# useBlockNavigation

Registers a scoped navigation blocker and returns renderer-independent blocking state.

## Signatures

```ts
export declare const useBlockNavigation: <R = never>(params?: UseBlockNavigationParams<R>) => Effect.Effect<BlockNavigation, never, Navigation | R | Scope.Scope>;
```

## Why

Unsaved-work flows need to pause navigation without replacing the provider or forcing state into a
UI component. At most one transition is outstanding; later attempts are not independently queued.

## Ownership and lifetime

The required Scope owns the before-navigation registration, RefSubject, and deferred settlement.
Scope closure cancels an outstanding transition and finalizes the registration. Consumers must
observe and settle the returned state inside that owning Scope.

## Examples

```ts
import { useBlockNavigation } from "@typed/navigation/Blocking"
import * as Effect from "effect/Effect"

const blocker = useBlockNavigation({ shouldBlock: () => Effect.succeed(true) })
```

Scope behavior follows Effect v4 resource management:
https://effect.website/docs/resource-management/scope/.