# CurrentRoute

The ambient route context for the current routing boundary.

## Signatures

```ts
export declare class CurrentRoute extends CurrentRoute_base {
    static readonly Default: Layer.Layer<CurrentRoute, never, Navigation>;
    static readonly extend: (route: Route.Any) => Layer.Layer<CurrentRoute, never, never>;
}
```

## Why

A stable ambient context prevents same-route parameter updates from replacing structural ownership.
Use Navigation for the live URL; use CurrentRoute for the route tree that owns this handler.

## Ownership and lifetime

The selected handler or layout Scope owns the provided service. `Default` creates the root from
`Navigation.base`; `extend` shadows it for a nested boundary and retains the previous value as parent.

## Property: Default

Provides the root mount route parsed from `Navigation.base`.

## Property: Default: Why

Every router needs a structural root even before a matcher selects a child route.

## Property: Default: Ownership and lifetime

The Layer borrows Navigation and provides CurrentRoute for its surrounding Layer Scope.

## Property: extend

Provides a nested CurrentRoute whose parent is the ambient mount boundary.

## Property: extend: Why

An independently owned child Matcher declares paths relative to this mount. The supplied
Route is the exact child mount, not an automatically joined relative segment; compose deeper
prefixes with `Route.Join` before extending. Navigation remains shared with the surrounding app.

## Property: extend: Ownership and lifetime

Layer acquisition reads the ambient context once. The returned child tree lives until that Layer Scope closes.

## Examples

```ts
import * as Router from "@typed/router"
import * as Effect from "effect/Effect"

const mountedPath = Effect.map(Router.CurrentRoute, ({ route }) => route.path)
```