60s倒计时的实现

• 倒计时函数

• {Number} time //倒计时长 默认60

• start(star,end) 开始函数 star(a)参数a有倒计时的数字，end(b)参数b为ture，结束倒计时调用

• end(fn) 结束函数 fn结束的回调函数

  class downDate {
  constructor(time = 60) {
  this.record = time
  this.time = +time;
  this.whether = true;
  this.inter = null;
  }
  start(star, end, befor) {
  let _this = this;
  _this.whether = false;
  befor && befor(_this);
  _this.inter = setInterval(function() {
  if (_this.time <= 1) {
  _this.end();
  end && end(_this.whether);
  return
  }
  star && star(–_this.time);
  }, 1000)
  }
  end(fn) {
  this.time = this.record
  this.whether = true;
  clearInterval(this.inter);
  fn && fn();
  }
  }
  const downTime = new downDate;

  export {
  	downTime
  }