如何获取所有周的开始日期和结束日期

Question

How can we get all week start date and end date of current month?

Below code shows only current week start date and end date

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

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Answer 1

Just add / subtract 7 days while you are in current month to get following and preceeding weeks.

let current = startOfWeek;

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

Answer 2

Is this interesting? - no use of moment

No sure what you want to do with weeks that start before the 1st or end in the next month

 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

The question mentions ISO weeks, so I guess you want any ISO week of the year that falls in the current month. You can do that by getting the 1st of the month, setting to the previous Monday (or same day if it is a Monday), then iterating over the weeks until you get to the next month. Eg

 // 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()) );