Bindings & Singletons

Binding Interfaces

Bind an interface to a concrete implementation. Every call to make(InterfaceClass::class) will resolve to the bound concrete:

$container->bind(LoggerInterface::class, FileLogger::class);

$logger = $container->make(LoggerInterface::class);

Singletons

Register a class as a singleton with a factory closure. The same instance is returned on every make() call. Use this for anything that needs primitive constructor arguments (like values from .env):

$container->singleton(Database::class, function (Container $container) {
    return new Database(
        host: $_ENV['DB_HOST'],
        port: (int) $_ENV['DB_PORT'],
        name: $_ENV['DB_DATABASE'],
    );
});

$db1 = $container->make(Database::class);
$db2 = $container->make(Database::class);

assert($db1 === $db2);

The factory receives the container instance, so you can resolve other dependencies inside it:

$container->singleton(UserRepository::class, function (Container $container) {
    return new UserRepository(
        db: $container->make(Database::class),
    );
});