fix(employees): preserve age across birthday boundaries

web/src/views/scripts/employeeManagementModel.js

@@ -303,21 +303,34 @@ export function resolveOrganizationOptions(metaOrganizations) {
     .sort((a, b) => a.name.localeCompare(b.name, 'zh-CN'))
 }
 
-export function calculateAgeFromDate(dateString) {
-  if (!dateString) {
+export function calculateAgeFromDate(dateString, referenceDate = new Date()) {
+  if (!isValidIsoDate(dateString) || !isValidReferenceDate(referenceDate)) {
     return ''
   }
 
-  const birthDate = new Date(`${dateString}T00:00:00`)
-  if (Number.isNaN(birthDate.getTime())) {
+  const [birthYearText, birthMonthText, birthDayText] = dateString.split('-')
+  const birthYear = Number.parseInt(birthYearText, 10)
+  const birthMonth = Number.parseInt(birthMonthText, 10)
+  const birthDay = Number.parseInt(birthDayText, 10)
+  const referenceYear = referenceDate.getFullYear()
+  const referenceMonth = referenceDate.getMonth() + 1
+  const referenceDay = referenceDate.getDate()
+  const referenceDateNumber = referenceYear * 10000 + referenceMonth * 100 + referenceDay
+  const birthDateNumber = birthYear * 10000 + birthMonth * 100 + birthDay
+
+  if (birthDateNumber > referenceDateNumber) {
     return ''
   }
 
-  const today = new Date()
-  let age = today.getFullYear() - birthDate.getFullYear()
+  const [birthdayMonth, birthdayDay] = normalizeBirthdayForYear(
+    birthMonth,
+    birthDay,
+    referenceYear
+  )
+  let age = referenceYear - birthYear
   const hasBirthdayPassed =
-    today.getMonth() > birthDate.getMonth() ||
-    (today.getMonth() === birthDate.getMonth() && today.getDate() >= birthDate.getDate())
+    referenceMonth > birthdayMonth ||
+    (referenceMonth === birthdayMonth && referenceDay >= birthdayDay)
 
   if (!hasBirthdayPassed) {
     age -= 1
@@ -326,31 +339,56 @@ export function calculateAgeFromDate(dateString) {
   return age >= 0 ? String(age) : ''
 }
 
-export function calculateBirthDateFromAge(ageValue, existingBirthDate = '') {
+export function calculateBirthDateFromAge(
+  ageValue,
+  existingBirthDate = '',
+  referenceDate = new Date()
+) {
   const age = Number.parseInt(String(ageValue ?? '').trim(), 10)
   if (Number.isNaN(age) || age < 0 || age > 120) {
     return existingBirthDate || ''
   }
 
-  const today = new Date()
-  let month = '01'
-  let day = '01'
+  if (!isValidReferenceDate(referenceDate)) {
+    return existingBirthDate || ''
+  }
+
+  let month = 1
+  let day = 1
 
   if (existingBirthDate && isValidIsoDate(existingBirthDate)) {
     const [, monthText, dayText] = existingBirthDate.split('-')
-    month = monthText
-    day = dayText
+    month = Number.parseInt(monthText, 10)
+    day = Number.parseInt(dayText, 10)
   }
 
-  let birthYear = today.getFullYear() - age
-  let candidate = `${birthYear}-${month}-${day}`
+  const referenceYear = referenceDate.getFullYear()
+  const referenceMonth = referenceDate.getMonth() + 1
+  const referenceDay = referenceDate.getDate()
+  const [birthdayMonth, birthdayDay] = normalizeBirthdayForYear(month, day, referenceYear)
+  const hasBirthdayPassed =
+    referenceMonth > birthdayMonth ||
+    (referenceMonth === birthdayMonth && referenceDay >= birthdayDay)
+  const birthYear = referenceYear - age - (hasBirthdayPassed ? 0 : 1)
+  const [birthMonth, birthDay] = normalizeBirthdayForYear(month, day, birthYear)
 
-  if (Number(calculateAgeFromDate(candidate)) > age) {
-    birthYear -= 1
-    candidate = `${birthYear}-${month}-${day}`
+  return `${birthYear}-${padDatePart(birthMonth)}-${padDatePart(birthDay)}`
+}
+
+function isLeapYear(year) {
+  return year % 4 === 0 && (year % 100 !== 0 || year % 400 === 0)
+}
+
+function isValidReferenceDate(value) {
+  return typeof value?.getTime === 'function' && !Number.isNaN(value.getTime())
+}
+
+function normalizeBirthdayForYear(month, day, year) {
+  if (month === 2 && day === 29 && !isLeapYear(year)) {
+    return [2, 28]
   }
 
-  return candidate
+  return [month, day]
 }
 
 export function matchKeyword(employee, keyword) {

web/tests/employee-management-age.test.mjs

@@ -0,0 +1,44 @@
+import assert from 'node:assert/strict'
+import test from 'node:test'
+
+import {
+  calculateAgeFromDate,
+  calculateBirthDateFromAge,
+  isValidIsoDate
+} from '../src/views/scripts/employeeManagementModel.js'
+
+test('根据年龄反算未到生日的出生年份不会少一年', () => {
+  const referenceDate = new Date('2026-07-18T00:00:00')
+  const birthDate = calculateBirthDateFromAge('30', '1990-12-31', referenceDate)
+
+  assert.equal(birthDate, '1995-12-31')
+  assert.equal(calculateAgeFromDate(birthDate, referenceDate), '30')
+})
+
+test('根据年龄反算已过生日的出生年份保持当年差值', () => {
+  const referenceDate = new Date('2026-07-18T00:00:00')
+  const birthDate = calculateBirthDateFromAge('30', '1990-01-01', referenceDate)
+
+  assert.equal(birthDate, '1996-01-01')
+  assert.equal(calculateAgeFromDate(birthDate, referenceDate), '30')
+})
+
+test('零岁且生日月日尚未到来时不会生成未来出生日期', () => {
+  const referenceDate = new Date('2026-07-18T00:00:00')
+  const birthDate = calculateBirthDateFromAge('0', '2000-12-31', referenceDate)
+
+  assert.equal(birthDate, '2025-12-31')
+  assert.equal(isValidIsoDate(birthDate), true)
+  assert.equal(new Date(`${birthDate}T00:00:00`) <= referenceDate, true)
+  assert.equal(calculateAgeFromDate(birthDate, referenceDate), '0')
+})
+
+test('闰日生日跨非闰年时使用二月二十八日并保持年龄回算一致', () => {
+  const referenceDate = new Date('2024-03-01T00:00:00')
+  const birthDate = calculateBirthDateFromAge('23', '2000-02-29', referenceDate)
+
+  assert.equal(birthDate, '2001-02-28')
+  assert.equal(isValidIsoDate(birthDate), true)
+  assert.equal(calculateAgeFromDate(birthDate, referenceDate), '23')
+  assert.equal(calculateAgeFromDate('2000-02-29', new Date('2023-02-28T00:00:00')), '23')
+})