Head

The Head component is used to render the <head> element of the document. It is used to set the title, meta tags, and other elements in the <head> of the document. Ion’s override is pretty much identical to the default Starlight Head component, the only difference being that it adds it’s own generator tag.
---
import type { z } from 'astro/zod';
import config from 'virtual:starlight/user-config';
import { version } from 'starlight-ion-theme/package.json';
import type { HeadConfigSchema } from 'starlight-ion-theme/schemas/head.js';
import { fileWithBase } from 'starlight-ion-theme/utils/base.js';
import { createHead } from 'starlight-ion-theme/utils/head.js';
import { localizedUrl } from 'starlight-ion-theme/utils/localizedUrl.js';
import type { Props } from '@astrojs/starlight/props';

const { entry, lang, siteTitle } = Astro.locals.starlightRoute;
const { data } = entry;

const canonical = Astro.site ? new URL(Astro.url.pathname, Astro.site) : undefined;
const description = data.description || config.description;

// Remove all icon brackets, their content and any whitespaces surrounding them from the title string
const titleWithoutIcons = data.title.replaceAll(/\s*\[.+\]\s*/gm, '');

const headDefaults: z.input<ReturnType<typeof HeadConfigSchema>> = [
  { tag: 'meta', attrs: { charset: 'utf-8' } },
  {
    tag: 'meta',
    attrs: { name: 'viewport', content: 'width=device-width, initial-scale=1' },
  },
  { tag: 'title', content: `${titleWithoutIcons} ${config.titleDelimiter} ${siteTitle}` },
  { tag: 'link', attrs: { rel: 'canonical', href: canonical?.href } },
  { tag: 'meta', attrs: { name: 'generator', content: Astro.generator } },
  {
    tag: 'meta',
    attrs: { name: 'generator', content: `Starlight (Ion) v${version}` },
  },
  // Favicon
  {
    tag: 'link',
    attrs: {
      rel: 'shortcut icon',
      href: fileWithBase(config.favicon.href),
      type: config.favicon.type,
    },
  },
  // OpenGraph Tags
  { tag: 'meta', attrs: { property: 'og:title', content: titleWithoutIcons } },
  { tag: 'meta', attrs: { property: 'og:type', content: 'article' } },
  { tag: 'meta', attrs: { property: 'og:url', content: canonical?.href } },
  { tag: 'meta', attrs: { property: 'og:locale', content: lang } },
  { tag: 'meta', attrs: { property: 'og:description', content: description } },
  { tag: 'meta', attrs: { property: 'og:site_name', content: siteTitle } },
  // Twitter Tags
  {
    tag: 'meta',
    attrs: { name: 'twitter:card', content: 'summary_large_image' },
  },
];

if (description)
  headDefaults.push({
    tag: 'meta',
    attrs: { name: 'description', content: description },
  });

// Link to language alternates.
if (canonical && config.isMultilingual) {
  for (const locale in config.locales) {
    const localeOpts = config.locales[locale];
    if (!localeOpts) continue;
    headDefaults.push({
      tag: 'link',
      attrs: {
        rel: 'alternate',
        hreflang: localeOpts.lang,
        href: localizedUrl(canonical, locale).href,
      },
    });
  }
}

// Link to sitemap, but only when `site` is set.
if (Astro.site) {
  headDefaults.push({
    tag: 'link',
    attrs: {
      rel: 'sitemap',
      href: fileWithBase('/sitemap-index.xml'),
    },
  });
}

// Link to Twitter account if set in Starlight config.
if (config.social?.twitter) {
  headDefaults.push({
    tag: 'meta',
    attrs: {
      name: 'twitter:site',
      content: new URL(config.social.twitter.url).pathname,
    },
  });
}

const head = createHead(headDefaults, config.head, data.head);
---
{head.map(({ tag: Tag, attrs, content }) => <Tag {...attrs} set:html={content} />)}