# RefDateTime.epochMillis

Get the epoch milliseconds of the current state of a RefDateTime.

## Signatures

```ts
export declare const epochMillis: <E, R>(ref: RefDateTime<E, R>) => RefSubject.Computed<number, E, R>;
```

## Why

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

## Ownership and lifetime

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