simple DAO example for nodejs

CategoryRepository.js

var mongo = require('mongodb'),
    EventEmitter = require('events').EventEmitter;

function Connector(settings) {
  settings.port = settings.port || mongo.Connection.DEFAULT_PORT;
  this.settings = settings;
  this.server = new mongo.Server(settings.host, settings.port);
  this.db = new mongo.Db(settings.database, this.server, {native_parser: true});
}

Connector.prototype = new EventEmitter();

Connector.prototype.connect = function() {
  var that = this;
  this.db.open(function(err, db) {
    if (err) return that.emit('error', err);
    that.emit('ready', db);
  });
}



function CategoryRepository(db) {
  this.db = db;
}

CategoryRepository.prototype = new EventEmitter();

CategoryRepository.prototype.initialize = function() {
  var that = this;
  this.db.collection('categories', function(error, collection) {
    that.collection = collection;
    that.emit('ready', that);
  });
}

CategoryRepository.prototype.findAll = function(callback) {
  return this.db.collection('categories', onCollectionReady);
  function onCollectionReady(error, collection) {
    if (error) return callback(error);
    collection.find(onCursorReady);
  }
  function onCursorReady(error, cursor) {
    console.log('onCursorReady');    
    if (error) return callback(error, null);
    cursor.toArray(callback);
  }
}

function main() {
  var connector = new Connector({server:'localhost', database:'learntrack'});
  connector.on('ready', function() {
    var repo = new CategoryRepository(connector.db);
    repo.on('ready', onRepositoryReady);
    return connector.connect(onConnectionOpen);
    function onConnectionOpen(err, db) {
      console.log('connected');
      repo.initialize();
    }
    function onRepositoryReady(repo) {
      repo.findAll(onQueryResult);
    }
    function onQueryResult(err, items) {
      console.log('got results');
      console.dir(items);
      connector.db.close();
    }
  }
  connector.connect();
}

main();

What I get from this is that the preferred terminology in Node is "repository" and not "DAO"?

No, I don't know about general preference of nodejs community. I just like it more. It is taken from DDD and has slightly different meaning than DAO.

There is not a preference, it is agnostic to the language.
The above example is a DAO because is close to the storage layer, the repository usually use ORMs or DAO to prepare common queries.
Repository is a layer a little bit far of Storage.