fs.watch and fs.watchFile can be used to watch file changes. However, there are some problems with them. Thus, we can find a lot of wrappers of these functions. Here I recommend Chokidar written by Paul Miller.

Installation

Install Chokidar via Node.js package manager:

npm install chokidar

Usage

Chokidar is very simple to use. Here is an example:

chokidar = require 'chokidar'
watcher = chokidar.watch 'files', persistent: true

watcher
  .on 'add', (path) ->
    console.log(path, 'added')
  .on 'change', (path) ->
    console.log(path, 'changed')
  .on 'unlink', (path) ->
    console.log(path, 'removed')

add and change also receive meta info as second argument:

watcher.on 'change' (path, stats) ->
  console.log('File', path, 'changed size to', stats.size)

You can find the definition of stats from http://nodejs.org/api/fs.html#fs_class_fs_stats.