code: function () {
      var tzGuess = moment.tz.guess() || 'UTC';
      setCustomerTimezone(tzGuess);
  
      // Add the guessed customer timezone to list if its unknwon
      var knownTimezone = $.grep(timezones, function (tz) {
        return tz.key === customerTimezone
      }).length > 0
      if (!knownTimezone) {
        var name = '(' + moment().tz(customerTimezone).format('Z') + ') ' + customerTimezone
        timezones.unshift({
          key: customerTimezone,
          name: name
        });
      }
    }
docs: Guess the timezone and set global variable