diff --git a/build/api-gen/clean-name.js b/build/api-gen/clean-name.js
index 49f7cd4c..b8dc0989 100644
--- a/build/api-gen/clean-name.js
+++ b/build/api-gen/clean-name.js
@@ -1,5 +1,5 @@
-var re = /[\.-]/g
-var omitRe = /[\(\)]/g
+let re = /[\.-]/g
+let omitRe = /[\(\)]/g
 
 module.exports = function cleanName(raw) {
   return raw.replace(re, "-").replace(omitRe, "");