359 lines
14 KiB
JavaScript
359 lines
14 KiB
JavaScript
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/**
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* This script gives you the zone info key representing your device's time zone setting.
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*
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* @name jsTimezoneDetect
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* @version 1.0.5
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* @author Jon Nylander
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* @license MIT License - http://www.opensource.org/licenses/mit-license.php
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*
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* For usage and examples, visit:
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* http://pellepim.bitbucket.org/jstz/
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*
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* Copyright (c) Jon Nylander
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*/
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/*jslint undef: true */
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/*global console, exports*/
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(function(root) {
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/**
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* Namespace to hold all the code for timezone detection.
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*/
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var jstz = (function () {
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'use strict';
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var HEMISPHERE_SOUTH = 's',
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/**
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* Gets the offset in minutes from UTC for a certain date.
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* @param {Date} date
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* @returns {Number}
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*/
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get_date_offset = function (date) {
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var offset = -date.getTimezoneOffset();
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return (offset !== null ? offset : 0);
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},
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get_date = function (year, month, date) {
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var d = new Date();
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if (year !== undefined) {
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d.setFullYear(year);
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}
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d.setMonth(month);
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d.setDate(date);
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return d;
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},
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get_january_offset = function (year) {
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return get_date_offset(get_date(year, 0 ,2));
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},
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get_june_offset = function (year) {
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return get_date_offset(get_date(year, 5, 2));
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},
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/**
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* Private method.
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* Checks whether a given date is in daylight saving time.
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* If the date supplied is after august, we assume that we're checking
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* for southern hemisphere DST.
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* @param {Date} date
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* @returns {Boolean}
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*/
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date_is_dst = function (date) {
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var is_southern = date.getMonth() > 7,
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base_offset = is_southern ? get_june_offset(date.getFullYear()) :
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get_january_offset(date.getFullYear()),
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date_offset = get_date_offset(date),
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is_west = base_offset < 0,
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dst_offset = base_offset - date_offset;
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if (!is_west && !is_southern) {
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return dst_offset < 0;
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}
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return dst_offset !== 0;
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},
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/**
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* This function does some basic calculations to create information about
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* the user's timezone. It uses REFERENCE_YEAR as a solid year for which
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* the script has been tested rather than depend on the year set by the
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* client device.
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*
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* Returns a key that can be used to do lookups in jstz.olson.timezones.
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* eg: "720,1,2".
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*
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* @returns {String}
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*/
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lookup_key = function () {
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var january_offset = get_january_offset(),
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june_offset = get_june_offset(),
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diff = january_offset - june_offset;
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if (diff < 0) {
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return january_offset + ",1";
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} else if (diff > 0) {
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return june_offset + ",1," + HEMISPHERE_SOUTH;
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}
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return january_offset + ",0";
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},
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/**
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* Uses get_timezone_info() to formulate a key to use in the olson.timezones dictionary.
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*
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* Returns a primitive object on the format:
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* {'timezone': TimeZone, 'key' : 'the key used to find the TimeZone object'}
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*
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* @returns Object
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*/
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determine = function () {
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var key = lookup_key();
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return new jstz.TimeZone(jstz.olson.timezones[key]);
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},
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/**
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* This object contains information on when daylight savings starts for
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* different timezones.
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*
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* The list is short for a reason. Often we do not have to be very specific
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* to single out the correct timezone. But when we do, this list comes in
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* handy.
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*
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* Each value is a date denoting when daylight savings starts for that timezone.
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*/
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dst_start_for = function (tz_name) {
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var ru_pre_dst_change = new Date(2010, 6, 15, 1, 0, 0, 0), // In 2010 Russia had DST, this allows us to detect Russia :)
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dst_starts = {
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'America/Denver': new Date(2011, 2, 13, 3, 0, 0, 0),
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'America/Mazatlan': new Date(2011, 3, 3, 3, 0, 0, 0),
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'America/Chicago': new Date(2011, 2, 13, 3, 0, 0, 0),
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'America/Mexico_City': new Date(2011, 3, 3, 3, 0, 0, 0),
