Feature Request: use node module resolution semantics for rulesDirectory

[donaldpipowitch]

extends uses node module resolution semantics to find files and you can specify relative paths to files, too. I'd need the same behaviour for rulesDirectory. E.g. I want to use tslint-react/rules which is sometimes in ./node_modules/tslint-react/rules and sometimes in ../node_modules/tslint-react/rules in my case. (I build a generic build tool configuration similar to create-react-app, so I don't always have full control about the projects where my configuration is used..)

[donaldpipowitch]

With this pull request we can now write something like:

{
  "rulesDirectory": [
    "tslint-eslint-rules/dist/rules"
  ]
}

Instead of

{
  "rulesDirectory": [
    "./node_modules/tslint-eslint-rules/dist/rules"
  ]
}

or

{
  "rulesDirectory": [
    "../node_modules/tslint-eslint-rules/dist/rules"
  ]
}

This is very useful for tools which offer a tslint.json and are installed as a dependency of other projects (like this one), because you never really know where your exact dependency will be installed (because sometimes you install your package normally, sometimes it is symlinked, and so on).

[adidahiya]

@donaldpipowitch makes sense, that is a good motivation for making this change

[adidahiya]

Your PR #2358 seems fine as an enhancement, but I just realized that custom rule packages really ought to configure rulesDirectory themselves so that users don't have to worry about specifying the directory -- instead, you just can just rely on "extends" composition semantics. tslint-react.json does this.

[donaldpipowitch]

You're right. This would work, too. But then I maybe need to overwrite the default settings.

[donaldpipowitch]

From buzinas/tslint-eslint-rules#214 (comment) I think the difference is this:

• extends: Allows me to use custom rules from other packages. I get all rules with default configs and can opt-out from rules. If new rules are added in a new version I get them automatically.
• rulesDirectory : Allows me to use custom rules from other packages. I opt-in to use certain rules with my specific configs. If new rules are added in a new version I don't get them automatically.