JavaScript实现获取年月日时间的方法总结

// 获取当前时间
let currentTime = new Date();
// 获取年份
let year = currentTime.getFullYear();
// 获取月份（注意月份是从0开始计数的，所以需要加1）
let month = currentTime.getMonth() + 1;
// 获取日期
let day = currentTime.getDate();
// 获取小时
let hours = currentTime.getHours();
// 获取分钟
let minutes = currentTime.getMinutes();
// 获取秒数
let seconds = currentTime.getSeconds();
// 获取毫秒数
let milliseconds = currentTime.getMilliseconds();
// 格式化时间为 YYYY-MM-DD
let formattedDate = `${year}-${month.toString().padStart(2, '0')}-${day.toString().padStart(2, '0')}`;
// 格式化时间为 HH:MM:SS
let formattedTime = `${hours.toString().padStart(2, '0')}:${minutes.toString().padStart(2, '0')}:${seconds.toString().padStart(2, '0')}`;
// 格式化时间为 YYYY-MM-DD HH:MM:SS
let formattedDateTime = `${formattedDate} ${formattedTime}`;
// 格式化时间为 MM/DD/YYYY
let formattedDateUS = `${month.toString().padStart(2, '0')}/${day.toString().padStart(2, '0')}/${year}`;
// 格式化时间为 HH:MM AM/PM
let formattedTime12Hour = `${hours % 12 || 12}:${minutes.toString().padStart(2, '0')} ${hours < 12 ? 'AM' : 'PM'}`;
console.log('当前时间：', currentTime);
console.log('年份：', year);
console.log('月份：', month);
console.log('日期：', day);
console.log('小时：', hours);
console.log('分钟：', minutes);
console.log('秒数：', seconds);
console.log('毫秒数：', milliseconds);
console.log('格式化日期：', formattedDate);
console.log('格式化时间：', formattedTime);
console.log('格式化日期时间：', formattedDateTime);
console.log('格式化日期（美国格式）：', formattedDateUS);
console.log('格式化12小时制时间：', formattedTime12Hour);

function getMonthDates() {
  let today = new Date();
  let year = today.getFullYear();
  let month = today.getMonth();
  let startOfMonth = new Date(year, month, 1);
  let endOfMonth = new Date(year, month + 1, 0);
  let startOfLastMonth = new Date(year, month - 1, 1);
  let endOfLastMonth = new Date(year, month, 0);
  return {
    startOfMonth,
    endOfMonth,
    startOfLastMonth,
    endOfLastMonth,
  };
}
// 调用函数获取本月和上月的日期范围
let monthDates = getMonthDates();
console.log('本月的开始日期：', monthDates.startOfMonth);
console.log('本月的结束日期：', monthDates.endOfMonth);
console.log('上月的开始日期：', monthDates.startOfLastMonth);
console.log('上月的结束日期：', monthDates.endOfLastMonth);

function getQuarterDates() {
  let today = new Date();
  let year = today.getFullYear();
  let month = today.getMonth();
  let quarter = Math.floor(month / 3) + 1;
  let startOfQuarter = new Date(year, (quarter - 1) * 3, 1);
  let endOfQuarter = new Date(year, quarter * 3, 0);
  let startOfLastQuarter = new Date(year, (quarter - 2) * 3, 1);
  let endOfLastQuarter = new Date(year, (quarter - 1) * 3, 0);
  return {
    startOfQuarter,
    endOfQuarter,
    startOfLastQuarter,
    endOfLastQuarter,
  };
}
// 调用函数获取本季度和上季度的日期范围
let quarterDates = getQuarterDates();
console.log('本季度的开始日期：', quarterDates.startOfQuarter);
console.log('本季度的结束日期：', quarterDates.endOfQuarter);
console.log('上季度的开始日期：', quarterDates.startOfLastQuarter);
console.log('上季度的结束日期：', quarterDates.endOfLastQuarter);

function getLastYearDates() {
  let today = new Date();
  let year = today.getFullYear();
  let startOfYear = new Date(year - 1, 0, 1);
  let endOfYear = new Date(year - 1, 11, 31);
  return {
    startOfYear,
    endOfYear,
  };
}
// 调用函数获取上一年的日期范围
let lastYearDates = getLastYearDates();
console.log('上一年的开始日期：', lastYearDates.startOfYear);
console.log('上一年的结束日期：', lastYearDates.endOfYear);

function getDateRange() {
  let today = new Date();
  let year = today.getFullYear();
  let month = today.getMonth();
  let quarter = Math.floor(month / 3);
  let startOfMonth = new Date(year, month, 1);
  let endOfMonth = new Date(year, month + 1, 0);
  let startOfLastMonth = new Date(year, month - 1, 1);
  let endOfLastMonth = new Date(year, month, 0);
  let startOfQuarter = new Date(year, quarter * 3, 1);
  let endOfQuarter = new Date(year, quarter * 3 + 3, 0);
  let startOfLastQuarter = new Date(year, (quarter - 1) * 3, 1);
  let endOfLastQuarter = new Date(year, quarter * 3, 0);
  let startOfYear = new Date(year, 0, 1);
  let endOfYear = new Date(year, 11, 31);
  return {
    startOfMonth,
    endOfMonth,
    startOfLastMonth,
    endOfLastMonth,
    startOfQuarter,
    endOfQuarter,
    startOfLastQuarter,
    endOfLastQuarter,
    startOfYear,
    endOfYear,
  };
}
// 调用函数获取日期范围
let dateRange = getDateRange();
console.log('本月的开始日期：', dateRange.startOfMonth);
console.log('本月的结束日期：', dateRange.endOfMonth);
console.log('上月的开始日期：', dateRange.startOfLastMonth);
console.log('上月的结束日期：', dateRange.endOfLastMonth);
console.log('本季度的开始日期：', dateRange.startOfQuarter);
console.log('本季度的结束日期：', dateRange.endOfQuarter);
console.log('上季度的开始日期：', dateRange.startOfLastQuarter);
console.log('上季度的结束日期：', dateRange.endOfLastQuarter);
console.log('本年度的开始日期：', dateRange.startOfYear);
console.log('本年度的结束日期：', dateRange.endOfYear);