js获取时间

// 获取昨天的时间
var time = (new Date).getTime() - 24 * 60 * 60 * 1000;
var yesterday = new Date(time);
var month0 = yesterday.getMonth();
var day0 = yesterday.getDate();
yesterday = yesterday.getFullYear() + "-" + (yesterday.getMonth() > 9 ? (yesterday.getMonth() + 1) : "0" + (yesterday.getMonth() + 1)) + "-" + (yesterday.getDate() > 9 ? (yesterday.getDate()) : "0" + (yesterday.getDate()));
console.log(yesterday);
// 获取今天的时间
var myDate = new Date(); //获取当前年份(2位)
var year=myDate.getFullYear(); //获取完整的年份(4位,1970-????)
var month1=myDate.getMonth()>9?(myDate.getMonth()+1):"0"+(myDate.getMonth()+1); //获取当前月份(0-11,0代表1月)
var day1=myDate.getDate()>9?myDate.getDate():"0"+myDate.getDate(); //获取当前日(1-31)
var dayNow=year+ '-' + month1 + "-" +day1;
console.log(dayNow);
// 获取上个月
var time1 = (new Date).getTime() - 24 * 60 * 60 * 1000 * 30;
var yesterday1 = new Date(time1);
var month2 = yesterday1.getMonth();
var day2 = yesterday1.getDate();
yesterday1 = yesterday1.getFullYear() + "-" + (yesterday1.getMonth() > 9 ? (yesterday1.getMonth() + 1) : "0" + (yesterday1.getMonth() + 1)) + "-" + (yesterday1.getDate() > 9 ? (yesterday1.getDate()) : "0" + (yesterday1.getDate()));
console.log(yesterday1);
// 获取上个月最后一天
date = new Date();
date.setDate(0); //setDate(day) 方法用于设置一个月的某一天。day取1-31表示对应的天数，另外0 为上一个月的最后一天，-1 为上一个月最后一天之前的一天，32 为下个月的第一天或者第二天
var year1 = date.getFullYear();
var month3 = date.getMonth()+1;
month3 = month3 > 9 ? month3:'0'+month3;
var day3 = date.getDate(); //getDate() 方法可返回月份的某一天。也就是当前date的当前天数
day3 = day3 > 9 ? day3:'0'+day3;
console.log(year1+ '-' + month3 + "-" +day3)

// 将日期转化为毫秒
const date_ = new Date(2021, 12, 9).getTime()
console.log(date_)