SEO & Sitemaps

Nix.js Kit ships helpers for the three pillars of on-page SEO: per-page metadata, structured data (JSON-LD), and sitemap/robots files. Metadata generation itself is covered in Metadata API.

# Structured data with `jsonLd`

jsonLd() returns a complete <script type="application/ld+json"> tag ready for headScripts:

// src/app/page.data.ts
import type { PageDataLoad } from "@deijose/nix-js-kit";
import { jsonLd } from "@deijose/nix-js-kit/seo";

export const load: PageDataLoad = async () => ({
  headScripts: [
    jsonLd({
      "@context": "https://schema.org",
      "@type": "WebSite",
      name: "My App",
      url: "https://my-app.dev",
    }),
  ],
});

Arrays are serialized as JSON arrays, so you can pass several schemas at once:

jsonLd([articleSchema, breadcrumbSchema]);

# Sitemap

generateSitemap() writes sitemap.xml into outDir at build time:

// scripts/gen-sitemap.ts
import { generateSitemap, generateRobots } from "@deijose/nix-js-kit/seo";

await generateSitemap({
  siteUrl: "https://my-app.dev",
  outDir: "dist",
  urls: [
    { url: "/", priority: 1.0, changefreq: "daily" },
    { url: "/about", priority: 0.5, changefreq: "monthly" },
    { url: "/blog", lastmod: "2026-01-15", priority: 0.8, changefreq: "weekly" },
    // Or just strings:
    "/contact",
  ],
});

# Robots

generateRobots() writes robots.txt:

await generateRobots({
  siteUrl: "https://my-app.dev",
  outDir: "dist",
  disallow: ["/admin", "/api"],
  // Or full per-user-agent rules:
  rules: [
    { userAgent: "*", allow: ["/"], disallow: ["/admin"] },
    { userAgent: "Googlebot", crawlDelay: 2 },
  ],
});

A Sitemap: <siteUrl>/sitemap.xml line is always appended.

# Wiring it into the build

Add a script to package.json and chain it into the build, right after the SSG step:

{
  "scripts": {
    "build": "nix-js-kit build && bun run scripts/gen-sitemap.ts"
  }
}

The script must run after nix-js-kit build so dist/ exists.

# Per-page robots control

The robots field in PageMetadata controls the <meta name="robots"> tag per page:

// src/app/page.ts
export const generateMetadata = () => ({
  title: "Admin",
  robots: "noindex, nofollow",
});

# Static-site URL conventions

On Vercel static and similar hosts, sitemap.xml and robots.txt at the root of public/ (or dist/) are served automatically — no rewrites needed.

# Availability

jsonLd, generateSitemap, generateRobots — @deijose/nix-js-kit/seo
headScripts / headLinks (favicon, manifest, theme-color) — returned by any loader, merged into <head> automatically
The SPA router persists link[rel=icon], apple-touch-icon, manifest, and theme-color across client-side navigations