state.md

State

State is a feature that allows you to use enums state-driven. Think of state pattern. Out of the box it operates like a one-way traffic-light, from top to bottom. But you can make it as complex as you need it to be.

Usage

use Henzeb\Enumhancer\Concerns\State;

enum elevator
{
    use State;

    case Open;
    case Close;
    case Move;
    case Stop;
}

examples

Basic usage

elevator::Open->allowsTransition('Close'); // returns true
elevator::Open->allowsTransition(elevator::Move); // returns false

elevator::Open->transitionTo('Close'); // returns elevator::Close
elevator::Move->transitionTo(elevator::Close); // throws exception
elevator::Close->transitionTo('Open'); // throws exception

Complex Usage

use Henzeb\Enumhancer\Concerns\State;

enum elevator
{
    use State;

    case Open;
    case Close;
    case Move;
    case Stop;
    
    public static function transitions(): array
    {
        return [
            'open' => 'close',
            'close' => [
                'open',
                'move'
            ],
            'move' => 'stop',
            'stop' => 'open'
        ];
    }
}

elevator::Open->transitionTo(elevator::Close)
    ->transitionTo(elevator::Open)
    ->transitionTo(elevator::Close)
    ->transitionTo('Move')
    ->transitionTo(elevator::Stop)
    ->transitionTo('Open')
    ->transitionTo('Close'); //eventually returns elevator::Close

elevator::Move->transitionTo('Open'); //throws exception

The array returned by the transitions method can return an array containing the name or value as key, and the name, value or enum instance as value.

Note: You can only go one level deep.

Allowed transitions

When you want to present the transition options to your user, you can use allowedTransitions to get them (complex example):

elevator::Open->allowedTransitions(); // returns [elevator::Close]
elevator::Close->allowedTransitions(); // returns [elevator::Open, elevator::Move]
elevator::Move->allowedTransitions(); // returns [elevator::Stop]
elevator::Stop->allowedTransitions(); // returns [elevator::Open]

Note: when there are no transitions possible, allowedTranslations returns an empty array

Validation (laravel)

see State