# NavigationHandler

Selects optional post-commit work for a committed navigation event.

## Signatures

```ts
export type NavigationHandler<R, R2> = (event: NavigationEvent) => Effect.Effect<Option.Option<Effect.Effect<unknown, never, R2>>, never, R>;
```

## Why

Applications can update route-dependent state after history and `currentEntry` agree without
making every subscriber run for every event.

## Ownership and lifetime

Registration captures the handler's Effect context and is owned by its Scope. Selected follow-up
effects run after commit and do not alter the already committed destination.