Support 'packagejson' as a custom cwd option.

[cpsubrian]

Some context:

• I'm building an app as a mono-repo with lerna.
• I'd like to manage all the .babelrc config at the root level of the repo (not per sub-package).
• I'd like to be able to do import/requires like: import db from 'src/db', where 'src' is relative to the root of the package of the file being transpiled.

This PR facilitates that and is working great for me so far.

Sample .babelrc configuration:

{
  "plugins": [
    ["babel-plugin-module-resolver", {
      "root": ["./"],
      "cwd": "packagejson"
    }]
  ]
}

The key is that this approach works not matter what your actual 'cwd' is. This means that my imports work whether I am running babel-node/babel-watch from the repo root, or running babel on each sub-package individually.

I'm not married to find-root, it was literally the first 'find my package.json' module that I found 😄

[fatfisz]

@cpsubrian Hey, thanks for your contribution and sorry for taking that long!

Two small things:

• could you use pkg-up instead? It's also used in the "sibling" plugin eslint-import-resolver-babel-module, so the dependency would be shared.
• could you change the two ifs into a switch? This way the second condition won't depend on the first one in all cases.

[cpsubrian]

@fatfisz Thanks for the review. Will look into those changes and update.

[fatfisz]

@cpsubrian Hi, could you also rebase this on the beta branch?

The file where you should put the changes now is src/normalizeOptions.js, and the method is called normalizeCwd.

[cpsubrian]

@fatfisz Yep, no problem. Will do when I get a moment. Had to jump over to a different project last week.

[codecov]

Codecov Report

Merging #149 into beta will not change coverage.
The diff coverage is 100%.

Impacted Files	Coverage Δ
src/index.js	100% <ø> (ø)	⬆️
src/normalizeOptions.js	100% <100%> (ø)	⬆️

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[cpsubrian]

@fatfisz Rebased to beta and made those changes. I went with an else if instead of switch because the additional syntax noise not worth it unless we get to 3+ options (IMO). Technically, if we are going for micro-optimization and we expect most people to not use opts.cwd, then we should bail out on that case first (but then there will be some redundant logic in the function).

[fatfisz]

@cpsubrian That's ok, else if also works :) Will merge this later today.

[fatfisz]

Ooops, I've only now noticed a small problem in the tests - in two cases you are using describe instead of it. I'll just fix that before merging.

[cpsubrian]

@fatfisz Oh haha, I had fixed those locally but I guess I didn't push them. Oops!