Useful HTML filters for Timber Twig (widows and markdown support)

twig-filters.php

<?php 

add_filter( 'timber/twig', 'add_to_twig' );

function add_to_twig( $twig ) {
  $twig->addFilter( new Timber\Twig_Filter( 'noWidows', 'twigNoWidow' ) );  
  return $twig;
}

function twigNoWidow($text = "", $numberOfWords = 1, $outputRaw = true ) {
  $tags = "a|span|i|b|em|strong|acronym|caps|sub|sup|abbr|big|small|code|cite|tt";

  // Taken from https://github.com/davethegr8/cakephp-typogrify-helper/blob/master/views/helpers/typogrify.php
  $regex = "/([^\s])\s+(((<($tags)[^>]*>)*\s*[^\s<>]+)(<\/($tags)>)*[^\s<>]*\s*(<\/(p|h[1-6]|li)>|$))/i";
  $string = $text;

  for ($i = 0; $i < $numberOfWords; $i++) {
    $string = preg_replace($regex, '$1&nbsp;$2', $string);
  }
  return $string;
}

if ( function_exists('wpmarkdown_markdown_to_html') && function_exists('wpmarkdown_html_to_markdown') ) {
  add_filter( 'timber/twig', 'md_add_to_twig' );
  // Requires WP-Markdown 
  // Usage {{post.title|md2html}} {{post.description|html2md}}

  function md_add_to_twig( $twig ) {
      $twig->addFilter( new Timber\Twig_Filter( 'md2html', 'md2html' ) );
      $twig->addFilter( new Timber\Twig_Filter( 'html2md', 'html2md' ) );    
      return $twig;
  }

  function md2html($content) {
    return wpmarkdown_markdown_to_html($content);
  }
   
  function html2md($content) {
    return wpmarkdown_html_to_markdown($content);
  }
}