Drupal 8.0.0 beta 12. More info: https://www.drupal.org/node/2514176

core/modules/rdf/src/CommonDataConverter.php

@@ -0,0 +1,40 @@
+<?php
+/**
+ * @file
+ * Contains \Drupal\rdf\CommonDataConverter.
+ */
+
+namespace Drupal\rdf;
+
+/**
+ * Contains methods for common data conversions.
+ */
+class CommonDataConverter {
+
+  /**
+   * Provides a passthrough to place unformatted values in content attributes.
+   *
+   * @param mixed $data
+   *   The data to be placed in the content attribute.
+   *
+   * @return mixed
+   *   Returns the data.
+   */
+  public static function rawValue($data) {
+    return $data;
+  }
+
+  /**
+   * Converts a date entity field array into an ISO 8601 timestamp string.
+   *
+   * @param array $data
+   *   The array containing the 'value' element.
+   *
+   * @return string
+   *   Returns the ISO 8601 timestamp.
+   */
+  public static function dateIso8601Value($data) {
+    return date_iso8601($data['value']);
+  }
+
+}