NodeJS directory watcher - basic monitor&move script

node_directory_watcher.js

function Watcher(watchDir, processedDir){
	this.watchDir = watchDir;
	this.processedDir = processedDir;
};

var events = require('events');

Watcher.prototype = new events.EventEmitter();

var fs = require('fs'),
	watchDir = './watch',
	processedDir = './done';

Watcher.prototype.watch = function(){
	var watcher = this;
	fs.readdir(this.watchDir, function(err, files){
		if(err) throw err;

		for(index in files){
			watcher.emit('process', files[index]);
		}
	});
};

Watcher.prototype.start = function(){
	var watcher = this;
	fs.watchFile(watchDir, function(){
		watcher.watch();
	});
};

var watcher = new Watcher("<directoryToWatch>", "<directoryToCopyTo>");

watcher.on('process', function(file){
	var watchFile = this.watchDir + "/" + file;
	var processedFile = this.processedDir + "/" + file.toLowerCase();

	fs.rename(watchFile, processedFile, function(err){
		if(err) throw err;
	});
});

watcher.start();