patternlab node - engine-twig-php extend/alter twig

alter-twig.php

<?php
/**
 * @param Twig_Environment $env - The Twig Environment - https://twig.symfony.com/api/1.x/Twig_Environment.html
 * @param $config - Config of `@basalt/twig-renderer`
 */
function addCustomExtension(\Twig_Environment &$env, $config) {

  $env->addExtension(new \Twig_Extension_Debug());

  /**
   * ADD TWIG EXTENDS FROM FOLDER
   */
  try {
    $functionsDir = __DIR__ . DIRECTORY_SEPARATOR . '_functions';
    $filtersDir = __DIR__ . DIRECTORY_SEPARATOR . '_filters';

    if ($handle = opendir($functionsDir)) {
      while (false !== ($fileName = readdir($handle))) {
        if ($fileName[0] != "_" && $fileName[0] != "." && substr_count(
            $fileName,
            '.function.php'
          )) {
          include($functionsDir . DIRECTORY_SEPARATOR . $fileName);
          // $function should be defined in the included file
          if (isset($function)) {
            $env->addFunction($function);
            unset($function);
          }
        }
      }
    }

    if ($handle = opendir($filtersDir)) {
      while (false !== ($fileName = readdir($handle))) {
        if ($fileName[0] != "_" && $fileName[0] != "." && substr_count($fileName, '.filter.php')) {
          include($filtersDir . DIRECTORY_SEPARATOR . $fileName);
          // $filter should be defined in the included file
          if (isset($filter)) {
            $env->addFilter($filter);
            unset($filter);
          }
        }
      }
    }
    // echo '--- ADDED TWIG EXT IN ' . (microtime(true) - $time) . 'ms' . PHP_EOL;
  } catch (Exception $e) {
    echo $e . PHP_EOL;
  }

}

patternlab-config.json

// patternlab config for basalt/twig-renderer to include the alter-twig.php file

{
  ....
  "engines": {
    "twig": {
      "namespaces": [
        ....
      ],
      "alterTwigEnv": [
        {
          "file": "source/_twig/alter-twig.php",
          "functions": [
            "addCustomExtension"
          ]
        }
      ]
    }
  }
}

trans.filter.php

<?php
// put this file in the _filters folder next to alter-twig.php
// trans filter is context aware, so it will pick up "keys" from the patternlab data.json files too

$filter = new Twig_SimpleFilter(
  'trans',
  function ($context, $string) {
    if (array_key_exists($string, $context)) {
      return $context[$string];
    }

    return $string;
  },
  [
    'needs_context' => true,
  ]
);