diff --git a/default.nix b/default.nix
index 54ece9a..22a1495 100644
--- a/default.nix
+++ b/default.nix
@@ -11,6 +11,7 @@ let
     # nix tools
     dhallToNix = import ./pkgs/dhallToNix.nix;
     dockerImage = callPackage ./pkgs/dockerImage.nix { };
+    srcNoTarget = import ./pkgs/srcNoTarget.nix;
 
     # other
     MoonPlus = callPackage ./pkgs/moonplus { };
diff --git a/pkgs/srcNoTarget.nix b/pkgs/srcNoTarget.nix
new file mode 100644
index 0000000..7c9aaa2
--- /dev/null
+++ b/pkgs/srcNoTarget.nix
@@ -0,0 +1,4 @@
+dir:
+builtins.filterSource
+  (path: type: type != "directory" || builtins.baseNameOf path != "target")
+  dir