ical.js-one.com/lib/ical/timezone_service.js

[](http://travis-ci.org/mozilla-comm/ical.js)

// singleton class to contain timezones.
// Right now its all manual registry in the
// future we may use this class to download timezone
// information or handle loading pre-expanded timezones.
ICAL.TimezoneService = (function() {
  var zones;

  // Using var rather then return so we don't need to name the functions twice.
  // TimezoneService#get will appear in profiler, etc...
  var TimezoneService = {
    reset: function() {
      zones = Object.create(null);
      var utc = ICAL.Timezone.utcTimezone;

      zones.Z = utc;
      zones.UTC = utc;
      zones.GMT = utc;
    },

    /**
     * Checks if timezone id has been registered.
     *
     * @param {String} tzid (e.g. America/Los_Angeles).
     * @return {Boolean} false when not present.
     */
    has: function(tzid) {
      return !!zones[tzid];
    },

    /**
     * Returns a timezone by its tzid if present.
     *
     * @param {String} tzid name of timezone (e.g. America/Los_Angeles).
     * @return {ICAL.Timezone|Null} zone or null.
     */
    get: function(tzid) {
      return zones[tzid];
    },

    /**
     * Registers a timezone object or component.
     *
     * @param {String} [name] optional uses timezone.tzid by default.
     * @param {ICAL.Component|ICAL.Timezone} zone initialized zone or vtimezone.
     */
    register: function(name, timezone) {
      if (name instanceof ICAL.Component) {
        if (name.name === 'vtimezone') {
          timezone = new ICAL.Timezone(name);
          name = timezone.tzid;
        }
      }

      if (timezone instanceof ICAL.Timezone) {
        zones[name] = timezone;
      } else {
        throw new TypeError('timezone must be ICAL.Timezone or ICAL.Component');
      }
    },

    /**
     * Removes a timezone by its tzid from the list.
     *
     * @param {String} tzid (e.g. America/Los_Angeles).
     */
    remove: function(tzid) {
      return (delete zones[tzid]);
    }
  };

  // initialize defaults
  TimezoneService.reset();

  return TimezoneService;
}());