Feature: Allow Arborist to configure node_modules and manifest locations independently

Is there an existing issue for this?

• I have searched the existing issues

This issue exists in the latest npm version

• I am using the latest npm

Current Behavior

This is not a bug report, but I didn't see a way to do a feature request.

For Arborist to generate a tree based on node_modules and a manifest, it currently expects them both in the same location and outputs its lockfile there. This is problematic for isolate-package, which wants to generate a pruned lockfile based on the node_modules from the monorepo root, plus an adapted manifest living in a different (isolate) directory.

To make things work, I need to temporarily move the node_modules folder into the isolate directory before running Arborist, and then move it back when finished.

Apart from it being an ugly hack, it prevents multiple processes from executing in parallel. This is a problem because in a monorepo it's likely you want to isolate and deploy multiple packages in parallel.

Generating pruned lockfiles for Yarn and PNPM is not so problematic, but for NPM this is currently the only way to do it AFAIK.

Here is a link to the code with the workaround:
https://github.com/0x80/isolate-package/blob/main/src/lib/lockfile/helpers/generate-npm-lockfile.ts

Expected Behavior

Make Arborist accept a separate configuration for locations of the node_modules and manifest files. Please? 🙏

Steps To Reproduce

No response

Environment

No response

Start by reading the workaround in src/lib/lockfile/helpers/generate-npm-lockfile.ts from isolate-package and compare it with Arborist's current location assumptions. Done means Arborist can configure node_modules and manifest locations independently, generate the pruned lockfile in the intended location, and avoid moving directories so multiple isolation processes can run in parallel.