# mapValues

Map values to a different type.

## Signatures

```ts
export declare const mapValues: {
    <V, B>(f: (value: V) => B): <E, R>(ref: RefHashSet<V, E, R>) => RefSubject.Computed<HashSet.HashSet<B>, E, R>;
    <V, E, R, B>(ref: RefHashSet<V, E, R>, f: (value: V) => B): RefSubject.Computed<HashSet.HashSet<B>, E, R>;
};
```

## Why

Projects hash set 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.