enhancement: add config validation

[cosmiconfig]

enhancement: add config validation

[davidtheclark]

I imagine this as a separate project. I think it makes sense to keep cosmiconfig strictly focused on loading and parsing. What you do with the parsed config is not cosmiconfig's concern.

It would definitely be cool to have another library shared by open source projects that validates the parsed config, so each project doesn't have to implement that on its own! It might be pretty hard, though, to make something generic that will meet the different validation needs of different projects. Fun problem.

[sudo-suhas]

Hey @aladdin-add, could you elaborate your use-case? What would be the advantage of adding this functionality to cosmiconfig instead of letting the client implement it themselves? If the client were to implement it, they would have the freedom to choose the validation library of their choice. Another option would be to implement a external wrapper module which would use the transform hook to perform the validation.

[aladdin-add]

thanks for the quick response!

I'm considering using cosmiconfig in eslint (eslint/eslint#9637). config validation is so common, so I think providing an optional implement but can be customized can be handy for users, and no harm to flexibility. you recon?

[sudo-suhas]

@davidtheclark, @azz, @okonet Do you mind sharing your opinion on this?

[azz]

There's already at least two really good libs for this that I'm aware of:

• jest-validate
• joi

[sudo-suhas]

Based on feedback, we won't be developing this feature in cosmiconfig. Closing the issue for now.