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'America/Asuncion': new Date(2012, 9, 7, 3, 0, 0, 0),
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'America/Santiago': new Date(2012, 9, 3, 3, 0, 0, 0),
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'America/Campo_Grande': new Date(2012, 9, 21, 5, 0, 0, 0),
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'America/Montevideo': new Date(2011, 9, 2, 3, 0, 0, 0),
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'America/Sao_Paulo': new Date(2011, 9, 16, 5, 0, 0, 0),
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'America/Los_Angeles': new Date(2011, 2, 13, 8, 0, 0, 0),
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'America/Santa_Isabel': new Date(2011, 3, 5, 8, 0, 0, 0),
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'America/Havana': new Date(2012, 2, 10, 2, 0, 0, 0),
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'America/New_York': new Date(2012, 2, 10, 7, 0, 0, 0),
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'Europe/Helsinki': new Date(2013, 2, 31, 5, 0, 0, 0),
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'Pacific/Auckland': new Date(2011, 8, 26, 7, 0, 0, 0),
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'America/Halifax': new Date(2011, 2, 13, 6, 0, 0, 0),
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'America/Goose_Bay': new Date(2011, 2, 13, 2, 1, 0, 0),
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'America/Miquelon': new Date(2011, 2, 13, 5, 0, 0, 0),
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'America/Godthab': new Date(2011, 2, 27, 1, 0, 0, 0),
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'Europe/Moscow': ru_pre_dst_change,
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'Asia/Amman': new Date(2013, 2, 29, 1, 0, 0, 0),
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'Asia/Beirut': new Date(2013, 2, 31, 2, 0, 0, 0),
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'Asia/Damascus': new Date(2013, 3, 6, 2, 0, 0, 0),
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'Asia/Jerusalem': new Date(2013, 2, 29, 5, 0, 0, 0),
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'Asia/Yekaterinburg': ru_pre_dst_change,
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'Asia/Omsk': ru_pre_dst_change,
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'Asia/Krasnoyarsk': ru_pre_dst_change,
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'Asia/Irkutsk': ru_pre_dst_change,
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'Asia/Yakutsk': ru_pre_dst_change,
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'Asia/Vladivostok': ru_pre_dst_change,
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'Asia/Baku': new Date(2013, 2, 31, 4, 0, 0),
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'Asia/Yerevan': new Date(2013, 2, 31, 3, 0, 0),
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'Asia/Kamchatka': ru_pre_dst_change,
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'Asia/Gaza': new Date(2010, 2, 27, 4, 0, 0),
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'Africa/Cairo': new Date(2010, 4, 1, 3, 0, 0),
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'Europe/Minsk': ru_pre_dst_change,
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'Pacific/Apia': new Date(2010, 10, 1, 1, 0, 0, 0),
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'Pacific/Fiji': new Date(2010, 11, 1, 0, 0, 0),
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'Australia/Perth': new Date(2008, 10, 1, 1, 0, 0, 0)
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};
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return dst_starts[tz_name];
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};
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return {
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determine: determine,
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date_is_dst: date_is_dst,
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dst_start_for: dst_start_for
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};
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}());
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/**
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* Simple object to perform ambiguity check and to return name of time zone.
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*/
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jstz.TimeZone = function (tz_name) {
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'use strict';
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/**
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* The keys in this object are timezones that we know may be ambiguous after
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* a preliminary scan through the olson_tz object.
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*
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* The array of timezones to compare must be in the order that daylight savings
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* starts for the regions.
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*/
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var AMBIGUITIES = {
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'America/Denver': ['America/Denver', 'America/Mazatlan'],
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'America/Chicago': ['America/Chicago', 'America/Mexico_City'],
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'America/Santiago': ['America/Santiago', 'America/Asuncion', 'America/Campo_Grande'],
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'America/Montevideo': ['America/Montevideo', 'America/Sao_Paulo'],
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'Asia/Beirut': ['Asia/Amman', 'Asia/Jerusalem', 'Asia/Beirut', 'Europe/Helsinki','Asia/Damascus'],
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'Pacific/Auckland': ['Pacific/Auckland', 'Pacific/Fiji'],
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'America/Los_Angeles': ['America/Los_Angeles', 'America/Santa_Isabel'],
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'America/New_York': ['America/Havana', 'America/New_York'],
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'America/Halifax': ['America/Goose_Bay', 'America/Halifax'],
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'America/Godthab': ['America/Miquelon', 'America/Godthab'],
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'Asia/Dubai': ['Europe/Moscow'],
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'Asia/Dhaka': ['Asia/Yekaterinburg'],
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'Asia/Jakarta': ['Asia/Omsk'],
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'Asia/Shanghai': ['Asia/Krasnoyarsk', 'Australia/Perth'],
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'Asia/Tokyo': ['Asia/Irkutsk'],
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'Australia/Brisbane': ['Asia/Yakutsk'],
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'Pacific/Noumea': ['Asia/Vladivostok'],
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'Pacific/Tarawa': ['Asia/Kamchatka', 'Pacific/Fiji'],
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'Pacific/Tongatapu': ['Pacific/Apia'],
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'Asia/Baghdad': ['Europe/Minsk'],
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'Asia/Baku': ['Asia/Yerevan','Asia/Baku'],
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'Africa/Johannesburg': ['Asia/Gaza', 'Africa/Cairo']
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},
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timezone_name = tz_name,
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/**
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* Checks if a timezone has possible ambiguities. I.e timezones that are similar.
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*
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* For example, if the preliminary scan determines that we're in America/Denver.
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* We double check here that we're really there and not in America/Mazatlan.
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*
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* This is done by checking known dates for when daylight savings start for different
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* timezones during 2010 and 2011.
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*/
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ambiguity_check = function () {
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var ambiguity_list = AMBIGUITIES[timezone_name],
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length = ambiguity_list.length,
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i = 0,
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tz = ambiguity_list[0];
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for (; i < length; i += 1) {
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tz = ambiguity_list[i];
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if (jstz.date_is_dst(jstz.dst_start_for(tz))) {
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timezone_name = tz;
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return;
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}
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}
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},
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/**
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* Checks if it is possible that the timezone is ambiguous.
