Have readonly action return ReadonlyMap and ReadonlySet for Map and Set

[bjohn465]

Would it be possible for the readonly action to convert a Map to a ReadonlyMap? It currently produces a Readonly<Map>, which makes all the properties of the Map readonly, so I couldn't, for example, modify the clear method, but I could still call the clear method without receiving a TypeScript error.

Here's some example code (also available in the Valibot playground):

import * as v from 'valibot';

const Schema = v.pipe(
  v.array(
    v.object({ id: v.string(), data: v.string() })
  ),
  v.transform((input) => new Map(input.map((item) => [item.id, item]))),
  v.readonly()
);

const result = v.parse(Schema, [
  { id: 'a1', data: 'a-one' },
  { id: 'b2', data: 'b-two' },
]);

console.log(Array.from(result.entries()))

// This should cause a TypeScript error for a ReadonlyMap
result.clear();

console.log(Array.from(result.entries()))

A similar thing happens for a Set, so if it is possible for the readonly action to produce a ReadonlySet, that would be great, too.

If you do not want to change the behavior of the readonly action to produce ReadonlyMap and ReadonlySet for Map and Set instances, then how would you feel about a separate action that could do this?

[fabian-hiller]

Create idea! The next v1 RC version will support it! 🚀

[bjohn465]

🎉 Thank you!

For my future reference (and anyone else who comes across this discussion in the future), this appears to be the commit where support for this was added: 3e7879b

[fabian-hiller]

Valibot v1.0.0-rc.2 is available