arktype•14mo ago

How to declare an optional schema?

I wonder if it's possible to define a schema that is ok if data is undefined. E.g. in:

declare function foo(a?: string)v void

declare function foo(a?: string)v void

how to declare a schema for a?

18 Replies

ssalbdivad•14mo ago

Just create a union with undefined type("string|undefined")

OnkelTemOP•14mo ago

ok, I've prepared a specific example

OnkelTemOP•14mo ago

https://www.typescriptlang.org/play?#code/JYWwDg9gTgLgBAbzjAnmApnAvnAZlCEOAcgEMoBrVDYgbgCh6B6JuAeTBmAgDsBnegGNefeBE7d+AEjgBeZGnQAKBPThwANqR4BzAFwlRUYLuIAaNcnQAPGAeJGTO8-SwBKBs1YBhXrmA6QiLwwjz+OjLy1Mqq6jAQFOg89o6mFuoscAASEADuyBBwIKSJyAAWwHxwAArkXKQaAPyW4lwiBq2SfFIW7p6CWnxVACowVbFwAMTxiclwqTqeGazDFVWVNXXADQA8HG38AHyWk6HhBrWw2xo70RC4cJ0iUgB0JrjoUIdLcKFGAK6CeJQJRnAIGO4PMERN5hT5uRCWOJrF7TBJJOS-PwBF4zJIMdTIyqo6GY6EvJ78AnYVz0IA

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OnkelTemOP•14mo ago

import { type } from 'arktype';

// Options
const options$ = type({
  lang: 'string',
  text: 'string',
});

// Config
const config$ = type({
  token: 'string',
  // How to make this Partial?
  options: options$,
});

class Tts {
  #token: string;

  // This is Partial<Options>
  #config: Partial<typeof options$.infer>;

  constructor(config: typeof config$.infer) {
    this.#token = config.token;
    this.#config = config.options;
  }
}

import { type } from 'arktype';

// Options
const options$ = type({
  lang: 'string',
  text: 'string',
});

// Config
const config$ = type({
  token: 'string',
  // How to make this Partial?
  options: options$,
});

class Tts {
  #token: string;

  // This is Partial<Options>
  #config: Partial<typeof options$.infer>;

  constructor(config: typeof config$.infer) {
    this.#token = config.token;
    this.#config = config.options;
  }
}

OnkelTemOP•14mo ago

How can I make this partial?

ssalbdivad•14mo ago

Sounds like something @Dimava might have built at some point. The most straightforward solution would be to write a generic function that takes a type, Object.fromEntries(Object.entries(...).map(...)) its definition so that each key gets ? appended, then return it inferred like you did Partial will be builtin as a generic in beta, but I wanted to hold off adding APIs for that stuff until generics were available since I knew that would eventually be how they worked

OnkelTemOP•14mo ago

Also, I wonder if I reuse type correctly? Shouldn't I instead use scope?

ssalbdivad•14mo ago

What you did is good. Scopes are also good, a lot of it is preference. I would say if you aren't writing complex/cyclic expressions, just using types is usually enough

OnkelTemOP•14mo ago

Yeah So how to achieve this Partial thing now? A workaround would be... ?

ssalbdivad•14mo ago

I wrote it!

The most straightforward solution would be to write a generic function that takes a type, Object.fromEntries(Object.entries(...).map(...)) its definition so that each key gets ? appended, then return it inferred like you did

OnkelTemOP•14mo ago

Erm...

ssalbdivad•14mo ago

FINE

OnkelTemOP•14mo ago

I don't get it sorry

ssalbdivad•14mo ago

Something like this:

const partial = <t extends object>(base: Type<t>) =>
    type(
        Object.fromEntries(
            Object.entries(base.definition as object).map(([k, v]) => [`${k}?`, v])
        ) as Infer<Partial<t>>
    )

const partial = <t extends object>(base: Type<t>) =>
    type(
        Object.fromEntries(
            Object.entries(base.definition as object).map(([k, v]) => [`${k}?`, v])
        ) as Infer<Partial<t>>
    )

OnkelTemOP•14mo ago

I think I start getting the principle of making these hacks

ssalbdivad•14mo ago

Hopefully you'll have it totally down right before beta then you won't need it anymore :p

OnkelTemOP•14mo ago

then partial will be a built-in utility, right? 1274 commits ahead now... my gosh

ssalbdivad•14mo ago

Right You can use it like Partial<user> in a string or you'll be able to do partial(user) and pass a type in

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How to declare an optional schema?