javascript - 如何获得直到 X 日期的天数并在 X 日期达到 0 时停止计数

Question

此代码已经获取到 x 日期的天数，但是当 x 日期达到相同日期时它会继续计数，我怎样才能将它归零以停止计数？

const counters = this.state.counters.map((counters, i) => {
  let untildate = counters.date
  let diffDays1=(function(){ 
    let oneDay = 24*60*60*1000 // hours*minutes*seconds*milliseconds
    let secondDate = new Date(untildate);
    let firstDate = new Date();
    return (`${Math.round(Math.abs((firstDate.getTime() - secondDate.getTime())/(oneDay)))} Days`)
  })();

如果输入日期是 2019-04-05T20:00:00.782Z 输出应该是 0

Answer 1

使用Math.max返回两个值中较大的一个。在您的例子中，您希望仅在该数字大于 0 时返回剩余天数，否则您希望返回 0:

const counters = this.state.counters.map((counters, i) => {
  let untildate = counters.date
  let diffDays1=(function(){ 
    let oneDay = 24*60*60*1000 // hours*minutes*seconds*milliseconds
    let secondDate = new Date(untildate);
    let firstDate = new Date();
    return (`${Math.max(0, Math.round(Math.abs((firstDate.getTime() - secondDate.getTime())/(oneDay))))} Days`)
  })();