Function computeNextRunAt

apps/sim/lib/workflows/schedules/utils.ts:65–93

(params: {
  cronExpression: string
  timezone?: string
  from?: Date
  excludedDates?: string[] | null
  endsAt?: Date | null
})

 * cron-produced occurrence time (not a rounded value) when excluding.
 */
export function computeNextRunAt(params: {
  cronExpression: string
  timezone?: string
  from?: Date
  excludedDates?: string[] | null
  endsAt?: Date | null
}): Date | null {
  const { cronExpression, timezone, from, excludedDates, endsAt } = params
  let cron: Cron
  try {
    cron = new Cron(cronExpression, timezone ? { timezone } : undefined)
  } catch {
    return null
  }

  const excluded = new Set(
    (excludedDates ?? []).map((iso) => new Date(iso).getTime()).filter((ms) => !Number.isNaN(ms))
  )

  let cursor = from ?? new Date()
  for (let i = 0; i < MAX_OCCURRENCE_SKIP; i++) {
    const next = cron.nextRun(cursor)
    if (!next) return null
    if (endsAt && next.getTime() > endsAt.getTime()) return null
    if (!excluded.has(next.getTime())) return next
    cursor = next
  }
  return null
}

interface SubBlockValue {
  value: string