fsPromises.watch(filename[, options])

• filename <string> | <Buffer> | <URL>

• options <string> | <Object>

  • persistent <boolean> 指示只要正在监视文件，进程是否应继续运行。默认值：true。

    ¥persistent <boolean> Indicates whether the process should continue to run as long as files are being watched. Default: true.

  • recursive <boolean> 指示是应监视所有子目录，还是仅监视当前目录。这在指定目录时适用，并且仅适用于受支持的平台（参见 caveats）。默认值：false。

    ¥recursive <boolean> Indicates whether all subdirectories should be watched, or only the current directory. This applies when a directory is specified, and only on supported platforms (See caveats). Default: false.

  • encoding <string> 指定用于传给监听器的文件名的字符编码。默认值：'utf8'。

    ¥encoding <string> Specifies the character encoding to be used for the filename passed to the listener. Default: 'utf8'.

  • signal <AbortSignal> 用于指示监视器何时应停止的 <AbortSignal>。

    ¥signal <AbortSignal> An <AbortSignal> used to signal when the watcher should stop.

  • maxQueue <number> 指定在返回的 <AsyncIterator> 迭代之间排队的事件数。默认值：2048。

    ¥maxQueue <number> Specifies the number of events to queue between iterations of the <AsyncIterator> returned. Default: 2048.

  • overflow <string> 当排队的事件数量超过 maxQueue 允许的数量时，则为 'ignore' 或 'throw'。'ignore' 表示溢出事件将被丢弃并发出警告，而 'throw' 表示引发异常。默认值：'ignore'。

    ¥overflow <string> Either 'ignore' or 'throw' when there are more events to be queued than maxQueue allows. 'ignore' means overflow events are dropped and a warning is emitted, while 'throw' means to throw an exception. Default: 'ignore'.

• 返回：<AsyncIterator> 个具有以下属性的对象：

  ¥Returns: <AsyncIterator> of objects with the properties:

  • eventType <string> 变更类型

    ¥eventType <string> The type of change

  • filename <string> | <Buffer> | <null> 变更的文件的名称。

    ¥filename <string> | <Buffer> | <null> The name of the file changed.

返回异步迭代器，其监视 filename 上的更改，其中 filename 是文件或目录。

¥Returns an async iterator that watches for changes on filename, where filename is either a file or a directory.

const { watch } = require('node:fs/promises');

const ac = new AbortController();
const { signal } = ac;
setTimeout(() => ac.abort(), 10000);

(async () => {
  try {
    const watcher = watch(__filename, { signal });
    for await (const event of watcher)
      console.log(event);
  } catch (err) {
    if (err.name === 'AbortError')
      return;
    throw err;
  }
})(); 拷贝

在大多数平台上，只要目录中文件名出现或消失，就会触发 'rename'。

¥On most platforms, 'rename' is emitted whenever a filename appears or disappears in the directory.

fs.watch() 的所有 caveats 也适用于 fsPromises.watch()。

¥All the caveats for fs.watch() also apply to fsPromises.watch().