diff --git a/README.md b/README.md
index 3553fb4..c68a534 100644
--- a/README.md
+++ b/README.md
@@ -156,7 +156,7 @@ mode using `webpack -w`.
   ```
   {
     code?: string;
-    message?: string;
+    message?: string | RegExp;
     file?: string;
   }
   ```