diff --git a/core/lib/Drupal/Core/Datetime/DateFormatter.php b/core/lib/Drupal/Core/Datetime/DateFormatter.php
index 40b8621..5e81fce 100644
--- a/core/lib/Drupal/Core/Datetime/DateFormatter.php
+++ b/core/lib/Drupal/Core/Datetime/DateFormatter.php
@@ -211,14 +211,14 @@ public function formatInterval($interval, $granularity = 2, $langcode = NULL) {
    */
   public function getSampleDateFormats($langcode = NULL, $timestamp = NULL, $timezone = NULL) {
     $language_code = $langcode ?: NULL;
-    $ts = $timestamp ?: REQUEST_TIME;
-    $tz = $timezone ?: NULL;
+    $timestamp = $timestamp ?: REQUEST_TIME;
+    $timezone = $timezone ?: NULL;
     // All date format characters for the PHP date() function.
     $date_characters = 'dDjlNSwzWFmMntLoYyaABgGhHisueIOPTZcrU';
     $date_chars = str_split($date_characters);
     $date_elements = array_combine($date_chars, $date_chars);
-    return array_map(function($character) use ($ts, $tz, $language_code) {
-      return $this->format($ts, 'custom', $character, $tz, $language_code);
+    return array_map(function($character) use ($timestamp, $timezone, $language_code) {
+      return $this->format($timestamp, 'custom', $character, $timezone, $language_code);
     }, $date_elements);
   }
 
diff --git a/core/modules/config_translation/src/FormElement/DateFormat.php b/core/modules/config_translation/src/FormElement/DateFormat.php
index b541108..45aab74 100644
--- a/core/modules/config_translation/src/FormElement/DateFormat.php
+++ b/core/modules/config_translation/src/FormElement/DateFormat.php
@@ -27,29 +27,24 @@ public function getTranslationElement(LanguageInterface $translation_language, $
     $description = $this->t('A user-defined date format. See the <a href="@url">PHP manual</a> for available options.', array('@url' => 'http://php.net/manual/function.date.php'));
     $format = $this->t('Displayed as %date_format', array('%date_format' => $date_formatter->format(REQUEST_TIME, 'custom', $translation_config)));
 
-    return array(
+    return [
       '#type' => 'textfield',
       '#description' => $description,
       '#field_suffix' => ' <small data-drupal-date-formatter="preview">' . $format . '</small>',
-      '#attributes' => array(
+      '#attributes' => [
         'data-drupal-date-formatter' => 'source',
-      ),
-      '#attached' => array(
+      ],
+      '#attached' => [
         'drupalSettings' => array('dateFormats' => $date_formatter->getSampleDateFormats($translation_language->getId())),
-      ),
-
-    ) + parent::getTranslationElement($translation_language, $source_config, $translation_config);
+      ],
+    ] + parent::getTranslationElement($translation_language, $source_config, $translation_config);
   }
 
   /**
    * {@inheritdoc}
    */
   public function getFormAttributes() {
-    return array(
-      '#attached' => array(
-        'library' => array('system/drupal.system.date'),
-      ),
-    );
+    return ['#attached' => ['library' => ['system/drupal.system.date']]];
   }
 
 }
diff --git a/core/modules/system/js/system.date.js b/core/modules/system/js/system.date.js
index 98bb96e..fcab3ef 100644
--- a/core/modules/system/js/system.date.js
+++ b/core/modules/system/js/system.date.js
@@ -22,7 +22,7 @@
       /**
        * Event handler that replaces date characters with value.
        *
-       * @param Object e
+       * @param {object} e
        */
       function dateFormatHandler(e) {
         var baseValue = $(e.target).val() || '';