Function findLongestRegisteredExtension

lib/internal/modules/cjs/loader.js:623–635

* Find the longest (possibly multi-dot) extension registered in `Module._extensions`. * @param {string} filename The filename to find the longest registered extension for. * @returns {string}

(filename)

 * @returns {string}
 */
function findLongestRegisteredExtension(filename) {
  const name = path.basename(filename);
  let currentExtension;
  let index;
  let startIndex = 0;
  while ((index = StringPrototypeIndexOf(name, '.', startIndex)) !== -1) {
    startIndex = index + 1;
    if (index === 0) { continue; } // Skip dotfiles like .gitignore
    currentExtension = StringPrototypeSlice(name, index);
    if (Module._extensions[currentExtension]) { return currentExtension; }
  }
  return '.js';
}

/**
 * Tries to get the absolute file path of the parent module.