JS实现判断两个日期不能跨年和跨月

const date1 = new Date('2023-01-08');
const date2 = new Date('2023-02-08');

if (date1.getFullYear() !== date2.getFullYear() || date1.getMonth() !== date2.getMonth()) {
  console.log('日期跨年或跨月');
} else {
  console.log('日期不跨年也不跨月');
}

const dateString1 = '20230108';
const dateString2 = '20230208';

const date1 = new Date(`${dateString1.slice(0, 4)}-${dateString1.slice(4, 6)}-${dateString1.slice(6, 8)}`);
const date2 = new Date(`${dateString2.slice(0, 4)}-${dateString2.slice(4, 6)}-${dateString2.slice(6, 8)}`);

if (date1.getFullYear() !== date2.getFullYear() || date1.getMonth() !== date2.getMonth()) {
  console.log('日期跨年或跨月');
} else {
  console.log('日期不跨年也不跨月');
}

const dateString1 = '20230108';
const dateString2 = '20230208';

if (dateString1.slice(0, 6) !== dateString2.slice(0, 6)) {
  console.log('日期跨年或跨月');
} else {
  console.log('日期不跨年也不跨月');
}

function isValidDateFORMat(dateStr, formatStr) {
  const regex = new RegExp(formatStr);
  return regex.test(dateStr);
}

function datesAreInSameMonthAndYear(dateStr1, dateStr2, formatStr) {
  if (!isValidDateFormat(dateStr1, formatStr) || !isValidDateFormat(dateStr2, formatStr)) {
    return false; // 如果日期字符串不符合指定的格式，则返回false
  }

  // 将日期字符串转换为Date对象
  const date1 = new Date(dateStr1.slice(0, 4), dateStr1.slice(4, 6) - 1, dateStr1.slice(6));
  const date2 = new Date(dateStr2.slice(0, 4), dateStr2.slice(4, 6) - 1, dateStr2.slice(6));

  // 检查日期是否在同一年和同一月
  return (date1.getFullYear() === date2.getFullYear() && date1.getMonth() === date2.getMonth());
}

function isValidDateFormat(dateStr, formatStr) {
  const regex = new RegExp(formatStr);
  return regex.test(dateStr);
}

const dateStr1 = '20230108';
const dateStr2 = '20230208';
const formatStr = '\d{4}\d{2}\d{2}';

if (datesAreInSameMonthAndYear(dateStr1, dateStr2, formatStr)) {
  console.log(`${dateStr1} and ${dateStr2} are in the same year and month.`);
} else {
  console.log(`${dateStr1} and ${dateStr2} are not in the same year and month.`);
}