Function definePrimitive

Identity helper for declaring a primitive. Returns its argument unchanged.

The helper exists so TypeScript can infer TArgs from the annotation on build's parameter. Without it, the args shape must either be repeated as a variable type annotation, or TArgs falls back to its unknown default, discarding the args type at every downstream call site.

Does not validate the id namespace, that check happens at runtime inside register.

Returns

The same primitive, unchanged.

Example

The args shape lives only on build's parameter. TypeScript infers TArgs = OlderThanArgs and olderThan ends up typed as RulePrimitive<OlderThanArgs>, no extra annotation needed.

type OlderThanArgs = { days: number };

const olderThan = definePrimitive({
    id: 'limetech.older-than',
    reads: ['limeobject'],
    build: ({ days }: OlderThanArgs) => (scope) =>
        scope.get('limeobject') !== undefined && days > 0,
});