Nodejs Day of Year dayOfYear()

Method Source Code

// http://www.webdeveloper.com/forum/showthread.php?125428
Date.prototype.dayOfYear = function() {
  var d = new Date(); // gets today's date
  var yn = d.getFullYear();
  var mn = d.getMonth();
  var dn = d.getDate();
  var d1 = new Date(yn,0,1,12,0,0); // noon on Jan. 1
  var d2 = new Date(yn,mn,dn,12,0,0); // noon on input date
  var ddiff = Math.round((d2-d1)/864e5);
  return ddiff+1; 
}

Date.prototype.stdTimezoneOffset = function() {
  var jan = new Date(this.getFullYear(), 0, 1);
  var jul = new Date(this.getFullYear(), 6, 1);
  return Math.max(jan.getTimezoneOffset(), jul.getTimezoneOffset());
}

Date.prototype.dst = function() {
  return this.getTimezoneOffset() < this.stdTimezoneOffset();
}

Related

1. dayOfYear()

   Date.prototype.dayOfYear = function() {
      var startdayofyear = new Date(this.getFullYear(),0,1);
     return Math.ceil((this - startdayofyear) / 86400000);
   

2. getDOY()

   Date.prototype.getDOY = function() {
     var onejan = new Date(this.getFullYear(),0,1);
     return Math.ceil((this - onejan) / 86400000);
   

3. getDOY()

   Date.prototype.getDOY = function(){
     var firstOfJan = new Date(this.getFullYear(),0,1);
     return Math.ceil((this - firstOfJan) / 86400000);
   

4. getDOY()

   Date.prototype.getDOY = function() {
       var dayCount = [0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334];
       var mn = this.getMonth();
       var dn = this.getDate();
       var dayOfYear = dayCount[mn] + dn;
       if (mn > 1 && this.isLeapYear()) dayOfYear++;
       return dayOfYear;
   };
   

5. getDOY()

   ---
   ---
   Date.prototype.getDOY = function() {
     var onejan = new Date(this.getFullYear(),0,1);
     return Math.ceil((this - onejan) / 86400000);