# RefSubject.fromNullable

Creates Option-valued RefSubject state from a nullable input.

## Signatures

```ts
export declare function fromNullable<A>(value: A | null | undefined, options?: RefSubjectOptions<Option.Option<NonNullable<A>>>): Effect.Effect<RefSubject<Option.Option<NonNullable<A>>>, never, Scope.Scope>;
```

## Why

Converts `null` and `undefined` to `Option.none` and every other value to `Option.some`, then
stores that Option in a writable RefSubject. It does not create Filtered state or add
`NoSuchElementError`.

## Ownership and lifetime

Construction requires Scope because it delegates to `make`; it needs no services and cannot
fail. The returned RefSubject owns and publishes subsequent Option writes.