diff --git a/README.md b/README.md
index 43444fa..1f1be6b 100644
--- a/README.md
+++ b/README.md
@@ -96,6 +96,7 @@ Options:
   --extensions, -x         Allows some extensions to be parsed as valid source.
                            First extension will always be preferred to homonyms
                            with another allowed extension.
+                                                       [array] [default: ["js"]]
   --outputFile, -o         Output file            [string] [default: "index.js"]                                                      [array] [default: ["js"]]
 
 Examples: