# format

Format the current state of a RefDateTime.

## Signatures

```ts
export declare const format: {
    (options?: Intl.DateTimeFormatOptions & {
        readonly locale?: string | undefined;
    }): <E, R>(ref: RefDateTime<E, R>) => RefSubject.Computed<string, E, R>;
    <E, R>(ref: RefDateTime<E, R>, options?: Intl.DateTimeFormatOptions & {
        readonly locale?: string | undefined;
    }): RefSubject.Computed<string, E, R>;
};
```

## Why

Format the current state of a RefDateTime. The operation remains attached to the RefSubject's
versioned state boundary.

## Ownership and lifetime

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