Function urlToFilename

lib/internal/modules/helpers.js:360–380

* Coerce a URL string to a filename. This is used by the ESM loader * to map ESM URLs to entries in the CJS module cache on a best-effort basis. * TODO(joyeecheung): this can be rather expensive, cache the result on the * ModuleWrap wherever we can. * @param {string|undefined} url URL to convert

(url)

 * @returns {string|undefined}
 */
function urlToFilename(url) {
  if (url && StringPrototypeStartsWith(url, 'file://')) {
    let urlObj;
    try {
      urlObj = new URL(url);
    } catch {
      // Not a proper URL, return as-is as the cache key.
      return url;
    }
    try {
      return fileURLToPath(urlObj);
    } catch {
      // This is generally only possible when the URL is provided by a custom loader.
      // Just use the path and ignore whether it's absolute or not as there's no such
      // requirement for CJS cache.
      return urlObj.pathname;
    }
  }
  // Not a file URL, return as-is.
  return url;
}

// Whether we have started executing any user-provided CJS code.
// This is set right before we call the wrapped CJS code (not after,