fsPromises.watch(filename[, options])


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:

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().