diff --git a/pkgs/build-support/node/fetch-yarn-deps/default.nix b/pkgs/build-support/node/fetch-yarn-deps/default.nix
index 4ef74c0cab88..433dc17a75e3 100644
--- a/pkgs/build-support/node/fetch-yarn-deps/default.nix
+++ b/pkgs/build-support/node/fetch-yarn-deps/default.nix
@@ -1,4 +1,16 @@
-{ stdenv, lib, makeWrapper, coreutils, nix-prefetch-git, fetchurl, nodejs-slim, prefetch-yarn-deps, cacert, callPackage, nix }:
+{
+  stdenv,
+  lib,
+  makeWrapper,
+  coreutils,
+  nix-prefetch-git,
+  fetchurl,
+  nodejs-slim,
+  prefetch-yarn-deps,
+  cacert,
+  callPackage,
+  nix,
+}:
 
 let
   yarnpkg-lockfile-tar = fetchurl {
@@ -6,9 +18,9 @@ let
     hash = "sha512-GpSwvyXOcOOlV70vbnzjj4fW5xW/FdUF6nQEt1ENy7m4ZCczi1+/buVUPAqmGfqznsORNFzUMjctTIp8a9tuCQ==";
   };
 
-  tests = callPackage ./tests {};
-
-in {
+  tests = callPackage ./tests { };
+in
+{
   prefetch-yarn-deps = stdenv.mkDerivation {
     name = "prefetch-yarn-deps";
 
@@ -30,12 +42,20 @@ in {
 
       patchShebangs $out/libexec
       makeWrapper $out/libexec/index.js $out/bin/prefetch-yarn-deps \
-        --prefix PATH : ${lib.makeBinPath [ coreutils nix-prefetch-git nix ]}
+        --prefix PATH : ${
+          lib.makeBinPath [
+            coreutils
+            nix-prefetch-git
+            nix
+          ]
+        }
 
       runHook postInstall
     '';
 
-    passthru = { inherit tests; };
+    passthru = {
+      inherit tests;
+    };
   };
 
   fixup-yarn-lock = stdenv.mkDerivation {
@@ -63,45 +83,75 @@ in {
       runHook postInstall
     '';
 
-    passthru = { inherit tests; };
+    passthru = {
+      inherit tests;
+    };
   };
 
-  fetchYarnDeps = let
-    f = {
-      name ? "offline",
-      src ? null,
-      hash ? "",
-      sha256 ? "",
-      ...
-    }@args: let
-      hash_ =
-        if hash != "" then { outputHashAlgo = null; outputHash = hash; }
-        else if sha256 != "" then { outputHashAlgo = "sha256"; outputHash = sha256; }
-        else { outputHashAlgo = "sha256"; outputHash = lib.fakeSha256; };
-    in stdenv.mkDerivation ({
-      inherit name;
+  fetchYarnDeps =
+    let
+      f =
+        {
+          name ? "offline",
+          src ? null,
+          hash ? "",
+          sha256 ? "",
+          ...
+        }@args:
+        let
+          hash_ =
+            if hash != "" then
+              {
+                outputHashAlgo = null;
+                outputHash = hash;
+              }
+            else if sha256 != "" then
+              {
+                outputHashAlgo = "sha256";
+                outputHash = sha256;
+              }
+            else
+              {
+                outputHashAlgo = "sha256";
+                outputHash = lib.fakeSha256;
+              };
+        in
+        stdenv.mkDerivation (
+          {
+            inherit name;
 
-      dontUnpack = src == null;
-      dontInstall = true;
+            dontUnpack = src == null;
+            dontInstall = true;
 
-      nativeBuildInputs = [ prefetch-yarn-deps cacert ];
-      GIT_SSL_CAINFO = "${cacert}/etc/ssl/certs/ca-bundle.crt";
-      NODE_EXTRA_CA_CERTS = "${cacert}/etc/ssl/certs/ca-bundle.crt";
+            nativeBuildInputs = [
+              prefetch-yarn-deps
+              cacert
+            ];
+            GIT_SSL_CAINFO = "${cacert}/etc/ssl/certs/ca-bundle.crt";
+            NODE_EXTRA_CA_CERTS = "${cacert}/etc/ssl/certs/ca-bundle.crt";
 
-      buildPhase = ''
-        runHook preBuild
+            buildPhase = ''
+              runHook preBuild
 
-        yarnLock=''${yarnLock:=$PWD/yarn.lock}
-        mkdir -p $out
-        (cd $out; prefetch-yarn-deps --verbose --builder $yarnLock)
+              yarnLock=''${yarnLock:=$PWD/yarn.lock}
+              mkdir -p $out
+              (cd $out; prefetch-yarn-deps --verbose --builder $yarnLock)
 
-        runHook postBuild
-      '';
+              runHook postBuild
+            '';
 
-      outputHashMode = "recursive";
-    } // hash_ // (removeAttrs args (["name" "hash" "sha256"] ++ (lib.optional (src == null) "src"))));
-
-  in lib.setFunctionArgs f (lib.functionArgs f) // {
-    inherit tests;
-  };
+            outputHashMode = "recursive";
+          }
+          // hash_
+          // (removeAttrs args (
+            [
+              "name"
+              "hash"
+              "sha256"
+            ]
+            ++ (lib.optional (src == null) "src")
+          ))
+        );
+    in
+    lib.setFunctionArgs f (lib.functionArgs f) // { inherit tests; };
 }