fs.appendFile(path, data[, options], callback)


异步地将数据追加到文件,如果该文件尚不存在,则创建该文件。 data 可以是字符串或 Buffer

fs.appendFile('message.txt', 'data to append', (err) => {
  if (err) throw err;
  console.log('The "data to append" was appended to file!');
});

如果 options 是字符串,则它指定编码:

fs.appendFile('message.txt', 'data to append', 'utf8', callback);

可以将 path 指定为已打开用于追加(使用 fs.open()fs.openSync())的数字文件描述符。 文件描述符不会自动关闭。

fs.open('message.txt', 'a', (err, fd) => {
  if (err) throw err;
  fs.appendFile(fd, 'data to append', 'utf8', (err) => {
    fs.close(fd, (err) => {
      if (err) throw err;
    });
    if (err) throw err;
  });
});

Asynchronously append data to a file, creating the file if it does not yet exist. data can be a string or a Buffer.

fs.appendFile('message.txt', 'data to append', (err) => {
  if (err) throw err;
  console.log('The "data to append" was appended to file!');
});

If options is a string, then it specifies the encoding:

fs.appendFile('message.txt', 'data to append', 'utf8', callback);

The path may be specified as a numeric file descriptor that has been opened for appending (using fs.open() or fs.openSync()). The file descriptor will not be closed automatically.

fs.open('message.txt', 'a', (err, fd) => {
  if (err) throw err;
  fs.appendFile(fd, 'data to append', 'utf8', (err) => {
    fs.close(fd, (err) => {
      if (err) throw err;
    });
    if (err) throw err;
  });
});