{@code key} could be the calling country code and the full significant number of a * certain number, or it could be just a phone-number prefix. * For example, the full number 16502530000 (from the phone-number +1 650 253 0000) is a valid * input. Also, any of its prefixes, such as 16502, is also valid. * * @return string[] the list of corresponding time zones */ protected function lookupTimeZonesForNumberKey(string $key): array { // Lookup in the map data. The returned String may consist of several time zones, so it must be // split. $timezonesString = $this->phonePrefixMap->lookupKey($key); if ($timezonesString === null) { return []; } return $this->tokenizeRawOutputString($timezonesString); } /** * Split {@code timezonesString} into all the time zones that are part of it. * * @param $timezonesString string * @return string[] */ protected function tokenizeRawOutputString(string $timezonesString): array { return explode(static::RAW_STRING_TIMEZONES_SEPARATOR, $timezonesString); } /** * Returns the list of time zones {@code number}'s calling country code corresponds to. * * @param $number PhoneNumber the phone number to look up * @return string[] the list of corresponding time zones */ public function lookupCountryLevelTimeZonesForNumber(PhoneNumber $number): array { return $this->lookupTimeZonesForNumberKey((string) $number->getCountryCode()); } }