js中获取当前时间，按秒更新

setInterval(()=>{
  let date= new Date();
  let y = date.getFullYear();
  let MM = date.getMonth() + 1;
    MM = MM < 10 ? (‘0‘ + MM) : MM;
  let d = date.getDate();
    d = d < 10 ? (‘0‘ + d) : d;
  let h = date.getHours();
    h = h < 10 ? (‘0‘ + h) : h;
  let m = date.getMinutes();
    m = m < 10 ? (‘0‘ + m) : m;
  let s = date.getSeconds();
    s = s < 10 ? (‘0‘ + s) : s;
  this.updateTime = y + ‘-‘ + MM + ‘-‘ + d + ‘ ‘ + h + ‘:‘ + m + ‘:‘ + s;
},1000);