Function isValidDay

telemetry-worker/src/rollup.ts:45–49

(day: string)

/** Rejects both the wrong shape and impossible dates (`2026-02-31` round-trips as `2026-03-03`). */
export function isValidDay(day: string): boolean {
  if (!/^\d{4}-\d{2}-\d{2}$/.test(day)) return false;
  const t = Date.parse(`${day}T00:00:00Z`);
  return Number.isFinite(t) && utcDay(t) === day;
}

/** Configured retention, clamped to something sane; falls back to the default. */
export function retentionDays(env: Env): number {