diff --git a/src/rollup/plugins/static.ts b/src/rollup/plugins/static.ts
index c2b138bedb..1e5079dfa7 100644
--- a/src/rollup/plugins/static.ts
+++ b/src/rollup/plugins/static.ts
@@ -49,7 +49,10 @@ export function dirnames (): Plugin {
   return {
     name: 'dirnames',
     renderChunk (code, chunk) {
-      return code + (chunk.isEntry ? 'global.mainDir="undefined"!=typeof __dirname?__dirname:require.main.filename;' : '')
+      return {
+        code: code + (chunk.isEntry ? 'global.mainDir="undefined"!=typeof __dirname?__dirname:require.main.filename;' : ''),
+        map: null
+      }
     }
   }
 }