diff --git a/pkgs/development/tools/misc/ctags/wrapped.nix b/pkgs/development/tools/misc/ctags/wrapped.nix
index ff959d94141..07a4b01ad19 100644
--- a/pkgs/development/tools/misc/ctags/wrapped.nix
+++ b/pkgs/development/tools/misc/ctags/wrapped.nix
@@ -56,8 +56,9 @@
   # var foo = function () { ... }
   # {
   # a : function () {}
+  # only recognize names up 100 characters. Else you'll be in trouble scanning compressed .js files.
   jsLang = [
-    "--regex-JavaScript=/([^ \\t]*)[ \\t]*:[ \\t]*function[ \\t]*\\(/\\1/f/"
+    "--regex-JavaScript=/([^ \\t]{1,100})[ \\t]*:[ \\t]*function[ \\t]*\\(/\\1/f/"
   ];
 
   # find foo in "foo =", don't think we can do a lot better