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。
  • 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，并且仅在受支持的平台上有效（请参见注意事项）。 默认值: 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'。
  • signal <AbortSignal> 用于指示监视器何时应停止的 <AbortSignal>。
• 返回: <AsyncIterator> 具有以下属性的对象：
  • eventType <string> 变更类型
  • filename <string> | <Buffer> 变更的文件的名称。

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

const { watch } = require('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;
  }
})();

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'。

fs.watch() 的所有注意事项也适用于 fsPromises.watch()。

• filename <string> | <Buffer> | <URL>
• options <string> | <Object>
  • persistent <boolean> Indicates whether the process should continue to run as long as files are being watched. Default: true.
  • 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> Specifies the character encoding to be used for the filename passed to the listener. Default: 'utf8'.
  • signal <AbortSignal> An <AbortSignal> used to signal when the watcher should stop.
• Returns: <AsyncIterator> of objects with the properties:
  • eventType <string> The type of change
  • filename <string> | <Buffer> The name of the file changed.

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

const { watch } = require('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;
  }
})();

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

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