日期减去日期没有给出所需的答案-Ionic 2

Question

当我尝试减去

时

Wed Dec 06 2017 15:58:59 GMT+0530 (India Standard Time)减去Tue Nov 28 2017 00:00:00 GMT+0530 (India Standard Time)，即将到来的答案是 -22

但答案应为 6

出了什么问题，下面是我的page.ts代码：

  this.tt = new Date();
  this.tt1 = this.datePipe.transform(this.tt,'dd/mm/yyyy');
  console.log(this.ent[0],"server DATE");
  // in console we see this - 28-NOV-17 server DATE
  var firstDate= new Date(this.ent[0]);  //Jan 01 2017 00:00:00
  var secondDate = new Date();//Jan 04 2017 00:00:00
  console.log(firstDate); 
 // answer in console - Tue Nov 28 2017 00:00:00 GMT+0530 (India Standard Time)
  console.log(secondDate);
 //answer in console - Wed Dec 06 2017 15:58:59 GMT+0530 (India Standard Time)
  console.log(secondDate.getDate() - firstDate.getDate() );
 //answer in console -  -22

Answer 1

date.getDate（）给出日期的" dd"（在您的情况6和28中，将结果解释为-22）。我对预期结果有点困惑6.所以也许我的答案不适合您。但是，我要做的是转换日期，进行缩写并将其转换回天数。

so

Math.Floor((secondDate.getTime() - firstDate.getTime()) / 86400000);
(86400000 being 1000 (milliseconds) * 3600 (seconds in an hour) * 24 (number of hours in a day)

Answer 2

您可以将日期转换为时间戳并减去时间戳，您将在Millis中获得结果的日子，现在将其转换为天

getTimestamp(dateParam:string):string{
    var date = new Date(dateParam); // some mock date
    var milliseconds = date.getTime(); 
    return milliseconds.toString();
} 
var one_day=1000*60*60*24;
console.log(Math.ceil(getTimestamp(secondDate) - getTimestamp(firstDate))/(one_day) );