# fb-watchman

`fb-watchman` is a filesystem watcher that uses the [Watchman](https://facebook.github.io/watchman/) file watching service from Facebook.

Watchman provides file change notification services using very efficient recursive watches and also allows more advanced change matching and filesystem tree querying operations using [a powerful expression syntax](https://facebook.github.io/watchman/docs/file-query.html#expressions).

## Install

You should [install Watchman](https://facebook.github.io/watchman/docs/install.html) to make the most of this module.

Then simply:

```
$ npm install fb-watchman
```

## Key Concepts

* Watchman recursively watches directories.
* Each watched directory is called a `root`.
* You must initiate a `watch` on a `root` using the `watch-project` command prior to subscribing to changes
* Rather than separately watching many sibling directories, `watch-project` consolidates and re-uses existing watches relative to a project root (the location of your `.watchmanconfig` or source control repository root)
* change notifications are relative to the project root

## How do I use it?

[Read the NodeJS watchman documentation](https://facebook.github.io/watchman/docs/nodejs.html)