Add a key validator with Joi objects

[pierreis]

Currently, Joi only allows validating the unknown keys of an object using a regexp. While a good solution, it does adapt to more complex use-cases that would be better served by a Joi object.

For example, for email or uuid-like keys, I need to put a regex. This is sad as native validation already exists in Joi for these use-cases.

I would propose accepting as first argument a Joi string validator, while keeping the current behavior for compatibility.

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The result would be: Joi.object().pattern(Joi.string().email(), Joi.any())

[Marsup]

I've been thinking about doing this for a long while now. While less efficient than a regexp, it would be more legible.

Although I would say it doesn't necessarily need to be a string, like in many other cases in joi, anything that validates without error could be considered a match.

Care to do a PR ?

[pierreis]

I completely agree with that. I’ll check for a PR!

[DavidTPate]

Although I would say it doesn't necessarily need to be a string

Yeah, within an object you could have a key that is a number for example, there's also the question of things like Map and Set with how the key could be something like an object or array instead of just a primitive.

[Marsup]

This is already a 1st step, we'll deal with new ES6 types in another time, I'm not even sure it should inherit or be part of object.