The TypeInfo Component

The TypeInfo component extracts type information from PHP elements like properties, arguments and return types.

This component provides:

A powerful Type definition that can handle unions, intersections, and generics (and can be extended to support more types in the future);
A way to get types from PHP elements such as properties, method arguments, return types, and raw strings.

Installation

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        $ composer require symfony/type-info
    

Note

If you install this component outside of a Symfony application, you must require the vendor/autoload.php file in your code to enable the class autoloading mechanism provided by Composer. Read this article for more details.

Usage

This component gives you a Type object that represents the PHP type of anything you built or asked to resolve.

There are two ways to use this component. First one is to create a type manually thanks to the Type static methods as following:

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        use Symfony\Component\TypeInfo\Type;

Type::int();
Type::nullable(Type::string());
Type::generic(Type::object(Collection::class), Type::int());
Type::list(Type::bool());
Type::intersection(Type::object(\Stringable::class), Type::object(\Iterator::class));

// Many others are available and can be
// found in Symfony\Component\TypeInfo\TypeFactoryTrait
    

The second way of using the component is to use TypeInfo to resolve a type based on reflection or a simple string:

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        use Symfony\Component\TypeInfo\Type;
use Symfony\Component\TypeInfo\TypeResolver\TypeResolver;

// Instantiate a new resolver
$typeResolver = TypeResolver::create();

// Then resolve types for any subject
$typeResolver->resolve(new \ReflectionProperty(Dummy::class, 'id')); // returns an "int" Type instance
$typeResolver->resolve('bool'); // returns a "bool" Type instance

// Types can be instantiated thanks to static factories
$type = Type::list(Type::nullable(Type::bool()));

// Type instances have several helper methods

// for collections, it returns the type of the item used as the key;
// in this example, the collection is a list, so it returns an "int" Type instance
$keyType = $type->getCollectionKeyType();

// you can chain the utility methods (e.g. to introspect the values of the collection)
// the following code will return true
$isValueNullable = $type->getCollectionValueType()->isNullable();
    

Each of these calls will return you a Type instance that corresponds to the static method used. You can also resolve types from a string (as shown in the bool parameter of the previous example)

Note

To support raw string resolving, you need to install phpstan/phpdoc-parser package.

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.

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