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Asked:2022-02-09 11:33:29 +0000 UTC2022-02-09 11:33:29 +0000 UTC

NodeJS中如何实现自动跟踪目录（文件夹）中的内容变化？

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同事，我有这样的功能，

const getFiles = (dir, files_) => {
  files_ = files_ || [];
  let files = fs.readdirSync(dir);
  for (var i in files) {
    var name = dir + '/' + files[i];
    if (fs.statSync(name).isDirectory()) {
      getFiles(name, files_);
    } else {
      files_.push(name);
    }
  }
  return files_;
};

console.log(getFiles('./frontend/multimedia/image'));

这很好用，但是我如何告诉这个函数来观察文件夹内容的变化（删除或添加文件）？

唯一想到的就是跑getFiles('./frontend/multimedia/image') 进去setInterval()。

我知道这不是最好的方法...

那么如何不重启这个功能，而是在里面实现文件夹跟踪呢？

javascript

1 个回答

  1. Best Answer

    Nodejs具有跟踪文件或目录更改的标准工具。

    fs.watch（文件名[，选项][，监听器]）

    const fs = require('fs');

const w = fs.watch(
  process.cwd(),
  { recursive: true },
  (eventType, filename) => {
    console.log('listener', eventType, filename);
  }
);

w.on('change', (eventType, filename) => {
  console.log('[h] change', eventType, filename);
});
w.on('error', (err) => console.error('[h] error', err));
w.on('close', () => console.log('[h] close'));

    控制台输出：

    $ node src/fs-watch-1/index.js 
rename tmp
rename tmp/q
rename tmp/.#q2
rename tmp/q2
rename tmp/.#q2
rename tmp/q
rename tmp
rename tmp1

    它们可以使用，但回调只接收两种类型的事件eventType——“重命名”或“更改”。并非所有类型的操作系统都会收到修改后文件的名称。

    一般来说，要解决“监视删除或添加文件”的问题，该工具的选择性较低，您将不得不手动添加检查。

    我推荐使用chokidar包。有了它，任务就轻松解决了：

    const chokidar = require('chokidar');

const watcher = chokidar.watch(process.cwd(), {
  persistent: true
});
watcher.on('ready', () => {
  watcher.on('add', (path) => console.log(`File ${path} has been added`))
    .on('unlink', (path) => console.log(`File ${path} has been removed`))
    .on('addDir', (path) => console.log(`Directory ${path} has been added`))
    .on('unlinkDir', (path) => console.log(`Directory ${path} has been removed`));
});

    控制台输出：

    $ node src/fs-watch-1/chokidar.js 
File /Users/xxx/git/stackoverflow-practice/tmp/q3 has been removed
File /Users/xxx/git/stackoverflow-practice/tmp/q1 has been removed
File /Users/xxx/git/stackoverflow-practice/tmp/q2 has been removed
Directory /Users/xxx/git/stackoverflow-practice/tmp has been removed

Directory /Users/xxx/git/stackoverflow-practice/tmp has been added
File /Users/xxx/git/stackoverflow-practice/tmp/q has been added
    • 2

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