diff --git a/src/splitInteger.js b/src/splitInteger.js
index dd5009ff..d3da7485 100644
--- a/src/splitInteger.js
+++ b/src/splitInteger.js
@@ -1,3 +1,5 @@
+'use strict';
+
 /**
  * @param {number} value
  * @param {number} numberOfParts