
diff --git a/js/src/tooltip.js b/js/src/tooltip.js
index f751ee3c94..59c26897c9 100644
--- a/js/src/tooltip.js
+++ b/js/src/tooltip.js
@@ -611,7 +611,7 @@ const Tooltip = (($) => {
       config = {
         ...this.constructor.Default,
         ...$(this.element).data(),
-        ...config
+        ...typeof config === 'object' && config ? config : {}
       }
 
       if (typeof config.delay === 'number') {
diff --git a/js/tests/unit/dropdown.js b/js/tests/unit/dropdown.js
index 726655e9cc..f87c65bea0 100644
--- a/js/tests/unit/dropdown.js
+++ b/js/tests/unit/dropdown.js
@@ -544,6 +544,41 @@ $(function () {
     $dropdown.trigger('click')
   })
 
+  QUnit.test('should skip disabled element when using keyboard navigation', function (assert) {
+    assert.expect(3)
+    var done = assert.async()
+    var dropdownHTML = '<div class="tabs">' +
+        '<div class="dropdown">' +
+        '<a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown</a>' +
+        '<div class="dropdown-menu">' +
+        '<a class="dropdown-item disabled" href="#">Disabled link</a>' +
+        '<button class="dropdown-item" type="button" disabled>Disabled button</button>' +
+        '<a id="item1" class="dropdown-item" href="#">Another link</a>' +
+        '</div>' +
+        '</div>' +
+        '</div>'
+    var $dropdown = $(dropdownHTML)
+      .appendTo('#qunit-fixture')
+      .find('[data-toggle="dropdown"]')
+      .bootstrapDropdown()
+
+    $dropdown
+      .parent('.dropdown')
+      .on('shown.bs.dropdown', function () {
+        assert.ok(true, 'shown was fired')
+        $dropdown.trigger($.Event('keydown', {
+          which: 40
+        }))
+        $dropdown.trigger($.Event('keydown', {
+          which: 40
+        }))
+        assert.ok(!$(document.activeElement).is('.disabled'), '.disabled is not focused')
+        assert.ok(!$(document.activeElement).is(':disabled'), ':disabled is not focused')
+        done()
+      })
+    $dropdown.trigger('click')
+  })
+
   QUnit.test('should focus next/previous element when using keyboard navigation', function (assert) {
     assert.expect(4)
     var done = assert.async()
@@ -584,41 +619,6 @@ $(function () {
     $dropdown.trigger('click')
   })
 
-  QUnit.test('should skip disabled element when using keyboard navigation', function (assert) {
-    assert.expect(3)
-    var done = assert.async()
-    var dropdownHTML = '<div class="tabs">' +
-        '<div class="dropdown">' +
-        '<a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown</a>' +
-        '<div class="dropdown-menu">' +
-        '<a class="dropdown-item disabled" href="#">Disabled link</a>' +
-        '<button class="dropdown-item" type="button" disabled>Disabled button</button>' +
-        '<a id="item1" class="dropdown-item" href="#">Another link</a>' +
-        '</div>' +
-        '</div>' +
-        '</div>'
-    var $dropdown = $(dropdownHTML)
-      .appendTo('#qunit-fixture')
-      .find('[data-toggle="dropdown"]')
-      .bootstrapDropdown()
-
-    $dropdown
-      .parent('.dropdown')
-      .on('shown.bs.dropdown', function () {
-        assert.ok(true, 'shown was fired')
-        $dropdown.trigger($.Event('keydown', {
-          which: 40
-        }))
-        assert.ok($(document.activeElement).is($('#item1')), '#item1 is focused')
-        $dropdown.trigger($.Event('keydown', {
-          which: 40
-        }))
-        assert.ok($(document.activeElement).is($('#item1')), '#item1 is still focused')
-        done()
-      })
-    $dropdown.trigger('click')
-  })
-
   QUnit.test('should not close the dropdown if the user clicks on a text field', function (assert) {
     assert.expect(2)
     var done = assert.async()