1 files changed, 2 insertions, 0 deletions
diff --git a/src/umd.js b/src/umd.js
index 90184d8..c7017ad 100644
--- a/src/umd.js
+++ b/src/umd.js
@@ -1,4 +1,6 @@
 (function(root, factory) {
+  'use strict'
+  /* istanbul ignore next */
   if (typeof define === 'function' && define.amd) {
     define(function(){
       return factory(root, root.document)