Explicit readonly arrays

[estubmo]

I would like to be able to define explicit readonly arrays like in Zod: https://zod.dev/?id=readonly

import { record, string, object, url, nativeEnum, optional, array, Input } from "valibot";

const TAGS = {
  Blog: "Blog",
  NEWSPAPER: "Newspaper",
  TV: "TV",
} as const;

const NETWORK = {
  NETWORK1: "Network 1",
  NETWORK2: "Network 2",
} as const;


const SourceSchema = record(
  string(),
  object({
    name: string(),
    url: string([url()]),
    network: nativeEnum(NETWORK),
    tags: optional(array(nativeEnum(TAGS))),
  }),
);

type Source = Input<typeof SourceSchema>;

export const SOURCE = {
  SITE1: {
    name: "Site 1",
    url: "https://www.site1.com",
    network: NETWORK.NETWORK1,
    tags: [TAGS.NEWSPAPER],
  },
  SITE2: {
    name: "Site 2",
    url: "https://www.site2.com",
    network: NETWORK.NETWORK1,
    tags: [TAGS.NEWSPAPER],
  },
  SITE3: {
    name: "Site 3",
    url: "https://www.site3.com",
    network: NETWORK.NETWORK2,
    tags: [TAGS.NEWSPAPER],
  },
  SITE4: {
    name: "Site 4",
    url: "https://www.site4.com",
    network: NETWORK.NETWORK2,
    tags: [TAGS.NEWSPAPER],
  },
} as const satisfies Source;

This gives error:

The type 'readonly ["Newspaper"]' is 'readonly' and cannot be assigned to the mutable type '("Blog" | "Newspaper" | "TV")[]'.

However, it does not if I remove satisifes Source, which I would like to keep for type safety.

Minimal repo:
https://stackblitz.com/edit/typescript-4synpa?file=schemas%2Fschemas.ts

[fabian-hiller]

Good idea. We should add a method for this. Are you interested in creating a PR?

[estubmo]

I'm sorry, but I'm not confident I'd be able to do it correctly.

[fabian-hiller]

No problem. I will try to do it in 1 to 2 weeks.