add theme config option + add config schema

config/install/yaml_editor.config.yml

@@ -1 +1,2 @@
 editor_source: //cdnjs.cloudflare.com/ajax/libs/ace/1.2.0/ace.min.js
+editor_theme: ace/theme/chrome

config/schema/yaml_editor.schema.yml

@@ -0,0 +1,10 @@
+yaml_editor.config:
+  type: config_object
+  label: 'Yaml Editor Config'
+  mapping:
+    editor_source:
+      type: string
+      label: 'Editor source'
+    editor_theme:
+      type: string
+      label: 'Editor theme'

js/yaml-editor.js

@@ -16,7 +16,7 @@
           editor.getSession().setValue($textarea.val());
           editor.getSession().setMode('ace/mode/yaml');
           editor.getSession().setTabSize(2);
-          editor.setTheme('ace/theme/chrome');
+          editor.setTheme(drupalSettings.yamlEditor.theme);
           editor.setOptions({
             minLines: 3,
             maxLines: 20

src/Form/ConfigForm.php

@@ -46,6 +46,13 @@ public function buildForm(array $form, FormStateInterface $form_state) {
       '#default_value' => $config->get('editor_source'),
     ];
 
+    $form['editor_theme'] = [
+      '#type' => 'textfield',
+      '#title' => $this->t('Editor theme'),
+      '#description' => $this->t('Enter name of Ace theme to use.'),
+      '#default_value' => $config->get('editor_theme'),
+    ];
+
     return parent::buildForm($form, $form_state);
   }
 
@@ -61,9 +68,11 @@ public function validateForm(array &$form, FormStateInterface $form_state) {
    */
   public function submitForm(array &$form, FormStateInterface $form_state) {
     $editor_source = $form_state->getValue('editor_source');
+    $editor_theme = $form_state->getValue('editor_theme');
 
     $this->config('yaml_editor.config')
       ->set('editor_source', $editor_source)
+      ->set('editor_theme', $editor_theme)
       ->save();
 
     parent::submitForm($form, $form_state);

yaml_editor.install

@@ -0,0 +1,11 @@
+<?php
+
+/**
+ * Set default editor_theme in config.
+ */
+function yaml_editor_update_8001() {
+  \Drupal::configFactory()
+    ->getEditable('yaml_editor.config')
+    ->set('editor_theme', 'ace/theme/chrome')
+    ->save(TRUE);
+}

yaml_editor.module

@@ -8,9 +8,12 @@ function yaml_editor_page_attachments(array &$attachments) {
   $is_admin = \Drupal::service('router.admin_context')->isAdminRoute($route);
 
   if ($is_admin) {
-    $source = \Drupal::config('yaml_editor.config')->get('editor_source');
+    $config = \Drupal::config('yaml_editor.config');
+    $source = $config->get('editor_source');
+    $theme = $config->get('editor_theme');
 
     $attachments['#attached']['drupalSettings']['yamlEditor']['source'] = $source;
+    $attachments['#attached']['drupalSettings']['yamlEditor']['theme'] = $theme;
     $attachments['#attached']['library'][] = 'yaml_editor/yaml_editor';
   }
 }