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>

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

    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!');
    });

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

    import { appendFile } from 'node: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.

    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;
      }
    });