# RefCause.isEmpty

Check if the current state of a RefCause is empty.

## Signatures

```ts
export declare const isEmpty: <E, Err, R>(ref: RefCause<E, Err, R>) => RefSubject.Computed<boolean, Err, R>;
```

## Why

Makes is empty a live projection of the cause; consumers can sample it now or observe it without
copying the source state.

## Ownership and lifetime

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