如何使用fs.readdir访问同一目录下多个文件夹中的多个文件？

const fs = require('fs');

const mainDirectory = '/path/to/main/directory';

fs.readdir(mainDirectory, (err, folders) => {
  if (err) {
    console.error('Error reading directory:', err);
    return;
  }

  folders.forEach(folder => {
    const folderPath = mainDirectory + '/' + folder;
    
    fs.readdir(folderPath, (err, files) => {
      if (err) {
        console.error('Error reading folder:', folder, err);
        return;
      }
      
      files.forEach(file => {
        const filePath = folderPath + '/' + file;

        // 进行文件操作，例如读取文件内容
        fs.readFile(filePath, 'utf8', (err, data) => {
          if (err) {
            console.error('Error reading file:', file, err);
            return;
          }

          // 处理文件内容
          console.log('File:', file);
          console.log('Content:', data);
        });
      });
    });
  });
});