diff --git a/.eslintrc.js b/.eslintrc.js
index e7b76d3..43d3f38 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -8,6 +8,7 @@ module.exports = {
     ecmaVersion: 2017
   },
   rules: {
+    "no-undef": "error",
     "no-unused-vars": "warn"
   }
 };