mywebsite/node_modules/mongoose/examples/lean/lean.js

// import async to make control flow simplier
var async = require('async');

// import the rest of the normal stuff
var mongoose = require('../../lib');

require('./person.js')();

var Person = mongoose.model('Person');

// define some dummy data
var data = [
  { name : 'bill', age : 25, birthday : new Date().setFullYear((new
    Date().getFullYear() - 25)), gender : "Male",
    likes : ['movies', 'games', 'dogs']},
  { name : 'mary', age : 30, birthday : new Date().setFullYear((new
    Date().getFullYear() - 30)), gender : "Female",
    likes : ['movies', 'birds', 'cats']},
  { name : 'bob', age : 21, birthday : new Date().setFullYear((new
    Date().getFullYear() - 21)), gender : "Male",
    likes : ['tv', 'games', 'rabbits']},
  { name : 'lilly', age : 26, birthday : new Date().setFullYear((new
    Date().getFullYear() - 26)), gender : "Female",
    likes : ['books', 'cats', 'dogs']},
  { name : 'alucard', age : 1000, birthday : new Date().setFullYear((new
    Date().getFullYear() - 1000)), gender : "Male",
    likes : ['glasses', 'wine', 'the night']},
];


mongoose.connect('mongodb://localhost/persons', function (err) {
  if (err) throw err;

  // create all of the dummy people
  async.each(data, function (item, cb) {
    Person.create(item, cb);
  }, function (err) {
    
    // lean queries return just plain javascript objects, not
    // MongooseDocuments. This makes them good for high performance read
    // situations
    
    // when using .lean() the default is true, but you can explicitly set the
    // value by passing in a boolean value. IE. .lean(false)
    var q = Person.find({ age : { $lt : 1000 }}).sort('age').limit(2).lean();
    q.exec(function (err, results) {
      if (err) throw err;
      console.log("Are the results MongooseDocuments?: %s", results[0] instanceof mongoose.Document);

      console.log(results);
      cleanup();
    });
  });
});

function cleanup() {
  Person.remove(function() {
    mongoose.disconnect();
  });
}