# isSuccess

Tests whether an AsyncData value contains a successful value.

## Signatures

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

## Why

This refinement separates settled or refreshing success from optimistic state.

## Ownership and lifetime

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

## Examples

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