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*/
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is_ambiguous = function () {
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return typeof (AMBIGUITIES[timezone_name]) !== 'undefined';
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};
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if (is_ambiguous()) {
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ambiguity_check();
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}
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return {
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name: function () {
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return timezone_name;
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}
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};
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};
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jstz.olson = {};
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/*
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* The keys in this dictionary are comma separated as such:
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*
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* First the offset compared to UTC time in minutes.
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*
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* Then a flag which is 0 if the timezone does not take daylight savings into account and 1 if it
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* does.
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*
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* Thirdly an optional 's' signifies that the timezone is in the southern hemisphere,
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* only interesting for timezones with DST.
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*
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* The mapped arrays is used for constructing the jstz.TimeZone object from within
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* jstz.determine_timezone();
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*/
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jstz.olson.timezones = {
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'-720,0' : 'Pacific/Majuro',
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'-660,0' : 'Pacific/Pago_Pago',
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'-600,1' : 'America/Adak',
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'-600,0' : 'Pacific/Honolulu',
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'-570,0' : 'Pacific/Marquesas',
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'-540,0' : 'Pacific/Gambier',
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'-540,1' : 'America/Anchorage',
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'-480,1' : 'America/Los_Angeles',
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'-480,0' : 'Pacific/Pitcairn',
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'-420,0' : 'America/Phoenix',
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'-420,1' : 'America/Denver',
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'-360,0' : 'America/Guatemala',
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'-360,1' : 'America/Chicago',
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'-360,1,s' : 'Pacific/Easter',
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'-300,0' : 'America/Bogota',
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'-300,1' : 'America/New_York',
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'-270,0' : 'America/Caracas',
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'-240,1' : 'America/Halifax',
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'-240,0' : 'America/Santo_Domingo',
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'-240,1,s' : 'America/Santiago',
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'-210,1' : 'America/St_Johns',
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'-180,1' : 'America/Godthab',
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'-180,0' : 'America/Argentina/Buenos_Aires',
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'-180,1,s' : 'America/Montevideo',
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'-120,0' : 'America/Noronha',
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'-120,1' : 'America/Noronha',
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'-60,1' : 'Atlantic/Azores',
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'-60,0' : 'Atlantic/Cape_Verde',
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'0,0' : 'Etc/UTC',
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'0,1' : 'Europe/London',
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'60,1' : 'Europe/Berlin',
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'60,0' : 'Africa/Lagos',
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'60,1,s' : 'Africa/Windhoek',
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'120,1' : 'Asia/Beirut',
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'120,0' : 'Africa/Johannesburg',
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'180,0' : 'Asia/Baghdad',
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'180,1' : 'Europe/Moscow',
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'210,1' : 'Asia/Tehran',
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'240,0' : 'Asia/Dubai',
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'240,1' : 'Asia/Baku',
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'270,0' : 'Asia/Kabul',
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'300,1' : 'Asia/Yekaterinburg',
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'300,0' : 'Asia/Karachi',
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'330,0' : 'Asia/Kolkata',
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'345,0' : 'Asia/Kathmandu',
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'360,0' : 'Asia/Dhaka',
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'360,1' : 'Asia/Omsk',
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'390,0' : 'Asia/Rangoon',
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'420,1' : 'Asia/Krasnoyarsk',
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'420,0' : 'Asia/Jakarta',
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'480,0' : 'Asia/Shanghai',
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'480,1' : 'Asia/Irkutsk',
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'525,0' : 'Australia/Eucla',
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'525,1,s' : 'Australia/Eucla',
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'540,1' : 'Asia/Yakutsk',
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'540,0' : 'Asia/Tokyo',
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'570,0' : 'Australia/Darwin',
|
||
|
|
'570,1,s' : 'Australia/Adelaide',
|
||
|
|
'600,0' : 'Australia/Brisbane',
|
||
|
|
'600,1' : 'Asia/Vladivostok',
|
||
|
|
'600,1,s' : 'Australia/Sydney',
|
||
|
|
'630,1,s' : 'Australia/Lord_Howe',
|
||
|
|
'660,1' : 'Asia/Kamchatka',
|
||
|
|
'660,0' : 'Pacific/Noumea',
|
||
|
|
'690,0' : 'Pacific/Norfolk',
|
||
|
|
'720,1,s' : 'Pacific/Auckland',
|
||
|
|
'720,0' : 'Pacific/Tarawa',
|
||
|
|
'765,1,s' : 'Pacific/Chatham',
|
||
|
|
'780,0' : 'Pacific/Tongatapu',
|
||
|
|
'780,1,s' : 'Pacific/Apia',
|
||
|
|
'840,0' : 'Pacific/Kiritimati'
|
||
|
|
};
|
||
|
|
|
||
|
|
if (typeof exports !== 'undefined') {
|
||
|
|
exports.jstz = jstz;
|
||
|
|
} else {
|
||
|
|
root.jstz = jstz;
|
||
|
|
}
|
||
|
|
})(this);
|