1 files changed, 52 insertions, 0 deletions
diff --git a/nixpkgs/pkgs/build-support/node/import-npm-lock/hooks/canonicalize-symlinks.js b/nixpkgs/pkgs/build-support/node/import-npm-lock/hooks/canonicalize-symlinks.js
new file mode 100644
index 000000000000..81cd2593c5b2
--- /dev/null
+++ b/nixpkgs/pkgs/build-support/node/import-npm-lock/hooks/canonicalize-symlinks.js
@@ -0,0 +1,52 @@
+#!/usr/bin/env node
+const fs = require("fs");
+const path = require("path");
+
+// When installing files rewritten to the Nix store with npm
+// npm writes the symlinks relative to the build directory.
+//
+// This makes relocating node_modules tricky when refering to the store.
+// This script walks node_modules and canonicalizes symlinks.
+
+async function canonicalize(storePrefix, root) {
+  console.log(storePrefix, root)
+  const entries = await fs.promises.readdir(root);
+  const paths = entries.map((entry) => path.join(root, entry));
+
+  const stats = await Promise.all(
+    paths.map(async (path) => {
+      return {
+        path: path,
+        stat: await fs.promises.lstat(path),
+      };
+    })
+  );
+
+  const symlinks = stats.filter((stat) => stat.stat.isSymbolicLink());
+  const dirs = stats.filter((stat) => stat.stat.isDirectory());
+
+  // Canonicalize symlinks to their real path
+  await Promise.all(
+    symlinks.map(async (stat) => {
+      const target = await fs.promises.realpath(stat.path);
+      if (target.startsWith(storePrefix)) {
+        await fs.promises.unlink(stat.path);
+        await fs.promises.symlink(target, stat.path);
+      }
+    })
+  );
+
+  // Recurse into directories
+  await Promise.all(dirs.map((dir) => canonicalize(storePrefix, dir.path)));
+}
+
+async function main() {
+  const args = process.argv.slice(2);
+  const storePrefix = args[0];
+
+  if (fs.existsSync("node_modules")) {
+    await canonicalize(storePrefix, "node_modules");
+  }
+}
+
+main();