Nodejs Timezone Calculate tz(timezone)

Method Source Code

Date.prototype.tz = function(timezone) {
  var result = [], date;
  var utc = this.getTime();
  var data = data_IANA[timezone.toUpperCase()];
  if (data === undefined) {
    data = data_abbr[timezone.toUpperCase()];
  }/*from ww  w.  ja  v  a  2  s.  com*/

  if (data !== undefined && data.constructor === String) {
    date = utc + (+data.split(':')[0] * 60 * 60 * 1000) + (((+data.split(':')[1]||0) * 60 * 1000) * (+data.split(':')[0] < 0 ? -1 : 1));
    result.push(new Date(date).toISOString());
  } else if (data !== undefined && data.constructor === Object) {
    for (var i in data) { 
      date = utc + (+i.split(':')[0] * 60 * 60 * 1000) + (((+i.split(':')[1]||0) * 60 * 1000) * (+i.split(':')[0] < 0 ? -1 : 1));
      result.push(new Date(date).toISOString() + '|(' + data[i] + ')');
    }
  }

  return result;
};

Related

1. 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());
   

2. 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");
   

3. 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;
   ...
   

4. toClientTimezone()

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

5. toServerTimezone()

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