avatar must be a string (was undefined) although undefined it expected type

I have the following type:

import { type } from "arktype";

export const profileData = type({
    firstName: 'string',
    lastName: 'string',
    'avatar?': 'string'
});
export type ProfileData = typeof profileData.infer

import { type } from "arktype";

export const profileData = type({
    firstName: 'string',
    lastName: 'string',
    'avatar?': 'string'
});
export type ProfileData = typeof profileData.infer

This is working:

const data = profileData.partial()({ firstName: 'John', lastName: 'Doe' });

const data = profileData.partial()({ firstName: 'John', lastName: 'Doe' });

But this throws an avatar must be a string (was undefined) error:

const data = profileData.partial()({
  firstName: 'John', 
  lastName: 'Doe',
  avatar: undefined
});

const data = profileData.partial()({
  firstName: 'John', 
  lastName: 'Doe',
  avatar: undefined
});

although it should be in the expected output range:

const data: ArkErrors | {
    firstName?: string | undefined;
    lastName?: string | undefined;
    avatar?: string | undefined;
}

const data: ArkErrors | {
    firstName?: string | undefined;
    lastName?: string | undefined;
    avatar?: string | undefined;
}

but still, it throws an avatar must be a string (was undefined) error 🤔

8 Replies

MichaOP•2w ago

Workaround: Adding the "undefined" keyword explicitly.

export const profileData = type({
    firstName: 'string',
    lastName: 'string',
    'avatar?': 'string | undefined'
});

export const profileData = type({
    firstName: 'string',
    lastName: 'string',
    'avatar?': 'string | undefined'
});

https://arktype.io/docs/primitives#undefined But this limits the usage of .partial(). So, if there would be a way that .partial() can do this automatically, this would be awesome.

ArkType Docs

Optimized runtime validation for TypeScript syntax

ssalbdivad•2w ago

Note this is also the behavior in TS with exactOptionalPropertyTypes:

ssalbdivad•2w ago

Also I realize now my naming is terrible and confusing but pretend string is key or something 😛

ssalbdivad•2w ago

You should keep an eye on this issue though as it seems like the behavior you want: https://github.com/arktypeio/arktype/issues/1191 (fixed link)

GitHub

Add an option to allow undefined for optional properties · Issue ...

Request a feature Add a global option to allow undefined as a value for optional properties. configure({ optionalAllowsUndefined: true }); 🤷 Motivation const arkUser = type({ phoneNumber: 'stri...

Jacob•7d ago

Ooo this should go on that “Zod users” migration page - Zod allows undefined in optional() (example)

Zod Playground

An interactive playground for testing and learning Zod schemas

ssalbdivad•7d ago

I wonder if that will still be the default in v4 - @colinhacks was just posting about the meaningful distinction https://x.com/colinhacks/status/1893974904984547373

Colin McDonnell (@colinhacks) on X

if I may be so bold, I'd like to propose some much-needed nomenclature

Jacob•7d ago

Interesting! I always did find it confusing how both no key and key set to undefined are treated the same in some code and not others (in general, not just within validation libs)

ssalbdivad•7d ago

Yeah, the reason EOPT is so important is without it, you have no way at all to represent what could be a meaningful distinction With it, you can express all variants of optionality, so a superset of what is possible without it

Gaming

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avatar must be a string (was undefined) although undefined it expected type

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