TinyMCEWidget.php

<?php
namespace App\View\Widget;

use Cake\Core\Configure;
use Cake\I18n\I18n;
use Cake\View\Form\ContextInterface;
use Cake\View\Widget\BasicWidget;

/**
 * Input widget class for generating a textarea control.
 *
 * This class is intended as an internal implementation detail
 * of Cake\View\Helper\FormHelper and is not intended for direct use.
 */
class TinyMCEWidget extends BasicWidget
{
    /**
     * Render a text area form widget.
     *
     * Data supports the following keys:
     *
     * - `name` - Set the input name.
     * - `val` - A string of the option to mark as selected.
     * - `escape` - Set to false to disable HTML escaping.
     *
     * All other keys will be converted into HTML attributes.
     *
     * @param array $data The data to build a textarea with.
     * @param \Cake\View\Form\ContextInterface $context The current form context.
     * @return string HTML elements.
     */
    public function render(array $data, ContextInterface $context)
    {
        $access_key = Configure::read('data-get.biz.file_manager.access_key');
        $locale = I18n::locale();
        $mce =
            "<script>tinymce.init({" .
            "forced_root_block: false, relative_urls: false, mode : \"exact\", elements: \"" . $data['name'] . "\", theme: \"modern\", height : 300," .
            "plugins: [" .
            "\"advlist autolink link image lists charmap preview hr anchor pagebreak\"," .
            "\"searchreplace wordcount visualblocks visualchars insertdatetime media nonbreaking\"," .
            "\"table contextmenu directionality emoticons paste textcolor responsivefilemanager fullscreen\"]," .
            "toolbar1: \"undo redo | bold italic underline | alignleft aligncenter alignright alignjustify | bullist numlist outdent indent | styleselect\"," .
            "toolbar2: \"| responsivefilemanager | link unlink anchor | image media | forecolor backcolor  | fullscreen preview code \"," .
            "image_advtab: true," .
            "language: \"" . $locale . "\"," .
            "external_filemanager_path: \"/filemanager/\"," .
            "filemanager_access_key: \"" . $access_key . "\"," .
            "filemanager_title: \"Responsive Filemanager\"," .
            "external_plugins: {\"filemanager\": \"/filemanager/plugin.min.js\"}" .
            "});</script>";
        $data += [
            'val' => '',
            'name' => '',
            'escape' => true,
            'rows' => 5,
            'templateVars' => [],
        ];
        return $this->_templates->format('editor', [
            'name' => $data['name'],
            'value' => $data['escape'] ? h($data['val']) : $data['val'],
            'templateVars' => $data['templateVars'],
            'attrs' => $this->_templates->formatAttributes(
                $data,
                ['name', 'val']
            ),
            'mce' => $mce,
        ]);
    }
}

usage