In extension of #938, I'm looking into adding support for the symbol type to Joi to allow something like this:

const enums = {
    first: Symbol('first'),
    second: Symbol('second')
};
const schema = Joi.symbol().map(enums);

schema.validate('first'); // value = Symbol(first)

This will enable eg. an options schema to declare enums using symbols instead of strings.

I could probably create it as an extension, but given that it is a native type (typeof Symbol() === 'symbol'), I'd say that it needs to be a part of the standard package.

How does this sound?