Respect NODE_PATH environment variable

[TLATER]

🐛 bug report

When trying to build with no node_modules directory, but all my dependencies in a directory listed in NODE_PATH, parcel will fail to run because it cannot resolve its plugins.

I believe this will also extend to bundling modules from the path, since the module resolution is custom and I can't find any references to NODE_PATH in the relevant source files.

🎛 Configuration (.babelrc, package.json, cli command)

This can be reproduced with no configuration at all! See the code sample section.

🤔 Expected Behavior

Parcel should resolve modules correctly according to NODE_PATH, and in the test case output an empty file (I think, I'll admit I'm too lazy to check what parcel outputs for an empty html file right now).

😯 Current Behavior

Parcel complains that even its built-in plugins are missing.

The exact error is:

@parcel/core: Cannot find extended parcel config
/home/tlater/Documents/Projects/tlaternet-templates/.parcelrc:2:15
  1 | {
> 2 |   "extends": ["@parcel/config-default"],
>   |               ^^^^^^^^^^^^^^^^^^^^^^^^ Cannot find module "@parcel/config-default"
  3 |   "transformers": {
  4 |     "*.mp3": [ "@parcel/transformer-raw" ]

💁 Possible Solution

Fix the module resolution to respect NODE_PATH.

🔦 Context

I'm trying to deploy a website on a NixOS host. I'm using node2nix to achieve this, which uses the NODE_PATH variable to allow the package manager to take control of the node_modules.

💻 Code Sample

Easiest reproduction scenario:

1. mkdir test && pushd test
2. npm install parcel
   • Make sure you don't have a directory with a node_modules or package*.json in it as any parent directory up to the root.
3. export NODE_PATH="$(pwd)/node_modules"
4. popd
5. touch empty.html
6. "$NODE_PATH/.bin/parcel" empty.html

🌍 Your Environment

Software	Version(s)
Parcel	2.0.0-beta.2
Node	v12.21.0
npm/Yarn	npm 6.14.11
Operating System	NixOS 20.09.20210401.da7f4c4 (Nightingale)

[mischnic]

NODE_PATH would have to be taken into account in these files:

• https://github.com/parcel-bundler/parcel/blob/v2/packages/core/package-manager/src/NodeResolver.js (for plugin/config loading)
• https://github.com/parcel-bundler/parcel/blob/v2/packages/utils/node-resolver-core/src/NodeResolver.js (for actually resolving imports)

[josephshen]

Hi @TLATER check this pull #8273 (comment)

[TLATER]

Very cool. Surprisingly tidy and simple, I should have looked at this more closely years ago, been using an ugly hack ever since :)

[toastal]

This would be useful for using npmlock2nix when developing Nix as you can’t run network requests from a Nix derivation.

[ggPeti]

@devongovett please support this, some of us like to avoid littering source directories with artifacts like node_modules. they make development environments stateful and unpredictable.