`type` can be an array

[not-my-profile]

See https://datatracker.ietf.org/doc/html/draft-bhutton-json-schema-01#name-assertions-and-instance-pri.

E.g. the following is a valid OpenAPI 3.1 schema object:

{
    "type": ["string", "null"],
    "maxLength": 255
}

[omermecitoglu]

Yes, you are correct but unfortunately #3 is not the solution. It will break the Discriminated Unions.

[not-my-profile]

I'm afraid I don't quite follow, can you please give me an example? Type narrowing with e.g. obj.type == "string" still works. Yes you won't be able to narrow down the type if type is an array but this also didn't work before so #3 is not breaking it. And I don't think the type narrowing is that helpful since all the properties are optional anyway (except items in ArraySchema but I think according to the spec that should also be optional).

[not-my-profile]

I think if you still want to use the type narrowing the best you can do is use a function like the following:

function * iterSchemaObject(obj: SchemaObject) {
  if (typeof obj.type === "object") {
    for (const type of obj.type) {
      yield { ...obj, type };
    }
  } else {
    yield obj
  }
}

[omermecitoglu]

Ok thanks for your research. I'll consider it.

[not-my-profile]

I've refactored #3 so that we no longer need to manually list each type in the UnionSchema :)