Joi.Forbidden() should prevent property from being output in typescript

When Forbidden and/or Strip is used, the resulting typescript model should not have the entry defined in its model.

export const examplePOSTBodySchema = baseSchema
  .fork(['id'], (x) => x.forbidden().strip(true))
  .meta({className: 'examplePOSTBody'});

Here I am forking a base schema and trying to remove the id parameter. Unfortunately Forbidden is not supported so id is still output in the resulting model.

[shennan]

I have a scenario where I use Joi.forbidden() to indicate that the value should be undefined.

So my expected behaviour would be:

const RequestBodySchema = Joi.forbidden()

RequestBodySchema.validate(undefined) // Passes
RequestBodySchema.validate({}) // Error
RequestBodySchema.validate({ foo: 'bar' }) // Error

With this in mind, I think Joi.forbidden() should actually compile to:

type RequestBodySchema = never

Any thoughts on this? Currently it just compiles to any, which I think is wrong.

[shennan]

This doesn’t work in latest version (not tested 4.0.0).

This:

const SomeForbiddenSchema = Joi.forbidden()

Produces this:

export type undefined = any;