Jquery时间戳转换为字符串，今天，昨天，本月第一天，本周第一天。

 1 //获取当前日期
 2 function getTime(dateStr,pattern){
 3     let dt = new Date(dateStr)
 4     let date = shellDate(dt)
 5     if(pattern && pattern.toLowerCase() === 'yyyy-mm-dd'){
 6         return date
 7     }else{
 8         let hh = dt.getHours().toString().padStart(2,'0')
 9         let mm = dt.getMinutes().toString().padStart(2,'0')
10         let ss = dt.getSeconds().toString().padStart(2,'0')
11         return `${date} ${hh}:${mm}:${ss}`
12     }
13 }
14 
15 //获取本月第一天
16 function timeFormat() {
17       let date = new Date()
18       date.setDate(1)
19       return shellDate(date)
20 }
21 //获取昨天的日期
22 function yesterDay(){
23     let date = new Date();
24     date.setTime(date.getTime()-24*60*60*1000);
25     return shellDate(date)
26 }
27 
28 //本周第一天
29 function weeksFirst(){
30     let date=new Date();
31     let nowTime = date.getTime() ;
32     let day = date.getDay() || 7;//周一是每周的第一天
33     //let day = date.getDay() //周日是每周的第一天
34     let oneDayTime = 24*60*60*1000 ;
35 
36     let Monday = nowTime - (day-1)*oneDayTime ;
37     let mondayTime=new Date(Monday);
38     return shellDate(mondayTime)
39 }
40 //时间格式转换
41 function shellDate(date) {
42     let y = date.getFullYear()
43     let m = (date.getMonth()+1).toString().padStart(2, '0') 
44     let d = date.getDate().toString().padStart(2,'0')
45     return `${y}-${m}-${d}`
46 }