Issue #2920956 by hgoto: Add the function and UI to change the versions.

includes/vuejs.admin.inc

+<?php
+
+/**
+ * @file
+ * Provides admin page callbacks for vuejs module.
+ */
+
+/**
+ * Form builder for admin/config/development/vuejs.
+ */
+function vuejs_settings_form($form, &$form_state) {
+  $libraries = array(
+    'vue' => array(
+      'default' => 'v2.5.2',
+    ),
+    'vue_router' => array(
+      'default' => 'v3.0.1',
+    ),
+    'vuex' => array(
+      'default' => 'v3.0.0',
+    ),
+  );
+
+  foreach ($libraries as $library_name => $versions) {
+    $variable_name = 'vuejs_version_' . $library_name;
+
+    $current_version = variable_get($variable_name, $versions['default']);
+
+    $form[$library_name] = array(
+      '#type' => 'fieldset',
+      '#title' => str_replace('_', '-', $library_name),
+    );
+
+    $form[$library_name][$variable_name] = array(
+      '#type' => 'textfield',
+      '#title' => t('Version'),
+      '#size' => 9,
+      '#required' => TRUE,
+      '#default_value' => $current_version,
+      '#description' => t('The defaule version is "@version".', array(
+        '@version' => $versions['default'],
+      )),
+      '#element_validate' => array('vuejs_validate_version_text'),
+    );
+  }
+
+  $form['#submit'][] = 'vuejs_settings_form_submit';
+
+  return system_settings_form($form);
+}
+
+/**
+ * Additional submit callback for vuejs_settings_form().
+ */
+function vuejs_settings_form_submit(&$form, &$form_state) {
+  libraries_cache_clear();
+}

vuejs.module

@@ -80,6 +80,33 @@ function vuejs_libraries_info() {
   return $libraries;
 }
 
+/**
+ * Implements hook_permission().
+ */
+function vuejs_permission() {
+  return array(
+    'administer vuejs configuration' => array(
+      'title' => t('Administer vuejs configuration'),
+      'restrict access' => TRUE,
+    ),
+  );
+}
+
+/**
+ * Implements hook_menu().
+ */
+function vuejs_menu() {
+  $items['admin/config/development/vuejs'] = array(
+    'title' => 'Vue.js',
+    'page callback' => 'drupal_get_form',
+    'page arguments' => array('vuejs_settings_form'),
+    'access arguments' => array('administer vuejs configuration'),
+    'file' => 'includes/vuejs.admin.inc',
+  );
+
+  return $items;
+}
+
 /**
  * Theme functions.
  */
@@ -91,3 +118,18 @@ function vuejs_libraries_info() {
 /**
  * Other functions.
  */
+
+/**
+ * Validator function for text fields for versions.
+ *
+ * @see vuejs_settings_form()
+ */
+function vuejs_validate_version_text($element, &$form_state, $form) {
+  if (!empty($element['#value'])) {
+    $value = $element['#value'];
+    $result = preg_match('/^v?[\d\.]+$/', $value);
+    if (empty($result)) {
+      form_error($element, t('The version is not valid.'));
+    }
+  }
+}