# RefChunk.mapValues

Map the values of a RefChunk to a different type.

## Signatures

```ts
export declare const mapValues: {
    <A, B>(f: (a: A, index: number) => B): <E, R>(ref: RefChunk<A, E, R>) => RefSubject.Computed<Chunk.Chunk<B>, E, R>;
    <A, E, R, B>(ref: RefChunk<A, E, R>, f: (a: A, index: number) => B): RefSubject.Computed<Chunk.Chunk<B>, E, R>;
};
```

## Why

Projects chunk state with map values for both current reads and future pushes, avoiding a second
mutable cache of the derived value.

## Ownership and lifetime

The map values view retains no independent state. An Effect read samples the source once; Fx
observation follows later pushes and its observing Scope owns subscription cleanup.