Function termDiff

src/context/approach-diff.ts:32–39

(refText: string, otherText: string, cap = 8)

/** Vocabulary diff of `other` against `ref`, compared by stem, displayed as surface words. PURE. */
export function termDiff(refText: string, otherText: string, cap = 8): TermDiff {
  const ref = surfaceByStem(refText);
  const other = surfaceByStem(otherText);
  const shared: string[] = [], added: string[] = [], missing: string[] = [];
  for (const [s, w] of other) (ref.has(s) ? shared : added).push(w);
  for (const [s, w] of ref) if (!other.has(s)) missing.push(w);
  return { shared: shared.slice(0, cap), added: added.slice(0, cap), missing: missing.slice(0, cap) };
}

/** Classic LCS line diff → unified-style lines ('  ctx' / '- old' / '+ new'). PURE. */
export function lineDiff(a: string, b: string): string[] {