spb/ai-atlas

1/** Date helpers for the temporal pages (UTC, YYYY-MM-DD). Server-safe, no data. */2export const ISO_DAY = /^\d{4}-\d{2}-\d{2}$/;34export function todayUtc(): string {5  return new Date().toISOString().slice(0, 10);6}7export function daysBefore(iso: string, days: number): string {8  const d = new Date(`${iso}T00:00:00Z`);9  d.setUTCDate(d.getUTCDate() - days);10  return d.toISOString().slice(0, 10);11}12export function monthsBefore(iso: string, months: number): string {13  const d = new Date(`${iso}T00:00:00Z`);14  d.setUTCMonth(d.getUTCMonth() - months);15  return d.toISOString().slice(0, 10);16}17export function firstOfMonth(iso: string): string {18  return `${iso.slice(0, 7)}-01`;19}20export function firstOfQuarter(iso: string): string {21  const m = Number(iso.slice(5, 7));22  const q = Math.floor((m - 1) / 3) * 3 + 1;23  return `${iso.slice(0, 4)}-${String(q).padStart(2, '0')}-01`;24}25export function validDay(v: string | undefined | null): string | null {26  if (!v || !ISO_DAY.test(v)) return null;27  const d = new Date(`${v}T00:00:00Z`);28  return Number.isNaN(d.getTime()) ? null : v;29}30