diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index e2f3f0751f..f3070315f6 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -6167,6 +6167,26 @@ function wp_is_uuid( $uuid, $version = null ) {
 	return (bool) preg_match( $regex, $uuid );
 }
 
+/**
+ * Get unique ID.
+ *
+ * This is a PHP implementation of Underscore's uniqueId method. A static variable
+ * contains an integer that is incremented with each call. This number is returned
+ * with the optional prefix. As such the returned value is not universally unique,
+ * but it is unique across the life of the PHP process.
+ *
+ * @since 4.9.9
+ *
+ * @staticvar int $id_counter
+ *
+ * @param string $prefix Prefix for the returned ID.
+ * @return string Unique ID.
+ */
+function wp_unique_id( $prefix = '' ) {
+	static $id_counter = 0;
+	return $prefix . (string) ++$id_counter;
+}
+
 /**
  * Get last changed date for the specified cache group.
  *
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 73f81ee976..cca8da6b74 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.0-alpha-43657';
+$wp_version = '5.0-alpha-43658';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.