Nodejs Year Leap Check isLeapYear()

Method Source Code

Date.prototype.isLeapYear = function() {
    var year = this.getFullYear();
    if((year & 3) != 0) return false;
    return ((year % 100) != 0 || (year % 400) == 0);
};

// Get Day of Year
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;
};

var dayOfYear = new Date().getDOY();
console.log(dayOfYear);//from w  ww  .j  a va2 s  .  c  om

Related

1. isLeapYear()

   Date.prototype.isLeapYear = function() {
     var year = this.getFullYear();
     return !(year % 4) && (year % 100) || !(year % 400);
   

2. isLeapYear()

   Date.prototype.isLeapYear = function() {
       var year = this.getFullYear();
       if ((year & 3) != 0) return false;
       return ((year % 100) != 0 || (year % 400) == 0);
   };
   

3. isLeapYear()

   Date.prototype.isLeapYear = function () {
      return this.getFullYear()%4?0:this.getFullYear()%100?1:this.getFullYear%400?0:1
   

4. isLeapYear()

   Date.isLeapYear = function(year) {
       return (((year % 4 === 0) && (year % 100 !== 0)) || (year % 400 === 0)); 
   };
   Date.getDaysInMonth = function(year, month) {
       return [31, (Date.isLeapYear(year) ? 29 : 28), 31, 30, 31, 30, 31, 31, 30, 31, 30, 31][month];
   };
   Date.prototype.isLeapYear = function() {
       return Date.isLeapYear(this.getFullYear()); 
   };
   ...
   

5. isLeapYear()

   Date.prototype.isLeapYear = function(){
     return (0==this.getYear()%4 && ((this.getYear()%100 != 0) || (this.getYear()%400 == 0))); 
   

6. isLeapYear()

   Date.prototype.isLeapYear = function () {
       var year = this.getFullYear();
       return ((year & 3) == 0 && (year % 100 || (year % 400 == 0 && year)));
   

7. isLeapYear()

   Date.prototype.isLeapYear = function () {
     return new Date(this.getFullYear(), 1, 29).getDate() == 29;
   };