Nodejs function for copying a source to a destination file asynchronously

cpAsync.js

function cpAsync(srcPath,destPath,callback){

	var rs = fs.createReadStream(srcPath);
	var ws = fs.createWriteStream(destPath);

	rs.on('error', function(err) {
		console.log(err);
	});
	ws.on('error', function(err) {
		console.log(err);
	});
	if (callback){
		ws.on('finish',function(){
			callback(destPath);
		});
	}

	rs.pipe(ws);
}