# RefArray.map

Map (Endomorphic) the values of a RefArray.

## Signatures

```ts
export declare const map: {
    <A>(f: (a: A, index: number) => A): <E, R>(ref: RefArray<A, E, R>) => RefSubject.Computed<ReadonlyArray<A>, E, R>;
    <A, E, R>(ref: RefArray<A, E, R>, f: (a: A, index: number) => A): RefSubject.Computed<ReadonlyArray<A>, E, R>;
};
```

## Why

The implementation applies the endomorphic map through `RefSubject.update`, replacing the
writable RefArray in one serialized transition. The published Computed return type does not
describe that runtime behavior.

## Ownership and lifetime

The Effect starts when run, participates in the source ref's serialized update boundary, and
acquires no resource. It returns the committed array and retains the ref's E and R channels.

## Known API defect

The public overloads currently declare `Computed<ReadonlyArray<A>, E, R>`, but the implementation
returns the update Effect from `RefSubject.update`. This documentation reports the shipped mismatch;
changing that signature or runtime behavior requires a separate compatibility decision.