# Layout

A function that wraps matched content using reactive params.

## Signatures

```ts
export type Layout<Params, A, E, R, B, E2, R2> = (params: LayoutParams<Params, A, E, R>) => Fx.Fx<B, E2, R2>;
```

## Why

Layout output, errors, and services compose in the surrounding Matcher type.

## Ownership and lifetime

The executor invokes a layout only after its route is selected. Its child Scope owns the parameter/content RefSubjects and every subscription made by the returned Fx.