Moment js判断过去了多少天、几周

Question

我不太擅长处理datetime。我使用momentjs作为离子应用程序来操纵时间，但我想实现一些我无法实现的目标。

我使用了一个管道，我想根据过去了多少天、几周、几个月还是几年来显示。使用相对时间会帮助我，就像momentjsfromNow()的方法和方法calendar()一样。但就我而言，我会有多个.conditions

这是我的管道的示例代码

transform(value: Date | moment.Moment, dateFormat: string): any {
    if (moment(value) < moment(value).subtract(7, 'days')) {
      return moment(value).format('llll') // Use this format if weeks, months or years has passed
    } else if (moment(value) < moment(value).subtract(1, 'days')) {
      return moment(value).calendar(); // Use calendar time if 1 day has passed
    } else {
      return moment(value).fromNow(); // Use relative time if within 24 hours
    }
  }

如果经过几秒、几分钟或几小时直到 24 小时，我将使用该fromNow()方法，但经过几天后，我将使用该方法calendar()，如果过去了几周、几个月或几年，我将使用该方法format('llll')。

有人能给我一些启发吗？

提前致谢。

Answer 1

据我了解，您需要根据某个特定时刻距 有多远now做出决定。您似乎有 3 种情况：> 7 天，> 1 天，< 1 天。

Momentjs提供了一个非常有用的diff方法。所以，你可以这样做：

  var currDate = moment.now();
  var dateToTest = moment(val);
  // if dateToTest will always be in past, use currDate as the base to diff, else 
  be prepared to handle the negative outcomes. 
  var result = currDate.diff(dateToTest, 'days')

  var currDate = moment.now();
  var dateToTest = moment(val);
  // if dateToTest will always be in past, use currDate as the base to diff, else 
  be prepared to handle the negative outcomes. 
  var result = currDate.diff(dateToTest, 'days')

window.onload = function() {
  console.log("Test Cases: ")
  console.log("Input: Date is 2 minutes behind")
  dateThing("2018-07-20T12:02:54+00:00");
  
  console.log("Input: Date is few hours behind")
  dateThing("2018-07-20T07:02:54+00:00");
  
  console.log("Input: Date is 23 hours 59 minutes behind")
  dateThing("2018-07-19T12:03:54+00:00");
  
  console.log("Input: Date is 24 hours behind")
  dateThing("2018-07-19T12:04:54+00:00");
  
  console.log("Input: Date is 2 days behind")
  dateThing("2018-07-18T12:04:54+00:00");
  
  console.log("Input: Date is 12 days behind")
  dateThing("2018-07-08T12:04:54+00:00");
}

dateThing = function(val) {
  // for now freezing the "now" so that precise testcases can be written.
  // var currDate = moment.now();
  var currDate = moment("2018-07-20T12:04:54+00:00")
  var dateToTest = moment(val);
  // if dateToTest will always be in past, use currDate as the base to diff, else be prepared to handle the negative outcomes. 
  var result = currDate.diff(dateToTest, 'days')
  if (result > 7) {
    console.log("Output: date is more than 1 week behind")
  } else if (result > 1) {
    console.log("Output: date is more than 1 day but less than 1 week behind")
  } else {
    console.log("Output: date is less  than 1 day behind")
  }
}

请运行上面的代码片段来查看边界情况的行为，如果不准确，您可以在几分钟内进行差异并反转流程。