Improve monorepo support for no-extraneous-dependencies rule

[hulkish]

Solves #935

[coveralls]

Coverage increased (+0.01%) to 96.504% when pulling eac714f on hulkish:improve-monorepo-support-no-extraneous-dependencies-rule into 4e37dbf on benmosher:master.

[ljharb]

In general, I'm still not sure this is a useful feature. Deps shouldn't be resolved from outside of a subpackage in a lerna-style monorepo.

[ljharb]

let's use the has module for this.

[hulkish]

@ljharb It's a documented approach in the readme for lerna: https://github.com/lerna/lerna/blob/master/README.md#common-devdependencies

Furthermore, node itself inherently resolves dependencies from parent node_modules dirs.

When you have... let's say 10-30 packages you're managing in a monorepo - then sure, not a big deal to manage dev deps on a per package basis.

However, at my job for example we manage a monorepo with well over 100 packages.

In this scenario; the task of managing dev deps for this volume of packages quickly outgrows what's practical.

While I agree that this is up for debate on a best practices basis - I'm not sure how valueable it is to have this flexibility prevented at the level of an eslint plugin.

Personally, I've found that hoisting all of these dev deps to the root of monorepo brings a significant benefit and gained sanity.

[tizmagik]

Thank you for this PR @hulkish -- this has been a pain point for us so far. Hopefully this gets merged and released 🙏

[hulkish]

@ljharb hoping this can land.. is there anything I can improve to allow it?

[gotbahn]

Thanks for PR. We also reach this problem in monorepo. There even extra plugin in the wild https://github.com/Dreamscapes/eslint-import-resolver-lerna which partially solves it.
But have a solution in eslint-plugin-import is definitely better.

[dan-kez]

I've also run into this issue. I would love to see this merged.

[benmosher]

Why add a new top-level setting (import/paths) instead of expanding the existing packageDir rule option to be either a string or a list of strings?

[hulkish]

@benmosher hmm, sure - but, how would you configure packageDir in your .eslintrc?

[dan-kez]

@hulkish I believe the relevant PR is #685

[benmosher]

thanks for the PR reference @dmk255! other relevant reading:

• Change packageDir to packageDirs for no-extraneous-dependencies rule #1053
• no-extraneous-dependencies doesn't support nested package.json #458

[evocateur]

I just turn off import/no-extraneous-dependencies for any test files in the monorepo with an overrides key. import/no-unresolved already handles "is it installed somewhere", so extraneous-ness in test files seems beside the point. ${ROOT}/.eslintrc.yaml looks like this:

---
  extends: airbnb
  root: true
  overrides:
    - files: "**/*{-,.}{test,stories}.js"
      rules:
        # devDependencies are all in the root
        import/no-extraneous-dependencies: off

[hulkish]

Seems like this is just going to be an endless debate of correctness vs practicality.

I'll just fork and publish this as a different package.

[ljharb]

You’re welcome to do that, but this should stay open.

[hulkish]

@benmosher I actually had this work changed to use packageDir already. Just updated this pr with that code.

I don't care if we use my pr or yours, tbh. @ljharb Whichever you guys think is best.

[hulkish]

Just wondering... what's holding this up? What needs to be done to get this merged?

[benmosher]

busy week at work, but it's top of my queue for this project when I get time

[hulkish]

@benmosher thanks!

[benmosher]

@hulkish fyi, merged mine because I had fixed up and added a few more tests, LMK if I missed anything though