Set defaults in constructor, in case opts are undefined.

app/assets/javascripts/blob/blob_ci_yaml.js.es6

@@ -14,9 +14,9 @@
   global.BlobCiYamlSelector = BlobCiYamlSelector;
 
   class BlobCiYamlSelectors {
-    constructor({ editor, $dropdowns = $('.js-gitlab-ci-yml-selector') }) {
+    constructor({ editor, $dropdowns }) {
       this.editor = editor;
-      this.$dropdowns = $dropdowns;
+      this.$dropdowns = $dropdowns || $('.js-gitlab-ci-yml-selector');
       this.initSelectors();
     }
 

app/assets/javascripts/profile/profile.js.es6

 ((global) => {
 
   class Profile {
-    constructor({ form = $('.edit-user') } = {}) {
+    constructor({ form }) {
       this.onSubmitForm = this.onSubmitForm.bind(this);
-      this.form = form;
+      this.form = form || $('.edit-user');
       this.bindEvents();
       this.initAvatarGlCrop();
     }

app/assets/javascripts/search_autocomplete.js.es6

@@ -9,20 +9,13 @@
   };
 
   class SearchAutocomplete {
-    constructor({
-      wrap = $('.search'),
-      optsEl = wrap.find('.search-autocomplete-opts'),
-      autocompletePath = optsEl.data('autocomplete-path'),
-      projectId = (optsEl.data('autocomplete-project-id') || ''),
-      projectRef = (optsEl.data('autocomplete-project-ref') || '')
-    } = {}) {
-
+    constructor({ wrap, optsEl, autocompletePath, projectId, projectRef }) {
       this.bindEventContext();
-      this.wrap = wrap;
-      this.optsEl = optsEl;
-      this.autocompletePath = autocompletePath;
-      this.projectId = projectId;
-      this.projectRef = projectRef;
+      this.wrap = wrap || $('.search');
+      this.optsEl = optsEl || wrap.find('.search-autocomplete-opts');
+      this.autocompletePath = autocompletePath || optsEl.data('autocomplete-path');
+      this.projectId = projectId || (optsEl.data('autocomplete-project-id') || '');
+      this.projectRef = projectRef || (optsEl.data('autocomplete-project-ref') || '');
       this.dropdown = wrap.find('.dropdown');
       this.dropdownContent = this.dropdown.find('.dropdown-content');
       this.locationBadgeEl = this.getElement('.location-badge');

app/assets/javascripts/todos.js.es6

 ((global) => {
 
   class Todos {
-    constructor({ el = $('.js-todos-options') }) {
+    constructor({ el }) {
       this.allDoneClicked = this.allDoneClicked.bind(this);
       this.doneClicked = this.doneClicked.bind(this);
-      this.el = el;
+      this.el = el || $('.js-todos-options');
       this.perPage = el.data('perPage');
       this.clearListeners();
       this.initBtnListeners();

app/assets/javascripts/user_tabs.js.es6

@@ -59,10 +59,10 @@ content on the Users#show page.
 */
 ((global) => {
   class UserTabs {
-    constructor ({ defaultAction = 'activity', action = defaultAction, parentEl }) {
+    constructor ({ defaultAction, action, parentEl }) {
       this.loaded = {};
-      this.defaultAction = defaultAction;
-      this.action = action;
+      this.defaultAction = defaultAction || 'activity';
+      this.action = action || this.defaultAction;
       this.$parentEl = $(parentEl) || $(document);
       this._location = window.location;
       this.$parentEl.find('.nav-links a')