ArrayType for CakePHP 3

bootstrap.php

<?php
use Cake\Database\Type;
Type::map('array', 'App\Database\Type\ArrayType');

src\Database\Type\ArrayType.php

<?php
/**
 * File src/Database/Type/ArrayType.php
 */
namespace App\Database\Type;

use Cake\Database\Driver;
use Cake\Database\Type;
use PDO;

class ArrayType extends Type
{

    public function toPHP($value, Driver $driver)
    {
        if ($value === null || empty($value)) {
            return [];
        }
        return explode(',', $value);
    }

    public function marshal($value)
    {
        if ($value === null || empty($value)) {
            return [];
        }
        return explode(',', $value);
    }

    public function toDatabase($value, Driver $driver)
    {
        if (is_array($value)) {
            $string = implode(",", $value);
            $string = preg_replace('/\s?,\s?/', ',', $string);
            return $string;
        }
        else {
            return $value;
        }
    }

    public function toStatement($value, Driver $driver)
    {
        if ($value === null) {
            return PDO::PARAM_NULL;
        }
        return PDO::PARAM_STR;
    }

}

src\Model\Table\ModelTable.php

<?php
namespace App\Model\Table;

use Cake\ORM\Table;
use Cake\Database\Schema\Table as Schema;

/**
 * Users Model
 */
class ModelTable extends Table
{
    protected function _initializeSchema(Schema $schema)
    {
        $schema->columnType('options', 'array');
        return $schema;
    }
}
?>

src\View\AppView.php

<?php
namespace App\View;

use Cake\View\View;

/**
 * Application View
 * Your application’s default view class
 * @link http://book.cakephp.org/3.0/en/views.html#the-app-view
 */
class AppView extends View
{
    public function initialize()
    {
        $this->loadHelper('Form',
            [
                'widgets' => [
                    'array' => [
                        'App\View\Widget\ArrayWidget'
                    ]
                ]
            ]
        );
    }
}

src\View\Widget\ArrayWidget.php

<?php
namespace App\View\Widget;

use Cake\View\Form\ContextInterface;
use Cake\View\Widget\WidgetInterface;

class ArrayWidget implements WidgetInterface
{

    protected $_templates;

    public function __construct($templates)
    {
        $this->_templates = $templates;
    }

    public function render(array $data, ContextInterface $context)
    {
        $data += [
            'value' => implode(',', $data['val'])
        ];
        return $this->_templates->format('input', [
            'name' => $data['name'],
            'type' => 'text',
            'attrs' => $this->_templates->formatAttributes(
                $data
            )
        ]);
    }

    public function secureFields(array $data)
    {
        return [$data['name']];
    }
}

view.ctp

<?php
echo $this->Form->input('options', [
    'type' => 'array',
]);
?>