Function defaultLoadImpl

lib/internal/modules/cjs/loader.js:1237–1255

* Load the source code of a module based on format. * @param {string} filename Filename of the module. * @param {string|undefined|null} format Format of the module. * @returns {string|null}

(filename, format)

 * @returns {string|null}
 */
function defaultLoadImpl(filename, format) {
  switch (format) {
    case undefined:
    case null:
    case 'module':
    case 'commonjs':
    case 'json':
    case 'module-typescript':
    case 'commonjs-typescript':
    case 'typescript': {
      return fs.readFileSync(filename, 'utf8');
    }
    case 'builtin':
      return null;
    default:
      // URL is not necessarily necessary/available - convert it on the spot for errors.
      throw new ERR_UNKNOWN_MODULE_FORMAT(format, convertCJSFilenameToURL(filename));
  }
}

/**
 * Construct a last nextLoad() for load hooks invoked for the CJS loader.