Strict type safety for schema's

[jayf0x]

Basic setup on how to have strict typing to make sure no mismatching values are ever passed to the schema:

import { Schema } from 'leva/dist/declarations/src/types';


type ControlFor<T> = {
  value: T;
  options: readonly T[];
};

type StrictSchema<C> = {
  [K in keyof C]: ControlFor<C[K]>;
};

type Config = {
  color: 'red' | 'blue' | 'green';
};

const my_schema: StrictSchema<Config> = {
  color: { value: 'blue', options: ['red'] },
};

const C = () => {
  const store = useCreateStore();

  const { color } = useControls('settings', my_schema, { store });

  return (
    <>
      <LevaPanel store={store} />
      <div style={{ background: color }}>test</div>
    </>
  );
};

---

This approach enforces a relationship between value and options, but it requires defining custom wrapper types (ControlFor, StrictSchema) instead of using the built-in Schema and is still far from perfect for all possible values.

It would be useful if the library exposed a stricter, generic-friendly schema type (or helper) that preserves the link between:

• the control value
• and its allowed options

Right now, Schema[keyof Schema] is too permissive, so mismatches like invalid options are not caught by TypeScript without additional user-defined types.