diff --git a/core/project/lib/make-file-finder.js b/core/project/lib/make-file-finder.js
index 15a5b01b31..79360b1d2a 100644
--- a/core/project/lib/make-file-finder.js
+++ b/core/project/lib/make-file-finder.js
@@ -58,10 +58,6 @@ function makeFileFinder(rootPath, packageConfigs) {
     );
 
     // always flatten the results
-    return promise.then(flattenResults);
+    return promise.then(results => results.reduce((acc, result) => acc.concat(result), []));
   };
 }
-
-function flattenResults(results) {
-  return results.reduce((acc, result) => acc.concat(result), []);
-}