Nodejs - Joi Check if string is in a given list

Question

I\'m using Joi package for server side Validation.
I want to check if a given string is in a given list or if it is not in a given list.(define black list or white list for

Answer 1

How about:

var schema = Joi.object().keys({
    firstname: Joi.string().valid(['a','b']),
    lastname : Joi.string().invalid(['c','d']),
});

There are also aliases: .allow and .only

and .disallow and .not