# RefTuple.length

Get the length of the current state of a RefTuple.

## Signatures

```ts
export declare const length: <T extends ReadonlyArray<unknown>, E, R>(ref: RefTuple<T, E, R>) => RefSubject.Computed<number, E, R>;
```

## Why

Makes length a live projection of the tuple; consumers can sample it now or observe it without
copying the source state.

## Ownership and lifetime

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