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