primo commit

media/com_modules/js/admin-module-edit_assignment.js

@@ -0,0 +1,30 @@
+/**
+ * @copyright  (C) 2018 Open Source Matters, Inc. <https://www.joomla.org>
+ * @license    GNU General Public License version 2 or later; see LICENSE.txt
+ */
+(() => {
+
+  const onChange = value => {
+    if (value === '-' || parseInt(value, 10) === 0) {
+      document.getElementById('menuselect-group').classList.add('hidden');
+    } else {
+      document.getElementById('menuselect-group').classList.remove('hidden');
+    }
+  };
+  const onBoot = () => {
+    const element = document.getElementById('jform_assignment');
+    if (element) {
+      // Initialise the state
+      onChange(element.value);
+
+      // Check for changes in the state
+      element.addEventListener('change', ({
+        target
+      }) => {
+        onChange(target.value);
+      });
+    }
+    document.removeEventListener('DOMContentLoaded', onBoot);
+  };
+  document.addEventListener('DOMContentLoaded', onBoot);
+})();