Function writeFileSync

lib/fs.js:2889–2945

* Synchronously writes data to the file. * @param {string | Buffer | URL | number} path * @param {string | Buffer | TypedArray | DataView} data * @param {{ * encoding?: string | null; * mode?: number; * flag?: string; * flush?: boolean; * } | string} [options] * @returns {void}

(path, data, options)

 * @returns {void}
 */
function writeFileSync(path, data, options) {
  options = getOptions(options, {
    encoding: 'utf8',
    mode: 0o666,
    flag: 'w',
    flush: false,
  });
  const flush = options.flush ?? false;
  validateBoolean(flush, 'options.flush');
  parseFileMode(options.mode, 'mode', 0o666);

  const h = vfsState.handlers;
  if (h !== null) {
    const result = h.writeFileSync(path, data, options);
    if (result !== undefined) return;
  }

  const flag = options.flag || 'w';

  // C++ fast path for string data and UTF8 encoding
  if (typeof data === 'string' && (options.encoding === 'utf8' || options.encoding === 'utf-8')) {
    if (!isInt32(path)) {
      path = getValidatedPath(path);
    }

    return binding.writeFileUtf8(
      path,
      data,
      stringToFlags(flag),
      parseFileMode(options.mode, 'mode', 0o666),
    );
  }

  if (!isArrayBufferView(data)) {
    validateStringAfterArrayBufferView(data, 'data');
    data = Buffer.from(data, options.encoding || 'utf8');
  }

  const isUserFd = isFd(path); // File descriptor ownership
  const fd = isUserFd ? path : fs.openSync(path, flag, options.mode);

  let offset = 0;
  let length = data.byteLength;
  try {
    while (length > 0) {
      const written = fs.writeSync(fd, data, offset, length);
      offset += written;
      length -= written;
    }

    if (flush) {
      fs.fsyncSync(fd);
    }
  } finally {
    if (!isUserFd) fs.closeSync(fd);
  }
}