Avoid warnings when a content type is not configured

node_authlink.module

@@ -22,6 +22,10 @@ function node_authlink_form_node_type_form_alter(&$form, FormStateInterface &$fo
   $type = $node_type->getEntity()->id();
   $config = \Drupal::config('node_authlink.settings');
 
+  $config_enable = $config->get('enable');
+  $config_grants = $config->get('grants');
+  $config_expire = $config->get('expire');
+
   $form['node_authlink'] = [
     '#type' => 'details',
     '#title' => t('Node authorize link'),
@@ -31,14 +35,14 @@ function node_authlink_form_node_type_form_alter(&$form, FormStateInterface &$fo
   $form['node_authlink']['node_authlink_enable'] = [
     '#type' => 'checkbox',
     '#title' => t('Enable'),
-    '#default_value' => $config->get('enable.' . $type),
+    '#default_value' => isset($config_enable[$type])? $config_enable[$type] : 0,
     '#description' => t('Disable of this feature will cost erase of authorization keys of all nodes in this node type.'),
   ];
 
   $form['node_authlink']['node_authlink_grants'] = [
     '#type' => 'checkboxes',
     '#title' => t('Grants to give'),
-    '#default_value' => $config->get('grants.' . $type),
+    '#default_value' => isset($config_grants[$type])? $config_grants[$type] : [],
     '#options' => [
       'view' => t('View'),
       'update' => t('Update'),
@@ -55,7 +59,7 @@ function node_authlink_form_node_type_form_alter(&$form, FormStateInterface &$fo
   $form['node_authlink']['node_authlink_expire'] = [
     '#type' => 'select',
     '#title' => t('Regenerate authkeys after'),
-    '#default_value' => $config->get('expire.' . $type),
+    '#default_value' => isset($config_expire[$type])? $config_expire[$type] : '',
     '#options' => $period,
     '#description' => t('Keys older than selected time will be regenerated by cron run.'),
   ];