cakephp-tools/src/View/Widget/DatalistWidget.php

<?php
namespace Tools\View\Widget;

use Cake\Utility\Text;
use Cake\View\Form\ContextInterface;
use Cake\View\Widget\SelectBoxWidget;

/**
 * Datalist widget
 *
 * See /docs for usage.
 *
 * Additional config:
 * - keys: Use as true to use the keys of the select options instead of the values.
 * - input: Attributes for input element
 */
class DatalistWidget extends SelectBoxWidget
{
    /**
     * @param array $data
     * @param \Cake\View\Form\ContextInterface $context
     * @return string|null
     */
    public function render(array $data, ContextInterface $context)
    {
        $data += [
            'id' => null,
            'name' => '',
            'empty' => false,
            'escape' => true,
            'options' => [],
            'disabled' => null,
            'val' => null,
            'input' => [],
            'keys' => false,
            'templateVars' => [],
        ];

        $options = $this->_renderContent($data);
        if (!$data['keys']) {
            $options = str_replace(
                'value',
                'data-value',
                $options
            );
        }

        $name = $data['name'];
        $id = $data['id'] ?: Text::slug($name);
        $default = isset($data['val']) ? $data['val'] : null;

        $inputData = $data['input'] + [
            'id' => $id,
            'name' => $name,
            'autocomplete' => 'off',
        ];

        unset($data['name'], $data['options'], $data['empty'], $data['val'], $data['escape'], $data['keys'], $data['input'], $data['id']);
        if (isset($data['disabled']) && is_array($data['disabled'])) {
            unset($data['disabled']);
        }

        $inputData['value'] = $default;
        $inputAttrs = $this->_templates->formatAttributes($inputData);

        $datalistAttrs = $this->_templates->formatAttributes($data);
        return $this->_templates->format(
            'datalist',
            [
                'name' => $name,
                'inputAttrs' => $inputAttrs,
                'datalistAttrs' => $datalistAttrs,
                'content' => implode('', $options),
                'id' => $id,
            ]
        );
    }
}