# RefRecord.mapEntries

Map entries to new key-value pairs.

## Signatures

```ts
export declare const mapEntries: {
    <K extends string, V, K2 extends string, B>(f: (value: V, key: K) => [
        K2,
        B
    ]): <E, R>(ref: RefRecord<K, V, E, R>) => RefSubject.Computed<Record.ReadonlyRecord<K2, B>, E, R>;
    <K extends string, V, E, R, K2 extends string, B>(ref: RefRecord<K, V, E, R>, f: (value: V, key: K) => [
        K2,
        B
    ]): RefSubject.Computed<Record.ReadonlyRecord<K2, B>, E, R>;
};
```

## Why

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

## Ownership and lifetime

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