diff --git a/src/class.StringBuilder.php b/src/class.StringBuilder.php
index 358525e..1a1eed8 100644
--- a/src/class.StringBuilder.php
+++ b/src/class.StringBuilder.php
@@ -51,6 +51,7 @@ class StringBuilder {
      * @return void 
      */
     public function __construct(bool $unique=false) {
+        $this->unique = $unique;
         $this->parts = [];
         $this->vars = [];
     }