Whitelist function for the backbone base model. This allows me to select which attributes i want to send to the server or something else

baseModelWithWhiteList.js

//Define the base model
var BaseModel = Backbone.Model.extend({
        toJSON: function(options) {
            options = options || {};
            var json;
            if(!!options.whiteList)
                json = _.pick(this.attributes, options.whiteList);
            else if(!!options.blackList)
                json = _.omit(this.attributes, options.blackList);
            else 
                json = _.clone(this.attributes);

            for(var attr in json) {
              if((json[attr] instanceof app.models.BaseModel) || (json[attr] instanceof app.collections.BaseCollection)) {
                json[attr] = json[attr].toJSON(options[attr]);
              }
            }
            return json;
        }
    });

//you can extend the base model to a Person model for example
var Person = BaseModel.extend(/*...*/);

/*Example of usage*/
var aPerson = new Person();

//populate the model...
//get the filtered json version
var jsonVersion = aPerson.toJSON({
  whiteList: ['countries', 'firstName', 'type', 'id'],
  countries: {
      city: {whiteList: ['id', 'cid', 'name']},
      people: {blackList: ['cid']}
   }
});