Optional (like in Java Platform SE 8 but in PHP)

A container object which may or may not contain a non-null value. If a value is present, isPresent() will return true and get() will return the value.

Additional methods that depend on the presence or absence of a contained value are provided, such as orElse() (return a default value if value not present) and ifPresent() (execute a block of code if the value is present).

This is a value-based class; use of identity-sensitive operations (including reference equality (==), identity hash code, or synchronization) on instances of Optional may have unpredictable results and should be avoided.

-- Optional (Java Platform SE 8)

It is an easy way to make sure that everyone has to check if they have (not) received a null.

Examples

namespace PetrKnap\Optional;

/** @var Optional<string> $optionalString */
$optionalString = Optional::of('data');
if ($optionalString->isPresent()) {
    echo $optionalString->get();
}

OptionalResource::ofFalsable(tmpfile())->ifPresent(function ($tmpFile): void {
    fwrite($tmpFile, 'data');
    fclose($tmpFile);
});

Create and use your own typed optional

namespace PetrKnap\Optional;

class YourClass {}

/**
 * @extends OptionalObject<YourClass>
 */
class YourOptional extends OptionalObject {
    protected static function getInstanceOf(): string {
        return YourClass::class;
    }
}
TypedOptional::register(YourOptional::class); // optional recommended step

function your_strong_typed_function(YourOptional $input): YourOptional {
    return YourOptional::empty();
}

/**
 * @param Optional<YourClass> $input
 * @return Optional<YourClass>
 */
function your_weak_typed_function(Optional $input): Optional {
    return YourOptional::empty();
}

---

Run composer require petrknap/optional to install it. You can support this project via donation. The project is licensed under the terms of the LGPL-3.0-or-later.