Jquery时间戳转换为字符串，今天，昨天，本月第一天，本周第一天。

//获取当前日期
function getTime(dateStr,pattern){
    let dt = new Date(dateStr)
    let date = shellDate(dt)
    if(pattern && pattern.toLowerCase() === 'yyyy-mm-dd'){
        return date
    }else{
        let hh = dt.getHours().toString().padStart(2,'0')
        let mm = dt.getMinutes().toString().padStart(2,'0')
        let ss = dt.getSeconds().toString().padStart(2,'0')
        return `${date} ${hh}:${mm}:${ss}`
    }
}

//获取本月第一天
function timeFormat() {
      let date = new Date()
      date.setDate(1)
      return shellDate(date)
}
//获取昨天的日期
function yesterDay(){
    let date = new Date();
    date.setTime(date.getTime()-24*60*60*1000);
    return shellDate(date)
}

//本周第一天
function weeksFirst(){
    let date=new Date();
    let nowTime = date.getTime() ;
    let day = date.getDay() || 7;//周一是每周的第一天
    //let day = date.getDay() //周日是每周的第一天
    let oneDayTime = 24*60*60*1000 ;

    let Monday = nowTime - (day-1)*oneDayTime ;
    let mondayTime=new Date(Monday);
    return shellDate(mondayTime)
}
//时间格式转换
function shellDate(date) {
    let y = date.getFullYear()
    let m = (date.getMonth()+1).toString().padStart(2, '0') 
    let d = date.getDate().toString().padStart(2,'0')
    return `${y}-${m}-${d}`
}