user_provider_memory.js

var userCounter = 1;

UserProvider = function(){};

UserProvider.prototype.dummyData = [];

UserProvider.prototype.findAll = function(callback){
  callback(null, this.dummyData);
};

UserProvider.prototype.findById = function(id, callback) {
  var result = null;
  for(var i = 0; i < this.dummyData.length; i++) {
    if(this.dummyData[i]._id == id) {
      result = this.dummyData[i];
      break;
    }
  }
  callback(null, result);
};

UserProvider.prototype.save = function(users, callback){
  var user = null;

  if(typeof(users.length)=="undefined"){
    users = [users];
  }

  for(var i = 0; i < users.length; i++){
    user = users[i];
    user._id = userCounter++;
    user.created_at = new Date();

    if(user.properties === undefined){
      user.properties = [];
    }

    for(var j = 0; j < user.properties.length; j++){
      user.properties[j].created_at = new Date();
    }
    this.dummyData[this.dummyData.length] = user; 
  }
  callback(null, users);
};

new UserProvider().save([
  {name: 'Alan', properties: [{job: 'Developer'}, {language: 'Ruby'}]},
  {name: 'Peter'},
  {name: 'Maya'}
], function(error, users){});

exports.UserProvider = UserProvider;