diff --git a/packages/@vue/cli-service/lib/commands/build/setPublicPath.js b/packages/@vue/cli-service/lib/commands/build/setPublicPath.js
index 440563f88f..c83fbcad0d 100644
--- a/packages/@vue/cli-service/lib/commands/build/setPublicPath.js
+++ b/packages/@vue/cli-service/lib/commands/build/setPublicPath.js
@@ -1,7 +1,7 @@
 // This file is imported into lib/wc client bundles.
 
 if (typeof window !== 'undefined') {
-  let i
+  var i
   if ((i = window.document.currentScript) && (i = i.src.match(/(.+\/)[^/]+\.js$/))) {
     __webpack_public_path__ = i[1] // eslint-disable-line
   }