LexAI/packages/website/src/seo.ts

import faq from './faq.json';
import routesFile from './seo.routes.json';
import { CHROME_STORE, REPO, VSCODE_MARKETPLACE } from './links';

export const SITE_ORIGIN = routesFile.origin;

export type SeoRoute = {
  path: string;
  title: string;
  description: string;
  index: boolean;
};

export const INDEXABLE_ROUTES: SeoRoute[] = routesFile.routes.map((r) => ({
  ...r,
  index: true,
}));

export const NOT_FOUND_SEO: SeoRoute = {
  path: '',
  title: 'Page not found — LexAI',
  description: 'That address is not a LexAI page.',
  index: false,
};

const byPath = new Map(INDEXABLE_ROUTES.map((r) => [r.path, r]));

export function seoForPath(pathname: string): SeoRoute {
  const normalized = pathname.replace(/\/+$/, '') || '/';
  return byPath.get(normalized) ?? NOT_FOUND_SEO;
}

export function canonicalUrl(path: string): string {
  if (!path || path === '/') return `${SITE_ORIGIN}/`;
  return `${SITE_ORIGIN}${path.startsWith('/') ? path : `/${path}`}`;
}

function softwareGraph() {
  return {
    '@type': 'SoftwareApplication',
    name: 'LexAI',
    applicationCategory: 'BrowserApplication',
    applicationSubCategory: 'Writing assistance',
    operatingSystem: 'Chrome, VS Code, Windows, macOS, Linux',
    url: `${SITE_ORIGIN}/`,
    downloadUrl: [CHROME_STORE, VSCODE_MARKETPLACE],
    license: `${REPO}/src/branch/main/LICENSE`,
    sameAs: [REPO, CHROME_STORE, VSCODE_MARKETPLACE],
    offers: { '@type': 'Offer', price: '0', priceCurrency: 'USD' },
  };
}

export function jsonLdForPath(pathname: string): Record<string, unknown> {
  const seo = seoForPath(pathname);
  const url = seo.index ? canonicalUrl(seo.path) : `${SITE_ORIGIN}${pathname}`;
  const graph: unknown[] = [
    {
      '@type': 'WebSite',
      name: 'LexAI',
      url: `${SITE_ORIGIN}/`,
      description: seoForPath('/').description,
    },
    softwareGraph(),
  ];

  if (seo.path === '/') {
    graph.push({
      '@type': 'FAQPage',
      mainEntity: faq.map((item) => ({
        '@type': 'Question',
        name: item.q,
        acceptedAnswer: { '@type': 'Answer', text: item.a },
      })),
    });
  } else if (seo.index) {
    graph.push({
      '@type': 'BreadcrumbList',
      itemListElement: [
        { '@type': 'ListItem', position: 1, name: 'Home', item: `${SITE_ORIGIN}/` },
        { '@type': 'ListItem', position: 2, name: seo.title, item: url },
      ],
    });
  }

  return { '@context': 'https://schema.org', '@graph': graph };
}