Modify sourcemap in production

Author: dangvanthanh

dist/assets/js/app.js

@@ -42,7 +42,7 @@ const isProduction = process.env.NODE_ENV === `production`
 const isDevelopment = process.env.NODE_ENV === `development`
 
 if (isProduction) {
-  config.sourcemap = false
+  config.output.sourcemap = false
   config.plugins.push(
     replace({
       'process.env.NODE_ENV': JSON.stringify('production')