bun-types/docs/guides/read-file/watch.md

Type definitions and documentation for Bun, an incredibly fast JavaScript runtime

---
name: Watch a directory for changes
---

Bun implements the `node:fs` module, including the `fs.watch` function for listening for file system changes.

This code block listens for changes to files in the current directory. By default this operation is _shallow_, meaning that changes to files in subdirectories will not be detected.

```ts
import { watch } from "fs";

const watcher = watch(import.meta.dir, (event, filename) => {
  console.log(`Detected ${event} in ${filename}`);
});
```

---

To listen to changes in subdirectories, pass the `recursive: true` option to `fs.watch`.

```ts
import { watch } from "fs";

const watcher = watch(
  import.meta.dir,
  { recursive: true },
  (event, filename) => {
    console.log(`Detected ${event} in ${filename}`);
  },
);
```

---

Using the `node:fs/promises` module, you can listen for changes using `for await...of` instead of a callback.

```ts
import { watch } from "fs/promises";

const watcher = watch(import.meta.dir);
for await (const event of watcher) {
  console.log(`Detected ${event.eventType} in ${event.filename}`);
}
```

---

To stop listening for changes, call `watcher.close()`. It's common to do this when the process receives a `SIGINT` signal, such as when the user presses Ctrl-C.

```ts
import { watch } from "fs";

const watcher = watch(import.meta.dir, (event, filename) => {
  console.log(`Detected ${event} in ${filename}`);
});

process.on("SIGINT", () => {
  // close watcher when Ctrl-C is pressed
  console.log("Closing watcher...");
  watcher.close();

  process.exit(0);
});
```

---

Refer to [API > Binary data > Typed arrays](https://bun.sh/docs/api/binary-data#typedarray) for more information on working with `Uint8Array` and other binary data formats in Bun.