# isOptimistic

Tests whether an AsyncData value is an optimistic history node.

## Signatures

```ts
export declare const isOptimistic: <A, E>(asyncData: AsyncData<A, E>) => asyncData is Optimistic<A, E>;
```

## Why

A dedicated refinement makes history traversal explicit and type safe.

## Ownership and lifetime

This pure predicate acquires no resources and does not retain its argument.

## Examples

```ts
import { isOptimistic, optimistic, success } from "@typed/async-data"
isOptimistic(optimistic(success(1), 2))
```