diff --git a/packages/core/src/compress.js b/packages/core/src/compress.js
index 51a62e867..18cc10e9d 100644
--- a/packages/core/src/compress.js
+++ b/packages/core/src/compress.js
@@ -65,7 +65,7 @@ const createDirectory = file => {
   if (Array.isArray(file)) {
     file = file[0];
   }
-  const dir = file.substr(0, file.lastIndexOf('/'));
+  const dir = file && file.substr(0, file.lastIndexOf('/'));
   if (!dir) {
     return;
   }