Creating your own Markdown parser for Fluid templates in Flow / Neos applications

composer.json

{
  "require": {
      "typo3/neos": "*",
      "erusev/parsedown": "~1.6"
  }
}

MarkdownViewHelper.php

<?php
namespace Vendor\Name\ViewHelpers\Format;

use TYPO3\Flow\Annotations as Flow;
use TYPO3\Fluid\Core\ViewHelper\AbstractViewHelper;

/**
 * ViewHelper rendering the given string through parsedown
 * GitHub: https://github.com/erusev/parsedown
 */
class MarkdownViewHelper extends AbstractViewHelper
{
    /**
     * @var boolean
     */
    protected $escapeChildren = false;
    
    /**
     * @var boolean
     */
    protected $escapeOutput = false;

    /**
     * @param string $value The given markdown string
     * @return string Returns the rendered html string
     */
    public function render($value = null)
    {
        if ($value === null) {
            $value = $this->renderChildren();
        }

        $parsedown = new \Parsedown();
        return $parsedown->text($value);
    }
}

MarkdownViewhelperExample.html

<div>
  {yourMarkdownString -> vendor.name:format.markdown()}
</div>

Settings.yaml

TYPO3:
  Flow:
    object:
      excludeClasses:
        # disable reflection for non-flow packages
        # since Flow 3.0+ this is the default behaviour
        'erusev.parsedown': ['.*']