diff --git a/index.js b/index.js
index 6d5885a..ebbf011 100644
--- a/index.js
+++ b/index.js
@@ -119,7 +119,10 @@ function precinct(content, options = {}) {
 }
 
 function detectiveEs6Cjs(ast, detectiveOptions) {
-  return detectiveEs6(ast, detectiveOptions).concat(detectiveCjs(ast, detectiveOptions));
+  return [
+    ...detectiveEs6(ast, detectiveOptions),
+    ...detectiveCjs(ast, detectiveOptions)
+  ];
 }
 
 /**