diff --git a/src/lib/stringify.es6 b/src/lib/stringify.es6
index 4f73ae8..bde4451 100644
--- a/src/lib/stringify.es6
+++ b/src/lib/stringify.es6
@@ -325,7 +325,7 @@ function transCode(code)
     return code;
 }
 
-let regFnHead = /function(.*?)\(\)/;
+let regFnHead = /function(.*?)\((.*?)\)/;
 
 function extractFnHead(fn)
 {