Question

我们如何获取本月的所有星期开始日期和结束日期？

下面的代码仅显示当前星期的开始日期和结束日期

var startOfWeek = moment().startOf("isoWeek").toDate();
var endOfWeek = moment().endOf("isoWeek").toDate();
console.log(startOfWeek)
console.log(endOfWeek)

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Answer 1

只需在当前月份添加/减去7天，即可获得后续和之前的几周的信息。

let current = startOfWeek;

do {
  current = current.subtract(7, "days");  //or .add(7, "days") to get next week
} while (current.month() === startOfWeek.month())

Answer 2

这有趣吗？ -不浪费时间

不确定从第一天开始还是下个月结束的几周要做什么

const d = new Date(),
month = d.getMonth(),
yyyy = d.getFullYear(),
end = new Date(yyyy,month+1,0).getDate();
const startEnd = Array.from(Array(end+1).keys()).slice(1)
  .reduce((acc,day) => {
  const d = new Date(yyyy,month,day,15,0,0,0);
  if (d.getDay() === 1) acc.push({start:d});
  else if (d.getDay() === 6 && acc[acc.length-1]) acc[acc.length-1]["end"] = d;
  return acc
},[])

console.log(startEnd)

Answer 3

该问题涉及ISO周，因此我想您希望当月的任何ISO周都在当月。您可以通过以下操作来实现：每月的1号，设置为上一个星期一（如果是星期一，则设置为同一天），然后在数周内进行迭代，直到到达下个月。例如

// Month is calendar month number
function getISOWeeksInMonth(month = new Date().getMonth() + 1, year = new Date().getFullYear()) {
  // Start at 1st of month
  let weekStart = new Date(year, month - 1, 1);
  // Set to prior Monday
  weekStart.setDate(weekStart.getDate() - (weekStart.getDay() || 7) + 1);
  // Get end of week
  let weekEnd = new Date(weekStart);
  weekEnd.setDate(weekEnd.getDate() + 6);
  // Get week number of 1st week
  let weekNum = getWeekNumber(weekStart)[1];
  // Create weeks array
  let weeks = [];
  while (weekStart.getMonth() < month) {
    weeks.push({
      weekNum : weekNum++,
      start: new Date(weekStart),
      end: new Date(weekEnd)
    });
    weekStart.setDate(weekStart.getDate() + 7);
    weekEnd.setDate(weekEnd.getDate() + 7);
  }
  return weeks;
}

// Get ISO week number - from https://stackoverflow.com/a/6117889/257182
function getWeekNumber(d) {
    d = new Date(Date.UTC(d.getFullYear(), d.getMonth(), d.getDate()));
    d.setUTCDate(d.getUTCDate() + 4 - (d.getUTCDay()||7));
    var yearStart = new Date(Date.UTC(d.getUTCFullYear(),0,1));
    var weekNo = Math.ceil(( ( (d - yearStart) / 86400000) + 1)/7);
    return [d.getUTCFullYear(), weekNo];
}

// ISO weeks of current month
getISOWeeksInMonth().forEach(week => console.log(
   'Week : ' + week.weekNum +
   '\nStart: ' + week.start.toDateString() + 
   '\nEnd  : ' + week.end.toDateString())
);

// ISO weeks in Feb 2021 (starts on a Monday)
getISOWeeksInMonth(2, 2021).forEach(week => console.log(
   'Week : ' + week.weekNum +
   '\nStart: ' + week.start.toDateString() + 
   '\nEnd  : ' + week.end.toDateString())
);

如何获取所有星期的开始日期和结束日期

3 个答案: