Check if object schema only includes partial keys of the input object

[hyunbinseo]

Continuing from hyunbinseo/svelte-kitty#26. Thank you @fabian-hiller for the ideas in that issue.

I would love a parse usage that checks if the object() schema is valid based on the input object type.

This is what I have been using, but it is too strict:

import { number, object, string, type GenericSchema } from 'valibot';

const parseTooStrict = <Schema extends GenericSchema<Input, unknown>, Input>(
  input: Input,
  schema: Schema,
) => {};

parseTooStrict(
  { a: '', b: 1 },
  // Property 'b' is missing in type '{ a: string; }'
  // but required in type '{ a: string; b: number; }'
  object({ a: string() }), //
);

The Partial<> version does not work, because it allows undefined key-values:

const parseTooLoose = <TInput, TSchema extends GenericSchema<Partial<TInput>, unknown>>(
  input: TInput,
  schema: TSchema,
) => {};

parseTooLoose(
  { a: '', b: 1 }, // Property 'c' does not exist
  object({ a: string(), c: number() }), // so this should error
);

[fabian-hiller]

I think I would move this to a discussion since it seems not to be an "issue" of Valibot and more a question. Or am I wrong?