Nodejs Week Calculate getFirstDayOfWeek()

Method Source Code

Date.prototype.getFirstDayOfWeek = function()
{
    "use strict";
    var temp = new Date(this.getTime());
    var distance = (temp.getDay()-1).mod(7);
    return new Date(this.getTime() - (distance * 86400000));
};

Related

1. getDateOfISOWeek(w, y)

   Date.prototype.getDateOfISOWeek = function (w, y) {
     var simple = new Date(y, 0, 1 + (w - 1) * 7);
     var dow = simple.getDay();
     var ISOweekStart = simple;
     if (dow <= 4) ISOweekStart.setDate(simple.getDate() - simple.getDay() + 1);
     else ISOweekStart.setDate(simple.getDate() + 8 - simple.getDay());
     return ISOweekStart;
   };
   

2. getDayofWeek()

   var daysOfWeek = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];
   Date.prototype.getDayofWeek = function() {
     return daysOfWeek[this.getDay()];
   

3. getFullWeek()

   Date.prototype.getFullWeek = function(){
       var jan1, w, d = new Date(this);
       d.setDate(d.getDate()+4-(d.getDay()||7));   
       jan1 = new Date(d.getFullYear(),0,1);       
       w = Math.ceil((((d-jan1)/86400000)+1)/7);   
       return {y: d.getFullYear(), w: w };
   };
   Date.prototype.getWeek = function(){ return this.getFullWeek().w; };
   var getWeeksInYear = function(y){ return new Date(y,11,28).getFullWeek().w; };
   ...
   

4. getRealWeek()

   Date.prototype.getRealWeek = function()
       var monday = this;
       if (monday.getDay() < 1) {
           monday = monday.clone().next().monday();
       return monday.getWeek();
   };
   

5. getStudyWeek()

   Date.prototype.getStudyWeek = function () {
     var inc = (this.getDay() == 6) ? 1 : 0;
     return this.getWeek() + inc;
   };
   

6. moveToBeginOfWeek(weekStart)

   Date.prototype.moveToBeginOfWeek = function(weekStart)
       if (this.getDay() != weekStart) {
           this.moveToDayOfWeek(weekStart, -1);
       return this;
   };