Nodejs Timezone Calculate getDSTTimezoneOffset()

Method Source Code

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

document.cookie = "auto_timezone_offset=" + -60 * new Date().getDSTTimezoneOffset();

Related

1. ToDfpDate(timeZoneID)

   Date.prototype.ToDfpDate = function (timeZoneID) {
     if (!isNaN(this.valueOf())) {
       return {
         date: {
           year : this.getFullYear(),
           month : this.getMonth(),
           day : this.getDate()
         },
         hour : this.getHours(),
   ...
   

2. getD(zone)

   Date.prototype.getD = function(zone) {
     zone = typeof zone !== 'undefined' ? zone : this.getTimezoneOffset();
     return Math.floor((this.getTime()-zone*60000)/86400000);
   

3. getStdTimezone()

   Date.prototype.getStdTimezone = function() {
       var jan = new Date(2015, 0, 1);
       var jul = new Date(2015, 6, 1);
       return Math.max(jan.getTimezoneOffset(), jul.getTimezoneOffset());
   

4. getTimezone()

   Date.prototype.getTimezone = function () {
       return this.toString().replace(
           /^.*? ([A-Z]{3}) [0-9]{4}.*$/, "$1").replace(
           /^.*?\(([A-Z])[a-z]+ ([A-Z])[a-z]+ ([A-Z])[a-z]+\)$/, "$1$2$3");
   

5. getTimezoneOffsetgetTimezoneOffset()

   Date.prototype.getTimezoneOffset = function getTimezoneOffset() {
     if (this._timezoneOffsetStd === undefined) {
       var date1 = new Date(this.getFullYear(), this.getMonth(), this.getDate(),
                            0,0,0,0),
           temp = date1.toGMTString(),
           date2 = new Date(temp.substring(0, temp.lastIndexOf(" ")-1));
       this._timezoneOffsetStd = (date2 - date1) / 60000;
     return this._timezoneOffsetStd;
   ...
   

6. toClientTimezone()

   Date.prototype.toClientTimezone = function () {
       var offset = new Date().getTimezoneOffset();
       this.setTime(this.getTime() + (offset * 60 * 1000));
       return this;