lit-ui-router-ssr / prerender

Function: prerender()

function prerender(options): Promise<PrerenderResult>;

Defined in: packages/lit-ui-router-ssr/src/prerender.ts:444

Emits a static site from a mount table's verdicts: a shell verdict becomes <subpath>/index.html, a redirect becomes a rules line and no page, and the otherwise projection becomes the 404 document.

The router is provided on the render root for context-request and scoped with withRouterSync around each render, so a template's <ui-router> descendants and its sref attribute directives read the same router. Renders run one at a time: the scope is a module slot, so there is nothing to parallelise.

A rendered page opens on its hydration signature: a JSON data block, <script type="application/json" data-lit-ui-router-ssr>, naming this package's version and the state and parameter values the router stood on, which hydrateRoot() reads before it touches the document. A renderShell that returns a string is written as-is, with no signature, so the client renders it cold.

Pages are rendered with deferHydration, so every custom element one holds carries defer-hydration and renders nothing until hydrateRoot()'s walk reaches it on the client. A property binding emits only its part marker: the property is set when the page hydrates, so what an element must show on the served page arrives as an attribute or as children.

Parameters

Parameter	Type	Description
options	PrerenderOptions	the mount table, the router, the paths, and the hooks

Returns

Promise<PrerenderResult>

what was emitted, planned or written

Throws

an Error when neither mounts nor resolver is supplied

Example

const result = await prerender({
  mounts,
  router,
  outDir: 'dist',
  paths: ['/', '/sheet/7B', '/legacy'],
  renderShell: async (verdict, { path }) => {
    await settle(router, path);
    return page();
  },
  document: (body, { path }) => fillShell(titles.get(path), body),
});