Add an option to allow undefined for optional properties

[JesusTheHun]

Request a feature

Add a global option to allow undefined as a value for optional properties.

configure({ optionalAllowsUndefined: true });

🤷 Motivation

const arkUser = type({ phoneNumber: 'string?' });

The type above produces the type { phoneNumber?: string } and will not validate { phoneNumber: undefined } at runtime.

💡 Solution

Another solution could be a new-ish syntax like string??.

[Asfamilybank]

Are there any updates?🧐

[ssalbdivad]

I would accept external contributions on this. Otherwise it would likely be sometime after stable 2.0.

[LukeAbby]

Out of merely interest is there actually any way to get exactly this proposed API to work?

configure({ optionalAllowsUndefined: true });

Traditionally I've had to have something like this:

configure({ optionalAllowsUndefined: true });

declare module "arktype/configuration" {
    interface Config {
        optionalAllowsUndefined: true
    }
}

[ssalbdivad]

ArkType uses a global called ArkEnv for type-level configuration, e.g.:

This is something I'm working on documenting more now.

However, this wouldn't be a type-level config. You would just change this setting to match the exactOptionalPropertyTypes option in your tsconfig. Only the runtime behavior would need to be configured from within ArkType