// 根据出生年月（YYYY-MM-DD）计算年龄
function calcAge(birth) {
  if (!birth) return 0
  const d = new Date(birth)
  if (isNaN(d.getTime())) return 0
  const now = new Date()
  let age = now.getFullYear() - d.getFullYear()
  const m = now.getMonth() - d.getMonth()
  if (m < 0 || (m === 0 && now.getDate() < d.getDate())) age--
  return age > 0 ? age : 0
}

module.exports = { calcAge }