"JS- 获取星期几"

Question

我正在尝试创建一个函数来获取当前日期的一周中的所有天。我有一个我认为正在工作的函数，直到我注意到如果一周中的一天接近月底，比如例如二月，我得到奇怪的数据。 任何人都知道发生了什么以及如何解决它？

 function days(current) { var week = new Array(); // Starting Monday not Sunday var first = ((current.getDate() - current.getDay()) + 1); for (var i = 0; i < 7; i++) { week.push( new Date(current.setDate(first++)) ); } return week; } var input = new Date(2017, 1, 27); console.log('input: %s', input); var result = days(input); console.log(result.map(d => d.toString()));

 .as-console-wrapper{min-height:100%}

Answer 1

如果你不想使用像 Moment.js 这样的其他库，你也可以稍微改变你的函数，然后它就可以工作了。 试试这个：

 function dates(current) { var week= new Array(); // Starting Monday not Sunday current.setDate((current.getDate() - current.getDay() +1)); for (var i = 0; i < 7; i++) { week.push( new Date(current) ); current.setDate(current.getDate() +1); } return week; } console.log(dates(new Date(2017, 1, 27)));

Answer 2

您可以使用Moment.js库 - 用于日期/时间操作的实用程序库

这是从星期一开始获取当前日期的示例代码：

 function getThisWeekDates() { var weekDates= []; for (var i = 1; i <= 7; i++) { weekDates.push(moment().day(i)); } return weekDates; } var thisWeekDates = getThisWeekDates(); thisWeekDates.forEach(function(date){ console.log(date.format());});

 <script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.22.2/moment.js"></script>

上面的代码将以下结果打印到控制台：

2017-03-20T21:26:27+01:00
2017-03-21T21:26:27+01:00
2017-03-22T21:26:27+01:00
2017-03-23T21:26:27+01:00
2017-03-24T21:26:27+01:00
2017-03-25T21:26:27+01:00
2017-03-26T21:26:27+02:00

Answer 3

我将使用 2017 年 2 月 27 日的示例跟踪您的代码：

first = 27 - 1 + 1 = 27

loop:

Feb.setDate(27) = 27 feb
Feb.setDate(28) = 28 feb
Feb.setDate(29) = Not 29 days in Feb. So it sets current to 29-28 = 1st day of March
March.setDate(30) = March 30
March.setDate(31) = March 31     
March.setDate(32) = Not 32 days in March. So it sets current to 31-32 = 1st of April..
April.setDate(33) = Not 33 days in April. So it sets current day 33-30 = 3rd day of May. 

Answer 4

假设星期一开始一周，您可以计算星期一并转到星期日。 getDate<\/code>为您提供星期几，周日从 0 开始。对于 momnday，我们只需向前偏移 6 天即可获得周日

mondayThisWeek(date: Date): Date {
  const d = new Date(date)
  const day = d.getDay()
  const diff = d.getDate() - day + (day === 0 ? -6 : 1)
  return new Date(d.setDate(diff))
}

const offsetDate = (base: Date, count: number): Date => {
  const date = new Date(base)
  date.setDate(base.getDate() + count)
  return date
}

thisWeek(today: Date): TimeRange {
  const monday = mondayThisWeek(today)
  return {
    startDate: monday,
    endDate: offsetDate(monday, 6)
  }
}

Answer 5

这可以很容易地使用moment

 const getWeekDates = () => { let weekDates = []; for (let i = 0; i < 7; i++) weekDates.push(moment().add(i, 'd')); return weekDates; }; console.log(getWeekDates());

 <script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.22.2/moment.js"></script>