diff --git a/pkgs/build-support/node/fetch-yarn-deps/default.nix b/pkgs/build-support/node/fetch-yarn-deps/default.nix
index e2724ab3a98b..4ef74c0cab88 100644
--- a/pkgs/build-support/node/fetch-yarn-deps/default.nix
+++ b/pkgs/build-support/node/fetch-yarn-deps/default.nix
@@ -25,7 +25,8 @@ in {
 
       tar --strip-components=1 -xf ${yarnpkg-lockfile-tar} package/index.js
       mv index.js $out/libexec/yarnpkg-lockfile.js
-      cp ${./.}/common.js ${./.}/index.js $out/libexec/
+      cp ${./common.js} $out/libexec/common.js
+      cp ${./index.js} $out/libexec/index.js
 
       patchShebangs $out/libexec
       makeWrapper $out/libexec/index.js $out/bin/prefetch-yarn-deps \
@@ -53,7 +54,8 @@ in {
 
       tar --strip-components=1 -xf ${yarnpkg-lockfile-tar} package/index.js
       mv index.js $out/libexec/yarnpkg-lockfile.js
-      cp ${./.}/common.js ${./.}/fixup.js $out/libexec/
+      cp ${./common.js} $out/libexec/common.js
+      cp ${./fixup.js} $out/libexec/fixup.js
 
       patchShebangs $out/libexec
       makeWrapper $out/libexec/fixup.js $out/bin/fixup-yarn-lock