---
url: >-
  https://lit-ui-router.dev/api/lit-ui-router-ssr/vite/interfaces/ServerRouterPluginOptions.md
---
[lit-ui-router-ssr](../../index.md) / [vite](../index.md) / ServerRouterPluginOptions

# Interface: ServerRouterPluginOptions

Defined in: [packages/lit-ui-router-ssr/src/vite.ts:37](https://github.com/simshanith/lit-ui-router/blob/ef3e46636efc18ec90dbba19adacfdffe05f88f4/packages/lit-ui-router-ssr/src/vite.ts#L37)

`ui-router-server/vite`'s plugin options, plus the DOM the prerender
worker installs for Lit.

## Extends

* `ServerRouterPluginOptions`

## Properties

| Property | Type | Description | Inherited from | Defined in |
| ------ | ------ | ------ | ------ | ------ |
|  `delegates?` | `"next"` | How delegating states are served. Connect has no fetch-shaped handler bridge, so `'next'` is the only mode: a navigation that matches a delegating state passes to the downstream stack, which must serve it. Without it, construction throws for a router from `createServerRouter` that names delegate keys, and a structural router's delegate verdict fails the request through `next(error)`. | `SiteRouterPluginOptions.delegates` | packages/ui-router-server/dist/connect.d.ts:75 |
|  `prerender?` | `string` | `PrerenderOptions` | Prerenders the app after `vite build`. `entry` names the prerender script, resolved against Vite's root, whose default export is a [PrerenderEntry](../type-aliases/PrerenderEntry.md); a string is shorthand for `{ entry }`. The script runs in a `worker_thread` of its own, after any [preload](/api/ui-router-server/vite/interfaces/PrerenderOptions#preload) modules, so nothing it installs reaches Vite's process. It is loaded through a Vite module runner with the root and mode, without the app's plugins, and its dependencies load from node. `vite preview` then serves each page the build wrote, and `404.html` for a path the `otherwise` rule sends to a 404 state, while redirects and plain 404s still answer through the middleware. A [serveShell](#serveshell) passed here replaces that. **See** https://lit-ui-router.dev/guides/prerender-with-vite | `SiteRouterPluginOptions.prerender` | packages/ui-router-server/dist/vite.d.ts:89 |
|  `responses?` | `"next"` | How response states are served, as for [delegates](#delegates): `'next'` passes a navigation that matches one to the downstream stack, which must answer it. Without it, construction throws for a router from `createServerRouter` that declares response states, and a structural router's response verdict fails the request through `next(error)`. | `SiteRouterPluginOptions.responses` | packages/ui-router-server/dist/connect.d.ts:83 |
|  `serveNotFound?` | (`mount`, `req`, `res`, `next`) => `void` | Serve a mount-owned miss (`notFound` with a mount: the mount owned the pathname but no route matched). The default answers a minimal `text/plain` 404 — override to serve a real 404 page. A `notFound` without a mount is never routed here: the pathname isn't this router's, so the middleware always passes it through untouched. | `SiteRouterPluginOptions.serveNotFound` | packages/ui-router-server/dist/connect.d.ts:56 |
|  `serveShell?` | (`mount`, `req`, `res`, `next`, `verdict`) => `void` | Serve the mount's shell. The default rewrites `req.url` to [shellPath](#shellpath) and `next()`s into the downstream static layer. By the time this runs the adapter has already done the status'd-shell mechanics: request validators stripped and the response relabeled to the verdict's status — a host override only owns the asset IO. The verdict arrives last, so a host can serve a 404 page for the `otherwise` projection's `status`. | `SiteRouterPluginOptions.serveShell` | packages/ui-router-server/dist/connect.d.ts:48 |
|  `shellPath?` | (`mount`) => `string` | Maps a shell verdict's mount to the path the default [serveShell](#serveshell) rewrites `req.url` to (default: the mount base itself). The hook for aliased mounts whose shell lives under another prefix. | `SiteRouterPluginOptions.shellPath` | packages/ui-router-server/dist/connect.d.ts:38 |
|  `shim?` | readonly `string`\[] | Modules that install a DOM in the prerender worker, loaded in order before `lit-ui-router-ssr/register` and any `preload`. Defaults to `@lit-labs/ssr`'s DOM shim. List another DOM's setup to use it instead, or pass `[]` to install none: Lit's Node build still renders, but app code that reads `document` or `window` fails. | - | [packages/lit-ui-router-ssr/src/vite.ts:45](https://github.com/simshanith/lit-ui-router/blob/ef3e46636efc18ec90dbba19adacfdffe05f88f4/packages/lit-ui-router-ssr/src/vite.ts#L45) |
|  `shouldHandle?` | (`req`) => `boolean` | Which requests get verdicts. The default is the navigation heuristic `connect-history-api-fallback` established (and Vite's own HTML fallback mirrors): GET/HEAD requests whose Accept includes `text/html`. Module and asset fetches (`Accept: *​/*`) pass through untouched — essential under Vite, where a mount's module URLs live on the same paths as its routes. Override with `() => true` when the middleware sits behind the static layer and should judge everything. | `SiteRouterPluginOptions.shouldHandle` | packages/ui-router-server/dist/connect.d.ts:66 |