Files
WRNexusJS/packages/ssr/src/index.ts
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TypeScript

/**
* @wrnexus/ssr — server-side rendering.
*
* Pages return an HTML string for the body; this module wraps that body in a
* full document with a `<head>` built from page metadata. It is intentionally
* isolated from any client runtime: nothing here touches the DOM or ships to
* the browser, which keeps "server-only code" genuinely server-only.
*/
import { escapeHtml, type PageMeta, type SeoConfig } from "@wrnexus/core";
export interface RenderOptions {
/** Page metadata for the document head. */
meta: PageMeta;
/** Global SEO defaults from `wrnexus.config.ts`. */
seo?: SeoConfig;
/** Current request URL, used to resolve canonical/Open Graph URLs. */
url?: URL;
/** Rendered HTML for the body (placed inside `#app`). */
body: string;
/**
* URLs of `<script type="module">` tags to load (e.g. per-island chunks or
* the reactive runtime). Only the scripts a page actually needs are passed.
*/
scripts?: string[];
/** Optional default document title used when meta.title is absent. */
defaultTitle?: string;
/** Raw HTML injected at the end of `<head>` (trusted, framework-controlled). */
extraHead?: string;
/** Raw HTML injected at the end of `<body>` (trusted, framework-controlled). */
extraBody?: string;
/** Attributes for the `<html>` element, e.g. ` data-theme="dark"` (trusted). */
htmlAttrs?: string;
}
/**
* Render a complete HTML document.
*
* Metadata is HTML-escaped so a malicious title/description can never break
* out of its element or attribute.
*/
export function renderDocument(opts: RenderOptions): string {
const seo = mergeSeo(opts.seo, opts.meta, opts.defaultTitle, opts.url);
const title = escapeHtml(seo.title);
const scripts = [...new Set(opts.scripts ?? [])];
const seoTags = renderSeoTags(seo);
const preloadTags = scripts
.map((src) => `\n <link rel="modulepreload" href="${escapeHtml(src)}" />`)
.join("");
const scriptTags = scripts
.map((src) => `\n <script type="module" src="${escapeHtml(src)}"></script>`)
.join("");
const extraHead = opts.extraHead ? `\n ${opts.extraHead}` : "";
const extraBody = opts.extraBody ? `\n ${opts.extraBody}` : "";
const htmlAttrs = /(?:^|\s)lang\s*=/.test(opts.htmlAttrs ?? "")
? (opts.htmlAttrs ?? "")
: `${opts.htmlAttrs ?? ""} lang="en"`;
return `<!doctype html>
<html${htmlAttrs}>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<link rel="icon" href="/favicon.ico" />
<title>${title}</title>${seoTags}${preloadTags}${extraHead}
</head>
<body>
<div id="app">${opts.body}</div>${scriptTags}${extraBody}
</body>
</html>
`;
}
interface ResolvedSeo {
title: string;
description?: string;
canonical?: string;
robots?: string;
keywords?: string;
image?: string;
siteName?: string;
type: string;
locale?: string;
twitterCard: string;
twitterSite?: string;
themeColor?: string;
}
function mergeSeo(
globalSeo: SeoConfig | undefined,
pageSeo: PageMeta,
defaultTitle: string | undefined,
url: URL | undefined,
): ResolvedSeo {
const pageTitle = pageSeo.title;
const baseTitle = pageTitle ?? globalSeo?.title ?? defaultTitle ?? "WrNexus";
const titleTemplate = pageTitle ? globalSeo?.titleTemplate : undefined;
const title = titleTemplate?.includes("%s") ? titleTemplate.replace("%s", baseTitle) : baseTitle;
const canonical = resolveSeoUrl(
pageSeo.canonical ??
globalSeo?.canonical ??
(globalSeo?.canonicalBase && url ? url.pathname : undefined),
pageSeo.canonicalBase ?? globalSeo?.canonicalBase,
url,
);
const image = resolveSeoUrl(
pageSeo.image ?? globalSeo?.image,
pageSeo.canonicalBase ?? globalSeo?.canonicalBase,
url,
);
const keywords = pageSeo.keywords ?? globalSeo?.keywords;
return {
title,
description: pageSeo.description ?? globalSeo?.description,
canonical,
robots: pageSeo.robots ?? globalSeo?.robots,
keywords: Array.isArray(keywords) ? keywords.join(", ") : keywords,
image,
siteName: pageSeo.siteName ?? globalSeo?.siteName,
type: pageSeo.type ?? globalSeo?.type ?? "website",
locale: pageSeo.locale ?? globalSeo?.locale,
twitterCard: pageSeo.twitterCard ?? globalSeo?.twitterCard ?? "summary",
twitterSite: pageSeo.twitterSite ?? globalSeo?.twitterSite,
themeColor: pageSeo.themeColor ?? globalSeo?.themeColor,
};
}
function renderSeoTags(seo: ResolvedSeo): string {
const tags: string[] = [];
if (seo.description) tags.push(meta("description", seo.description));
if (seo.robots) tags.push(meta("robots", seo.robots));
if (seo.keywords) tags.push(meta("keywords", seo.keywords));
if (seo.themeColor) tags.push(meta("theme-color", seo.themeColor));
if (seo.canonical) tags.push(`<link rel="canonical" href="${escapeHtml(seo.canonical)}" />`);
tags.push(property("og:title", seo.title));
if (seo.description) tags.push(property("og:description", seo.description));
tags.push(property("og:type", seo.type));
if (seo.canonical) tags.push(property("og:url", seo.canonical));
if (seo.siteName) tags.push(property("og:site_name", seo.siteName));
if (seo.locale) tags.push(property("og:locale", seo.locale));
if (seo.image) tags.push(property("og:image", seo.image));
tags.push(meta("twitter:card", seo.twitterCard));
tags.push(meta("twitter:title", seo.title));
if (seo.description) tags.push(meta("twitter:description", seo.description));
if (seo.image) tags.push(meta("twitter:image", seo.image));
if (seo.twitterSite) tags.push(meta("twitter:site", seo.twitterSite));
return tags.length ? `\n ${tags.join("\n ")}` : "";
}
function meta(name: string, content: string): string {
return `<meta name="${escapeHtml(name)}" content="${escapeHtml(content)}" />`;
}
function property(name: string, content: string): string {
return `<meta property="${escapeHtml(name)}" content="${escapeHtml(content)}" />`;
}
function resolveSeoUrl(
value: string | undefined,
base: string | undefined,
currentUrl: URL | undefined,
): string | undefined {
if (!value) return undefined;
try {
const origin = base ?? (currentUrl ? currentUrl.origin : undefined);
return origin ? new URL(value, origin).toString() : value;
} catch {
return value;
}
}