Function appendFile

lib/fs.js:2960–2983

* Asynchronously appends data to a file. * @param {string | Buffer | URL | number} path * @param {string | Buffer} data * @param {{ * encoding?: string | null; * mode?: number; * flag?: string; * flush?: boolean; * } | string} [options] * @param {(err?: Error) => any} callback *

(path, data, options, callback)

 * @returns {void}
 */
function appendFile(path, data, options, callback) {
  callback ||= options;
  validateFunction(callback, 'cb');

  options = getOptions(typeof options === 'function' ? null : options, {
    encoding: 'utf8', mode: 0o666, flag: 'a',
  });
  parseFileMode(options.mode, 'mode', 0o666);

  const h = vfsState.handlers;
  if (h !== null) {
    if (checkAborted(options.signal, callback)) return;
    if (vfsVoid(h.appendFile(path, data, options), callback)) return;
  }

  // Don't make changes directly on options object
  options = copyObject(options);

  // Force append behavior when using a supplied file descriptor
  if (!options.flag || isFd(path))
    options.flag = 'a';

  fs.writeFile(path, data, options, callback);
}

/**
 * Synchronously appends data to a file.