Allow the CACHE_DIR environment variable to override the cache location

[Richienb]

When the environmental variable CACHE_DIR is specified, the specified directory will be used instead. This is useful in development situations where packages write useful information to the cache.

Closes #16

[Richienb]

@sindresorhus

[sindresorhus]

Did you see my comment: #10 (comment) ?

[sindresorhus]

This is useful in development situations where packages write useful information to the cache.

Can you be more specific about the use-case?

[Richienb]

@langri-sha Can you reference the packages you were talking about in #16 (comment)?

[langri-sha]

In my project I have 8 dependencies that use find-cache-dir. Of them two are completely unconfigurable: ava and @storybook/core.

To save ~30s per build (~23$/mo), I have a local find-cache-dir package and use Yarn's resolutions.

Feel free to use this if the PR doesn't get merged.

// package.json

{
  "resolutions": {
    "find-cache-dir": "file:your-workspace/find-cache-dir"
  }
}

// your-workspace/find-cache-dir/src/index.js

const findUp = require('find-up')
const path = require('path')
const { ensureDirSync } = require('fs-extra')

const root = findUp.sync('yarn.lock')

module.exports = (options = {}) => {
  const { name, create, thunk } = options
  
  const ensureDir = create ? ensureDirSync : path => path

  if (thunk) {
    return (...args) => ensureDir(path.join(root, '.cache', name, ...args))
  }

  return ensureDir(path.join('root', '.cache', name))
}

[Richienb]

@sindresorhus ^^

[langri-sha]

I wish to correct myself on the point of ava as I was looking closely in the sources. It expresses the same behavior of find-cache-dir, but doesn't actually use it.

[sindresorhus]

CACHE_DIR is a very generic environment variable, which is fine, but I think we should not put the cache directly in CACHE_DIR, but rather inside $CACHE_DIR/find-cache-dir, to prevent possible conflicts with other projects using that directory.

[Richienb]

@sindresorhus Ready for re-review!

[sindresorhus]

The code looks technically correct, but I feel like it could be refactored a bit to improve readability.

https://github.com/Richienb/find-cache-dir/blob/ea4a195f23faee1f150e7342dd136aefdb603c54/index.js#L20 is kinda awkward, if true, the directory is the actual cache directory, if false, it's the CWD directory.

This could be made a separate method: https://github.com/Richienb/find-cache-dir/blob/ea4a195f23faee1f150e7342dd136aefdb603c54/index.js#L32-L40 which could also include this part: https://github.com/avajs/find-cache-dir/blob/8ec64dcb35b3975e13a08dba2a3b6e7fb599ae30/index.js#L19-L25

That way the main method logic only handles the resolved cache directories.

[sindresorhus]

I think it could still be made more readable. And this is not resolved:

https://github.com/Richienb/find-cache-dir/blob/ea4a195f23faee1f150e7342dd136aefdb603c54/index.js#L20 is kinda awkward, if true, the directory is the actual cache directory, if false, it's the CWD directory.

[Richienb]

@sindresorhus I found a refactoring strategy to make the code more readable.

[sindresorhus]

Looks good :)