One page identity for metadata and dates

JSON-LD is another projection of the document

The same problem appears inside a page. An h1 can name one essay while Article JSON-LD names another; an updated label can preserve the old date while the sitemap claims today. Syntax validation can accept every output. It never checked whether they agreed.

Model the publication before the vocabulary. The article record owns its headline, author, dates, image and canonical identity. A pure serializer projects those validated facts into JSON-LD, while stable absolute IDs connect the WebPage, Article and shared author. Preview hosts, random values and build hashes are poor foundations for an enduring public entity.

Vocabulary and consumer rules also need different owners. JSON-LD defines serialization, Schema.org defines terms, and a search feature has eligibility requirements. An adapter can track a consumer change without distorting the article record. Hidden or unrelated claims remain wrong even when their vocabulary validates.

The generator below removes independently edited headlines and dates from the output path. That protects agreement, while leaving a common source of error: a wrong author in the record now appears correctly serialized everywhere. Compare outputs with the manuscript and its evidence as well as with one another. A second projection of the same mistaken input is not an independent check of the fact.

function articleJsonLd(article: ArticleRecord, site: SiteConfig) {
  const url = new URL(article.canonicalPath, site.origin).href;
  return {
    "@context": "https://schema.org",
    "@type": "Article",
    "@id": `${url}#article`,
    mainEntityOfPage: { "@id": url },
    headline: article.headline,
    description: article.description,
    datePublished: article.publishedAt,
    dateModified: article.modifiedAt,
    author: { "@id": article.authorId },
    image: new URL(article.artwork.socialSrc, site.origin).href,
  };
}

A day should not acquire an invented instant

If the source says July 19, 2026, keep that precision. Serializing an invented midnight and timezone makes the data look more exact while adding a fact nobody supplied. Schema.org accepts Date or DateTime for dateModified; timed events need a declared timezone policy, while a known editorial day can remain a day. Allowed date values.

A substantial edit can change the visible updated label, Article dateModified, feed and eligible sitemap lastmod. Keep the publication date and historical source cutoff: a better explanation today does not make the research newer. A rebuild with unchanged content should advance none of those dates.

Amounts need currencies, images need reachable assets, and shared entity IDs need uniqueness or an intentional equivalence. These are domain invariants that belong before output, followed by comparisons of the built representations.