CODE EXAMPLE FOR JAVASCRIPT

Joi validation "Joi.when()"

Joi.object().keys({
    contact: Joi.object().keys({
        first_name: Joi.string(),
        last_name: Joi.string(),
        phone: Joi.string(),
    }),
    address: Joi.object().keys({
        place: Joi.string(),
        city: Joi.string().min(2).max(30),
        street: Joi.string(),
        house_number: Joi.string()
    }).when('contact', {
        is: Joi.object().keys({
            first_name: Joi.exist(),
            last_name: Joi.exist(),
            phone: Joi.exist(),
        }),
        then: Joi.object({ place: Joi.required() }).required(),
        otherwise: Joi.object({ place: Joi.forbidden() })
    }),
    passengers_amount: Joi.number(),
    notes: Joi.string()
});