# Fx.succeedUndefined

An Fx that emits `undefined` exactly once and then completes.

## Signatures

```ts
export declare const succeedUndefined: Fx<undefined, never, never>;
```

## Why

The shared constant avoids repeatedly spelling `succeed(undefined)` in optional
compositions. It is also exported as `undefined`.

## Ownership and lifetime

Each run performs one sink delivery and acquires no resources.

## Examples

```ts
import { first, succeedUndefined } from "@typed/fx/Fx"

const program = first(succeedUndefined)
```