Obtenez des semaines en mois grâce à Javascript

Aucune des solutions proposées ici ne fonctionne pas correctement, j'ai donc écrit ma propre variante et il fonctionne pour tous les cas.

Simple et la solution de travail:

/**
 * Returns count of weeks for year and month
 *
 * @param {Number} year - full year (2016)
 * @param {Number} month_number - month_number is in the range 1..12
 * @returns {number}
 */
var weeksCount = function(year, month_number) {
    var firstOfMonth = new Date(year, month_number - 1, 1);
    var day = firstOfMonth.getDay() || 6;
    day = day === 1 ? 0 : day;
    if (day) { day-- }
    var diff = 7 - day;
    var lastOfMonth = new Date(year, month_number, 0);
    var lastDate = lastOfMonth.getDate();
    if (lastOfMonth.getDay() === 1) {
        diff--;
    }
    var result = Math.ceil((lastDate - diff) / 7);
    return result + 1;
};

vous pouvez l'essayer ici

function weeksinMonth(m, y){
 y= y || new Date().getFullYear();
 var d= new Date(y, m, 0);
 return Math.floor((d.getDate()- 1)/7)+ 1;     
}
alert(weeksinMonth(3))

//le mois de gamme pour cette méthode est de 1 (janvier)à 12(décembre)

à l'aide de moment js

function getWeeksInMonth(year, month){

        var monthStart     = moment().year(year).month(month).date(1);
        var monthEnd       = moment().year(year).month(month).endOf('month');
        var numDaysInMonth = moment().year(year).month(month).endOf('month').date();

        //calculate weeks in given month
        var weeks      = Math.ceil((numDaysInMonth + monthStart.day()) / 7);
        var weekRange  = [];
        var weekStart = moment().year(year).month(month).date(1);
        var i=0;

        while(i<weeks){
            var weekEnd   = moment(weekStart);


            if(weekEnd.endOf('week').date() <= numDaysInMonth && weekEnd.month() == month) {
                weekEnd = weekEnd.endOf('week').format('LL');
            }else{
                weekEnd = moment(monthEnd);
                weekEnd = weekEnd.format('LL')
            }

            weekRange.push({
                'weekStart': weekStart.format('LL'),
                'weekEnd': weekEnd
            });


            weekStart = weekStart.weekday(7);
            i++;
        }

        return weekRange;
    } console.log(getWeeksInMonth(2016, 7))

Grâce à Ed Pauvres pour sa solution, c'est la même que la Date de prototype.

Date.prototype.countWeeksOfMonth = function() {
  var year         = this.getFullYear();
  var month_number = this.getMonth();
  var firstOfMonth = new Date(year, month_number-1, 1);
  var lastOfMonth  = new Date(year, month_number, 0);
  var used         = firstOfMonth.getDay() + lastOfMonth.getDate();
  return Math.ceil( used / 7);
}

De sorte que vous pouvez l'utiliser comme

var weeksInCurrentMonth = new Date().countWeeksOfMonth();
var weeksInDecember2012 = new Date(2012,12,1).countWeeksOfMonth(); //6

function getWeeksInMonth(month_number, year) {
  console.log("year - "+year+" month - "+month_number+1);

  var day = 0;
  var firstOfMonth = new Date(year, month_number, 1);
  var lastOfMonth = new Date(year, parseInt(month_number)+1, 0);

  if (firstOfMonth.getDay() == 0) {
    day = 2;
    firstOfMonth = firstOfMonth.setDate(day);
    firstOfMonth = new Date(firstOfMonth);
  } else if (firstOfMonth.getDay() != 1) {
    day = 9-(firstOfMonth.getDay());
    firstOfMonth = firstOfMonth.setDate(day);
    firstOfMonth = new Date(firstOfMonth);
  }

  var days = (lastOfMonth.getDate() - firstOfMonth.getDate())+1
  return Math.ceil( days / 7);              
}

Il a travaillé pour moi. S'il vous plaît essayer

Merci à tous

    function weekCount(year, month_number, day_start) {

        //month_number is in the range 1..12
        //day_start is in the range 0..6 (where Sun=0, Mon=1, ... Sat=6)

        var firstOfMonth = new Date(year, month_number-1, 1);
        var lastOfMonth = new Date(year, month_number, 0);

        var dayOffset = (firstOfMonth.getDay() - day_start + 7) % 7;
        var used = dayOffset + lastOfMonth.getDate();

        return Math.ceil( used / 7);
    }

ES6 variante, l'utilisation cohérente de base zéro mois de l'indice. Testé pendant des années à partir de 2015 à 2025.

/**
 * Returns number of weeks
 *
 * @param {Number} year - full year (2018)
 * @param {Number} month - zero-based month index (0-11)
 * @param {Boolean} fromMonday - false if weeks start from Sunday, true - from Monday.
 * @returns {number}
 */
const weeksInMonth = (year, month, fromMonday = false) => {
    const first = new Date(year, month, 1);
    const last  = new Date(year, month + 1, 0);
    let dayOfWeek = first.getDay();
    if (fromMonday && dayOfWeek === 0) dayOfWeek = 7;
    let days = dayOfWeek + last.getDate();
    if (fromMonday) days -= 1;
    return Math.ceil(days / 7);
}