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

• path <string> | <Buffer> | <URL> | <number> 文件名或文件描述符

  ¥path <string> | <Buffer> | <URL> | <number> filename or file descriptor

• data <string> | <Buffer>

• options <Object> | <string>

  • encoding <string> | <null> 默认值：'utf8'

    ¥encoding <string> | <null> Default: 'utf8'

  • mode <integer> 默认值：0o666

    ¥mode <integer> Default: 0o666

  • flag <string> 参见 支持文件系统 flags。默认值：'a'。

    ¥flag <string> See support of file system flags. Default: 'a'.

  • flush <boolean> 如果是 true，则在关闭基础文件描述符之前将其刷新。默认值：false。

    ¥flush <boolean> If true, the underlying file descriptor is flushed prior to closing it. Default: false.

• callback <Function>

  • err <Error>

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>。

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

mode 选项仅影响新创建的文件。有关详细信息，请参阅 fs.open()。

¥The mode option only affects the newly created file. See fs.open() for more details.

import { appendFile } from 'node:fs';

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

如果 options 是字符串，则它指定编码：

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

import { appendFile } from 'node:fs';

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

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

¥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.

import { open, close, appendFile } from 'node:fs';

function closeFd(fd) {
  close(fd, (err) => {
    if (err) throw err;
  });
}

open('message.txt', 'a', (err, fd) => {
  if (err) throw err;

  try {
    appendFile(fd, 'data to append', 'utf8', (err) => {
      closeFd(fd);
      if (err) throw err;
    });
  } catch (err) {
    closeFd(fd);
    throw err;
  }
}); 拷贝