format_date.ts

function padNumber(n: number): string {
  return n.toString().padStart(2, '0')
}

function formatDate(
  date: Date,
  offset?: Partial<{
    year: number
    month: number
    day: number
    hour: number
    minute: number
  }>
): string {
  const year = date.getFullYear() + (offset?.year ?? 0),
    month = padNumber(date.getMonth() + 1 + (offset?.month ?? 0)),
    day = padNumber(date.getDate() + (offset?.day ?? 0)),
    hour = padNumber(date.getHours() + (offset?.hour ?? 0)),
    minute = padNumber(date.getMinutes() + (offset?.minute ?? 0))
  return `${year}-${month}-${day}T${hour}:${minute}`
}