snippet to load composer autoload

vendor_autoload.php

// https://getcomposer.org/doc/articles/vendor-binaries.md#finding-the-composer-autoloader-from-a-binary
if (isset($GLOBALS['_composer_autoload_path'])) {
  // As of Composer 2.2...
  $_composer_autoload_path = $GLOBALS['_composer_autoload_path'];
}
else {
  // < Composer 2.2
  $ds = DIRECTORY_SEPARATOR;
  foreach ([
             __DIR__ . $ds . '..' . $ds . '..' . $ds . 'autoload.php',
             __DIR__ . $ds . '..' . $ds . 'vendor' . $ds . 'autoload.php',
             __DIR__ . $ds . 'vendor' . $ds . 'autoload.php',
           ] as $_composer_autoload_path) {
    if (file_exists($_composer_autoload_path)) {
      break;
    }
  }
}
$class_loader = require_once $_composer_autoload_path;