Using a single property to represent two values

[kohenkatz]

I have an API provided to me that represents US/Canada timezones as an object like this:

class Timezone
{
    public const VALID_ZONES = [
        'E', // Eastern
        'C', // Central
        'M', // Mountain
        'P', // Pacific
        'K', // Alaska
        'H', // Hawaii
        'A', // Atlantic
    ];

    public function __construct(
        public readonly string $zone,
        public readonly bool $dst,
    )
    {
        if (!in_array($zone, self::VALID_ZONES)) {
            throw new ValueError("Invalid zone ID '$zone'");
        }
    }
}

The problem is that in some parts of the API, the timezone information isn't actually a separate object, it is part of a larger object, like this:

{
    "account": "ABC123",
    "name": "My Location",
    "address": "...",
    "timezone": "E",
    "dst": "1"
}

(Yes, the value for daylight savings is a number stored as a string, not a boolean.

I would like to be able to use the existing Timezone class as part of the Account class that represents the data shown above, something like this:

class Account extends Data
{
    #[Computed]
    public string $dst;

    public function __construct(
        public readonly string $account,
        public readonly string $name,
        public readonly string $address,
        public readonly Timezone $timeZone,
    )
    {}
}

I read through the documentation, but I don't really see a good way to map two JSON values into a single property (for incoming data) and map that property back into two JSON values (for outgoing data).

Is there a way I can do this easily, or am I stuck keeping the Timezone data as two separate properties in the Account class?