diff --git a/default.nix b/default.nix
index de9a7d7..0697f7b 100644
--- a/default.nix
+++ b/default.nix
@@ -7,16 +7,17 @@
 , optipng
 , pngquant
 , libwebp
-, ...
-}:
-let
-  pnpm2nix = pkgs.callPackage (
+
+, pnpm2nix ? pkgs.callPackage (
     builtins.fetchGit {
       url = "https://github.com/nix-community/pnpm2nix.git";
       rev = "f67be0925a91b92f54d99dbdead7a06920b979ac";
     }
-  ) {};
+  ) {}
 
+, ...
+}:
+let
   nodeCleanSourceFilter = name: type:
     pkgs.lib.cleanSourceFilter name type
     && ((baseNameOf name) != "node_modules");