在 Javascript 中獲取周一開始和周日結束的一周開始和結束

Question

    function getStartAndEndOfWeek(date) {

        var curr = date ? new Date(date) : new Date();
        var first = curr.getDate() - curr.getDay(); 

        var firstday = new Date(curr.setDate(first));
        var lastday = new Date(curr.setDate(firstday.getDate() + 6));

        return [firstday, lastday];

    }

我無法將一周的開始設置為星期一。 上面的代碼將第一天作為星期日。 此外，如果我們添加 first plus one，它將以星期一為開始，但問題在於讓我們說（06/29/2014，星期日）是輸入，它應該返回（06/23/2014 作為開始和 06 /29/2014) 作為結尾。 我們怎樣才能做到這一點？ 如果我添加“first + 1”，它將返回 06/30/2014 作為開始日期和 07/06/2014 作為結束日期。 有什么幫助嗎？ 謝謝。

回答：

    function getStartAndEndOfWeek(date) {

        //Calculating the starting point

        var curr = date ? new Date(date) : new Date();
        var first = curr.getDate() - dayOfWeek(curr);

        var firstday, lastday;

        if (first < 1) {
            //Get prev month and year
            var k = new Date(curr.valueOf());
            k.setDate(1);
            k.setMonth(k.getMonth() - 1);
            var prevMonthDays = new Date(k.getFullYear(), (k.getMonth() + 1), 0).getDate();

            first = prevMonthDays - (dayOfWeek(curr) - curr.getDate());
            firstday = new Date(k.setDate(first));
            lastday = new Date(k.setDate(first + 6));
        } else {
            // First day is the day of the month - the day of the week
            firstday = new Date(curr.setDate(first));
            lastday = new Date(curr.setDate(first + 6));
        }

        return [firstday, lastday];            
    }

    function dayOfWeek(date, firstDay) {
        var daysOfWeek = {
            sunday: 0,
            monday: 1,
            tuesday: 2,
            wednesday: 3,
            thursday: 4,
            friday: 5,
            saturday: 6,
        };
        firstDay = firstDay || "monday";
        var day = date.getDay() - daysOfWeek[firstDay];
        return (day < 0 ? day + 7 : day);
    }

Answer 1

如何制作一種簡單的方法來讓您輕松地控制一周的第一天：

(function() {
  var original = Date.prototype.getDay;
  var daysOfWeek = {
    sunday: 0,
    monday: 1,
    tuesday: 2,
    wednesday: 3,
    thursday: 4,
    friday: 5,
    saturday: 6,
  };

  Date.prototype.getDay = function(weekBegins) {
    weekBegins = (weekBegins || "sunday").toLowerCase();
    return (original.apply(this) + 7 - daysOfWeek[weekBegins]) % 7;
  };
})();

然后，您可以簡單地使用：

var first = curr.getDate() - curr.getDay("monday"),
    last  = first + 6;

Answer 2

您可以通過移動getDay（）的結果，然后將結果取模，首先將其設置為星期一。

var first = curr.getDate() - ((curr.getDay() + 6) % 7); 

Answer 3

簡單多了

 var numberdayweek = [6,0,1,2,3,4,5]; fecha = new Date(); console.log(numberdayweek[fecha.getDay()]);

Answer 4

找到其他解決方案：

 const getDayIndexMondaySunday = (date) =>date.getDay() === 0 ? 6 : date.getDay() - 1 // Result on Today console.log(getDayIndexMondaySunday(new Date()));