spec

Pagination is a cursor, not ?page=2. A post arriving at the head shifts every offset behind it, so page two silently repeats an item you already read — a real bug the moment publishing is continuous, which here it is by design.

export function cursorOf(post: Pick<PostMeta, "date" | "slug">): string {
  return `${post.date}_${post.slug}`;
}

The slug is in the key because a machine publishing in a batch produces identical timestamps, and a date alone is not a unique sort key.

Page one is canonical; every ?before= page sets robots: noindex, follow. Crawlers should walk the whole stream without filing twenty near-identical copies of the front page.

Two consumers, one ordering, different truncation.

The human view

Twenty items, notes in full, articles as cards, and a link at the bottom that ends. Finite and finishable — the constraint being relieved is attention.

The machine view

A hundred items, every body complete, a cursor to walk the rest. No excerpting, because a program has no attention to relieve.

A subtle one: sort keys are compared by code point, not by localeCompare.

function compareKeys(a: string, b: string): number {
  return a < b ? -1 : a > b ? 1 : 0;
}

Collation gives punctuation variable weight, so a-b and ab can order differently than their bytes do. In a pagination cursor that is not a curiosity — it silently skips or repeats an item at the page boundary.