Add webform_vat_number submodule

Closes #3465230

modules/webform_vat_number/src/Plugin/WebformElement/VatNumber.php

+<?php
+
+namespace Drupal\webform_vat_number\Plugin\WebformElement;
+
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\webform\Plugin\WebformElementBase;
+use Drupal\webform\WebformInterface;
+use Drupal\webform\WebformSubmissionInterface;
+
+/**
+ * Provides a VAT number element.
+ *
+ * @WebformElement(
+ *   id = "vat_number",
+ *   label = @Translation("VAT number"),
+ *   description = @Translation("Provides a form element for entering a VAT number."),
+ *   category = @Translation("Advanced elements"),
+ *   dependencies = {
+ *     "vat_number",
+ *   }
+ * )
+ */
+class VatNumber extends WebformElementBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getDefaultProperties() {
+    return parent::getDefaultProperties() + [
+      'validate_vies' => TRUE,
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function form(array $form, FormStateInterface $form_state) {
+    $form = parent::form($form, $form_state);
+
+    $form['validation']['validate_vies'] = [
+      '#type' => 'checkbox',
+      '#title' => $this->t('Validate against VIES database'),
+      '#description' => $this->t('If checked, the entered VAT number will be validated against the European VIES VAT database.'),
+    ];
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function prepare(array &$element, ?WebformSubmissionInterface $webform_submission = NULL) {
+    if ($webform_submission->getWebform()->getOperation() === 'test') {
+      $element['#validate_vies'] = FALSE;
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getTestValues(array $element, WebformInterface $webform, array $options = []) {
+    return [
+      'ATU99999999',
+      'BE0999999999',
+      'BG999999999',
+      'CY99999999L',
+      'CZ99999999',
+      'CZ999999999',
+      'DE999999999',
+      'DK99999999',
+      'EE999999999',
+      'EL999999999',
+      'ESX9999999X',
+      'FI99999999',
+      'FRXX999999999',
+      'GB999999999',
+      'GB999999999999',
+      'GBGD999',
+      'HR99999999999',
+      'HU99999999',
+      'IE9S99999L',
+      'IT99999999999',
+      'LT999999999',
+      'LU99999999',
+      'LV99999999999',
+      'MT99999999',
+      'NL999999999B99',
+      'PL9999999999',
+      'PT999999999',
+      'RO999999999',
+      'SE999999999999',
+      'SI99999999',
+      'SK9999999999',
+    ];
+  }
+
+}