Split into modules and reorganize

src/tmpl/bin-wrapper-node-modules.sh.in

@@ -0,0 +1,2 @@
+#!/bin/sh
+exec node '@@SCRIPT_PATH@@' "$@"

src/tmpl/bin-wrapper-pnp.sh.in

@@ -0,0 +1,2 @@
+#!/bin/sh
+exec node -r '@@PNP_PATH@@' '@@SCRIPT_PATH@@' "$@"

src/tmpl/default.nix.in

@@ -0,0 +1,6 @@
+# This is a minimal `default.nix` by yarn-plugin-nixify. You can customize it
+# as needed, it will not be overwritten by the plugin.
+
+{ pkgs ? import <nixpkgs> { } }:
+
+pkgs.callPackage ./yarn-project.nix { } ./.

src/tmpl/yarn-project.nix.in

@@ -0,0 +1,96 @@
+# This file is generated by running "yarn install" inside your project.
+# Manual changes might be lost - proceed with caution!
+
+{ lib, coreutils, nodejs, stdenv }: src:
+
+let
+
+  yarnPath = @@YARN_PATH@@;
+  cacheFolder = @@CACHE_FOLDER@@;
+  cacheEntries = @@CACHE_ENTRIES@@;
+
+  # Fetch a single dependency.
+  fetchOne = let
+    builder = builtins.toFile "builder.sh" ''
+      source $stdenv/setup
+      cd "$src"
+      HOME="$TMP" yarn_cache_folder="$TMP" CI=1 \
+        node '${yarnPath}' nixify fetch-one $locatorHash
+      mv "$TMP/$outputFilename" $out
+    '';
+  in { name, filename, sha512, locatorHash }: stdenv.mkDerivation {
+    inherit name src builder locatorHash;
+    buildInputs = [ nodejs ];
+    outputFilename = filename;
+    outputHashMode = "flat";
+    outputHashAlgo = "sha512";
+    outputHash = sha512;
+  };
+
+  # Shell snippet to collect all project dependencies.
+  collectCache = lib.concatMapStrings (args: ''
+    cp ${fetchOne args} '${args.filename}'
+  '') cacheEntries;
+
+in stdenv.mkDerivation {
+  name = @@PROJECT_NAME@@;
+  inherit src;
+
+  # Tell node-gyp to use the provided Node.js headers for native code builds.
+  npm_config_nodedir = nodejs;
+  # Tell node-pre-gyp to never fetch binaries / always build from source.
+  npm_config_build_from_source = "true";
+
+  # Make sure the build uses the right Node.js version everywhere.
+  buildInputs = [ nodejs ];
+
+  # Defines the shell alias to run Yarn.
+  postHook = ''
+    yarn() {
+      CI=1 node "$NIX_YARN_PATH" "$@"
+    }
+  '';
+
+  configurePhase = ''
+    runHook preConfigure
+
+    # Copy over the Yarn cache.
+    # TODO: Can we do without the copy somehow? Links don't work.
+    rm -fr '${cacheFolder}'
+    mkdir -p '${cacheFolder}'
+    pushd '${cacheFolder}' > /dev/null
+    ${collectCache}
+    popd > /dev/null
+
+    # Store the absolute path to Yarn for the 'yarn' alias.
+    export NIX_YARN_PATH="$(readlink -f '${yarnPath}')"
+
+    # Run normal Yarn install to complete dependency installation.
+    yarn install --immutable --immutable-cache
+
+    runHook postConfigure
+  '';
+
+  buildPhase = ''
+    runHook preBuild
+    runHook postBuild
+  '';
+
+  installPhase = ''
+    runHook preInstall
+
+    mkdir -p $out/libexec $out/bin
+
+    # Move the entire project to the output directory.
+    mv $PWD "$out/libexec/$sourceRoot"
+    cd "$out/libexec/$sourceRoot"
+
+    # Update the path to Yarn.
+    export NIX_YARN_PATH="$(readlink -f '${yarnPath}')"
+
+    # Invoke a plugin internal command to setup binaries.
+    yarn nixify install-bin $out/bin
+
+    runHook postInstall
+  '';
+}