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

core/lib/Drupal/Component/Serialization/Json.php

@@ -0,0 +1,41 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Component\Serialization\Json.
+ */
+
+namespace Drupal\Component\Serialization;
+
+/**
+ * Default serialization for JSON.
+ *
+ * @ingroup third_party
+ */
+class Json implements SerializationInterface {
+
+  /**
+   * {@inheritdoc}
+   *
+   * Uses HTML-safe strings, with several characters escaped.
+   */
+  public static function encode($variable) {
+    // Encode <, >, ', &, and ".
+    return json_encode($variable, JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_AMP | JSON_HEX_QUOT);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function decode($string) {
+    return json_decode($string, TRUE);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getFileExtension() {
+    return 'json';
+  }
+
+}