Router Options

All configuration options for createRouter(manifest, options?). Every field is optional. The router works with zero configuration.

RouterOptions

Option	Type	Default	Description
`root`	`string`	—	Base URL for resolving module `import()` paths. Pass `import.meta.url` from your server entry.
`basePath`	`string`	`'/'`	URL prefix for all routes (e.g. `'/app'`).
`csrfProtection`	`boolean \| { allowedOrigins?: string[] }`	`true`	CSRF validation on POST. Pass `false` to disable or an object with `allowedOrigins`.
`onBeforeRequest`	`(req) => Response \| void`	—	Hook called before routing. Return a Response to short-circuit.
`onNotFound`	`(req) => Response`	404 text	Hook called when no route matches.
`onError`	`(error, req) => Response`	500 text	Hook for unhandled errors. Thrown Responses never reach this hook.
`requestTimeout`	`number`	`undefined`	Max request time in ms. Exceeding returns 504. Set to 0 to disable.
`mode`	`'development' \| 'production'`	`'production'`	Controls error verbosity, module caching, and HMR injection.
`hmrUrl`	`string`	`'/@vite/client'`	Vite HMR WebSocket URL. Only used in development mode.
`assetPrefix`	`string`	`'/'`	Public URL prefix for client chunk paths.
`clientEntry`	`string`	—	Path to the client entry module that calls `hydrateRoot()`.
`streaming`	`boolean \| 'shell'`	`false`	HTML streaming mode. `false` = wait, `'shell'` = recommended, `true` = full stream.
`nonce`	`string`	—	CSP nonce for inline scripts. Passed to React's `renderToReadableStream`.
`rsc`	`boolean`	`false`	Enable RSC payload negotiation for client-side SPA navigation.
`cache`	`CacheAdapter`	—	Cross-request cache adapter for CDN or KV-level deduplication.

CacheAdapter Interface

interface CacheAdapter {
  get(key: string): unknown | Promise<unknown>;
  set(key: string, value: unknown, ttl?: number): void | Promise<void>;
}

Platform-specific implementations: Cloudflare caches.default, Redis, KV stores, or an in-memory LRU.

NavigationOptions

Options for initNavigation(setPage, options?) from @cmj/juice/client.

Option	Type	Default	Description
`viewTransitions`	`boolean`	`true`	Use the View Transitions API for page transitions.

Full Example

import { createRouter } from '@cmj/juice/runtime';
import manifest from './flight-manifest.json';

export default {
  fetch: createRouter(manifest, {
    root: import.meta.url,
    basePath: '/',
    streaming: 'shell',
    nonce: crypto.randomUUID(),
    rsc: true,
    csrfProtection: {
      allowedOrigins: ['https://admin.example.com'],
    },
    requestTimeout: 30_000,
    cache: {
      get: (key) => globalCache.get(key),
      set: (key, value, ttl) => globalCache.set(key, value, { ttl }),
    },
    onBeforeRequest: (req) => {
      if (isMaintenanceMode()) {
        return new Response('Maintenance', { status: 503 });
      }
    },
    onNotFound: (req) => {
      return new Response('Page not found', { status: 404 });
    },
    onError: (error, req) => {
      console.error('[app]', req.url, error);
      return new Response('Internal error', { status: 500 });
    },
  }),
};

File Conventions