<?php
declare(strict_types=1);

interface Formatter
{
    public const string MEDIA_TYPE = 'application/octet-stream';
    public function format(array $value): string;
}

final class JsonFormatter implements Formatter
{
    public const string MEDIA_TYPE = 'application/json';

    #[\Override]
    public function format(array $value): string
    {
        return json_encode($value, JSON_THROW_ON_ERROR);
    }
}

try {
    echo JsonFormatter::MEDIA_TYPE, PHP_EOL;
    echo (new JsonFormatter())->format(['enabled' => true]), PHP_EOL;
} catch (JsonException $error) {
    fwrite(STDERR, 'The value cannot be encoded as JSON.' . PHP_EOL);
    exit(1);
}