Nodejs Week Get getWeek(dowOffset)

Method Source Code

Date.prototype.getWeek = function (dowOffset) {
/*getWeek() was developed by Nick Baicoianu at MeanFreePath: http://www.meanfreepath.com */

  dowOffset = typeof(dowOffset) == 'int' ? dowOffset : 0; //default dowOffset to zero
  var newYear = new Date(this.getFullYear(),0,1);
  var day = newYear.getDay() - dowOffset; //the day of week the year begins on
  day = (day >= 0 ? day : day + 7);/*  w w w. ja v  a 2s .c om*/
  var daynum = Math.floor((this.getTime() - newYear.getTime() -
  (this.getTimezoneOffset()-newYear.getTimezoneOffset())*60000)/86400000) + 1;
  var weeknum;
  //if the year starts before the middle of a week
  if(day < 4) {
    weeknum = Math.floor((daynum+day-1)/7) + 1;
    if(weeknum > 52) {
      nYear = new Date(this.getFullYear() + 1,0,1);
      nday = nYear.getDay() - dowOffset;
      nday = nday >= 0 ? nday : nday + 7;
      /*if the next year starts before the middle of
        the week, it is week #1 of that year*/
      weeknum = nday < 4 ? 1 : 53;
    }
  }
  else {
    weeknum = Math.floor((daynum+day-1)/7);
  }
  return weeknum;
};

Related

1. getWeek()

   Date.prototype.getWeek = function () {
       var target  = new Date(this.valueOf());
       var dayNr   = (this.getDay() + 6) % 7;
       target.setDate(target.getDate() - dayNr + 3);
       var firstThursday = target.valueOf();
       target.setMonth(0, 1);
       if (target.getDay() != 4) {
           target.setMonth(0, 1 + ((4 - target.getDay()) + 7) % 7);
       return 1 + Math.ceil((firstThursday - target) / 604800000);
   

2. getWeek()

   Date.prototype.getWeek = function () {
       var determinedate = new Date();
       determinedate.setFullYear(this.getFullYear(), this.getMonth(), this.getDate());
       var D = determinedate.getDay();
       if (D == 0) D = 7;
       determinedate.setDate(determinedate.getDate() + (4 - D));
       var YN = determinedate.getFullYear();
       var ZBDoCY = Math.floor((determinedate.getTime() - new Date(YN, 0, 1, -6)) / 86400000);
       var WN = 1 + Math.floor(ZBDoCY / 7);
   ...
   

3. getWeek()

   Date.prototype.getWeek = function()
       var today = new Date(this.setHours(0, 0, 0, 0));
       var date = today.getDate() - today.getDay();
       var StartDate = new Date(today.setDate(date));
       var EndDate = new Date(today.setDate(date + 6));
       return [StartDate, EndDate];
   

4. getWeek()

   Date.prototype.getWeek = function () {
     var onejan = new Date(this.getFullYear(), 0, 1);
     var time   = this.getMilliseconds() +
                  this.getSeconds() * 1000 +
                  this.getMinutes() * 60 * 1000 +
                  this.getHours() * 60 * 60 * 1000;
     return Math.ceil((((this - onejan - time) / 86400000) + onejan.getDay() + 1) / 7);
   };
   

5. getWeek(dowOffset)

   Date.prototype.getWeek = function (dowOffset) {
       dowOffset = typeof(dowOffset) == 'int' ? dowOffset : 1; 
       var newYear = new Date(this.getFullYear(),0,1);
       var day = newYear.getDay() - dowOffset; 
       day = (day >= 0 ? day : day + 7);
     var daynum = Math.floor((this.getTime() - newYear.getTime() - 
     (this.getTimezoneOffset()-newYear.getTimezoneOffset())*60000)/86400000) + 1;
     var weeknum;
     if(day < 4) {
   ...
   

6. getWeekDayName()

   Date.prototype.getWeekDayName = function(){
     return this.weekDayName()[this.getDay()];
   };
   Date.prototype.weekDayName = function(){
     return ['Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday'];
   };
   sec = 1000;
   min = 60*sec;
   hour = 60*min;
   ...
   

7. getWeekDayName(lang)

   Date.prototype.getWeekDayName = function(lang) {
       lang = lang && (lang in Date.locale) ? lang : 'de';
       return Date.locale[lang].day_names[this.getDay()];
   };
   Date.locale = {
       de: {
           month_names: ['Januar', 'Februar', 'M?', 'April', 'Mai', 'Juni', 'Juli', 'August', 'September', 'Oktober', 'November', 'Dezember'],
           month_names_short: ['Jan', 'Feb', 'M?, 'Apr', 'Mai', 'Jun', 'Jul', 'Aug', 'Sep', 'Okt', 'Nov', 'Dez'],
           day_names: ['Sonntag', 'Montag', 'Dienstag', 'Mittwoch', 'Donnerstag', 'Freitag', 'Samstag'],
   ...
   

8. getWeekDayNameShort(lang)

   Date.prototype.getWeekDayNameShort = function(lang) {
       lang = lang && (lang in Date.locale) ? lang : 'de';
       return Date.locale[lang].day_names_short[this.getDay()];
   };
   Date.locale = {
       de: {
           month_names: ['Januar', 'Februar', 'M?', 'April', 'Mai', 'Juni', 'Juli', 'August', 'September', 'Oktober', 'November', 'Dezember'],
           month_names_short: ['Jan', 'Feb', 'M?, 'Apr', 'Mai', 'Jun', 'Jul', 'Aug', 'Sep', 'Okt', 'Nov', 'Dez'],
           day_names: ['Sonntag', 'Montag', 'Dienstag', 'Mittwoch', 'Donnerstag', 'Freitag', 'Samstag'],
   ...
   

9. getWeekNumber()

   Date.prototype.getWeekNumber = function(){
       const date = new Date(+this);
       date.setHours(0,0,0);
       date.setDate(date.getDate()+4-(date.getDay()||7));
       return Math.ceil((((date-new Date(date.getFullYear(),0,1))/8.64e7)+1)/7);
   };