An Angular service that helps with Timezone related things.

TimezoneService.js

/**
 * Bower dependencies:
 * timezone-js
 * moment
 * moment-timezone
 * angular-moment
 * angular-tz-extensions
 *
 * index.html:
 * <script src="lib/timezone-js/src/date.js"></script>
 * <script src="http://cdnjs.cloudflare.com/ajax/libs/jstimezonedetect/1.0.4/jstz.js"></script>
 * <script src="lib/moment/min/moment-with-locales.min.js"></script>
 * <script src="lib/moment-timezone/builds/moment-timezone-with-data.min.js"></script>
 * <script src="lib/moment-timezone/moment-timezone-utils.js"></script>
 * <script src="lib/angular-moment/angular-moment.min.js"></script>
 * <script src="lib/angular-tz-extensions/lib/angular-tz-extensions.min.js"></script>
 */
angular.module('curdcollective.services', [
	'angularMoment', 'Timezones'
])

/**
 * TimezoneService
 * Helper for Timezone related things
 * @url https://github.com/chouseknecht/angular-tz-extensions
 * @url https://github.com/urish/angular-moment
 * @url http://momentjs.com/timezone/
 */
.service('TimezoneService', function(moment, $timezones, $filter, angularMomentConfig) {

	//Get a list of timezones (via moment-timezone)
	var timezones = [];

	var autoDetectedTimezone = $timezones.getLocal() || 'UTC';

	function pad(value) {
		return value < 10 ? '0' + value : value;
	}

	function setDefaults(timezone){
		if(!this.autoDetectedTimezone && !timezone){
			return 'You need to detect the timezone first.';
		}
		//Set the default timezone
		moment.tz.setDefault(this.autoDetectedTimezone);
		angularMomentConfig.timezone = this.autoDetectedTimezone;
	}

	return {

		//
		//Initializes the timezone methods and loads required variables
		//
		initTimezones: function(){
			this.timezones = [];
			angular.forEach(moment.tz.names(), function (zone, key) {
				this.push({
					name: zone,
					abbr: moment.tz(zone).zoneAbbr(),
					offset: moment.tz(zone).format('Z')
				});
			}, this.timezones);
		},
		
		getTimezoneOffset: function(tz){
			if(!tz){
				tz = this.autoDetectedTimezone;
			}
			var rightNow = new Date();
			var tzAlign = $timezones.align(rightNow, tz);
			return tzAlign.getTimezoneOffset();
		},

		getHours: function(tz){
			if(!tz){
				tz = this.autoDetectedTimezone;
			}
			var rightNow = new Date();
			var tzAlign = $timezones.align(rightNow, tz);
			return tzAlign.getHours();
		},

		getGMTOffset: function(tz){
			if(!tz){
				tz = this.autoDetectedTimezone;
			}
			var rightNow = new Date();
			var tzAlign = $timezones.align(rightNow, tz);
			return $filter('date')(tzAlign,'Z');
		},

		//See https://github.com/chouseknecht/angular-tz-extensions
		getLocale: function(tz){
			if(!tz){
				tz = this.autoDetectedTimezone;
			}
			return tz.locality;
		},

		//Handles setting the default timezone for the app.
		setDefaults: function(timezone){
			if(!this.autoDetectedTimezone && !timezone){
				return 'You need to detect the timezone first.';
			}
			//Set the default timezone
			moment.tz.setDefault(this.autoDetectedTimezone);
			angularMomentConfig.timezone = this.autoDetectedTimezone;
		},

		//Handles auto-detecting the user's timezone
		detect: function(){
			this.autoDetectedTimezone = $timezones.getLocal() || 'UTC';
			setDefaults(this.autoDetectedTimezone.name);
			return this.autoDetectedTimezone.name;
		},

		//Retrieves a list of all timezones known
		getTimezones: function(){
			return this.timezones;
		},

		//DEPRECATED
		/*createOffset: function(date) {
			var sign = (date.getTimezoneOffset() > 0) ? '-' : '+';
			var offset = Math.abs(date.getTimezoneOffset());
			var hours = pad(Math.floor(offset / 60));
			var minutes = pad(offset % 60);
			return sign + hours + ':' + minutes;
		}*/
	};
});

Any example? 👯