Issue #3387807 by d.clarke: HTML 5 data-* attributes fix for case sensitive variable names

src/Plugin/Field/FieldWidget/SignWidget.php

@@ -3,11 +3,11 @@
 namespace Drupal\sign_widget\Plugin\Field\FieldWidget;
 
 use Drupal\Component\Render\PlainTextOutput;
+use Drupal\Component\Utility\Html;
 use Drupal\Core\Field\FieldItemListInterface;
 use Drupal\Core\Field\FieldStorageDefinitionInterface;
 use Drupal\Core\File\FileSystemInterface;
 use Drupal\Core\Form\FormStateInterface;
-use Drupal\Component\Utility\Html;
 use Drupal\Core\Template\Attribute;
 use Drupal\file\Entity\File;
 use Drupal\image\Plugin\Field\FieldWidget\ImageWidget;
@@ -229,7 +229,7 @@ class SignWidget extends ImageWidget {
       'class' => ["signature-pad", "border"],
     ]);
     foreach ($this->settings as $attribute => $settingValue) {
-      $attributes['data-' . $attribute] = $settingValue;
+      $attributes['data-' . strtolower(preg_replace('/([a-zA-Z])(?=[A-Z])/', '$1-', $attribute))] = $settingValue;
     }
     $sign_pad = [
       '#theme' => 'sign',