README

Value objects

Base library for the usage of value objects.

Installation

You can install the package via composer:

composer require ohtyap/value-object

A generic interface

The main purpose of this repository is to provide generic interfaces for value objects, which is especially useful if you need a (reusable) way to transform data from the outside (your framework, ORM, etc.) to your domain layer (where you want to use value objects) and vice versa.

ValueObjectInterface

The ValueObjectInterface declares a class as value object. The only two necessary methods are equals() and value().

`equals()`

Value objects are equal due to the value of their properties. This means the following usually won't work when working with value objects:

(new ValueObject('value')) === (new ValueObject('value'));
(new ValueObject(new DateTime('2020-12-12'))) == (new ValueObject(new DateTime('2020-12-12')));
(new ValueObject('value')) == 'value';

equals() allows comparison based on the meaning of the value, not based on type or same instance of a class.

`value()`

This method should return the value as a type your application layer can understand. In most cases these are basic types like int or string, but also more complex types like arrayor \DateTime are possible.

TransformableInterface

To convert a variable to a value object you need to transform the variable via the TransformableInterface::transform().

$emailValueObj = YourEmailValueObject::transform('example@php.net');

Transformer

To avoid the direct usage of the TransformableInterfaceyou can use the transformer instead.

$transformer = new Transformer();
$emailValueObj = $transformer->transformValue(YourEmailValueObject::class, 'example@php.net');

Use add() to provide value object transformation. It is also possible to register a different transformable for a value object:

$transformer = new Transformer();
$transformer->addType(YourEmailValueObject::class, CustomEmailTransformable::class);

In case a (reusable) way of transforming a set of values (an array) to value objects, it is possible to add a schema:

$schema = new Schema('user');
$schema->addProperty('id', MyUuidValueObject::class);
$schema->addProperty('email', MyEmailValueObject::class);

$transformer = new Transformer();
$transformer->addSchema($schema);

$result = $transformer->transformBySchema('user', ['id' => 'bd24e386-754d-4a8d-8c82-9d9be47220e9', 'email' => 'example@php.net']);

Testing

composer run phpunit
composer run psalm
composer run phpstan
composer run infection

Changelog

Please see CHANGELOG for more information on what has changed recently.

Security

If you discover any security related issues, please email security@tpa.codes instead of using the issue tracker.

License

The MIT License (MIT). Please see License File for more information.

ohtyap / value-object

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