[4.0] ES6 please, com newsfeed (#21433)

* com_newsfeed

* woof

* woof ?

Author: dGrammatiko

build/media/com_newsfeeds/js/categories-default.js

@@ -0,0 +1,46 @@
+/**
+ * @copyright  Copyright (C) 2005 - 2018 Open Source Matters, Inc. All rights reserved.
+ * @license    GNU General Public License version 2 or later; see LICENSE.txt
+ */
+((JText) => {
+  'use strict';
+
+  // Selectors used by this script
+  const buttonsSelector = '[id^=category-btn-]';
+
+  /**
+   * Handle the category toggle button click event
+   * @param event
+   */
+  const handleCategoryToggleButtonClick = (event) => {
+    const button = event.currentTarget;
+    const icon = button.querySelector('span');
+
+    // Toggle icon class
+    icon.classList.toggle('icon-plus');
+    icon.classList.toggle('icon-minus');
+
+    // Toggle aria label
+    const ariaLabel = button.getAttribute('aria-label');
+    button.setAttribute(
+      'aria-label',
+      (ariaLabel === JText._('JGLOBAL_COLLAPSE_CATEGORIES')
+        || JText._('JGLOBAL_EXPAND_CATEGORIES')),
+    );
+  };
+
+  /**
+   * Register the events
+   */
+  const registerEvents = () => {
+    const buttons = [].slice.call(document.querySelectorAll(buttonsSelector));
+    buttons.forEach((button) => {
+      button.addEventListener('click', handleCategoryToggleButtonClick);
+    });
+
+    // Cleanup
+    document.removeEventListener('DOMContentLoaded', registerEvents);
+  };
+
+  document.addEventListener('DOMContentLoaded', registerEvents);
+})(Joomla.JText);