How to destroy the created objects in BackboneFactory and where are they stored?

Question

This is the source for BackboneFactory, a Backbone equivalent of FactoryGirl:

// Backbone Factory JS
// https://github.com/SupportBee/Backbone-Factory

(function(){
  window.BackboneFactory = {

    factories: {},
    sequences: {},

    define: function(factory_name, klass, defaults){

      // Check for arguments' sanity
      if(factory_name.match(/[^\w-_]+/)){
        throw "Factory name should not contain spaces or other funky characters";
      }

      if(defaults === undefined) defaults = function(){return {}};

      // The object creator
      this.factories[factory_name] = function(options){
        if(options === undefined) options = function(){return {}};
        arguments =  _.extend({}, {id: BackboneFactory.next("_" + factory_name + "_id")}, defaults.call(), options.call());
        return new klass(arguments);
      };

      // Lets define a sequence for id
      BackboneFactory.define_sequence("_"+ factory_name +"_id", function(n){
        return n
      });
    },

    create: function(factory_name, options){
      if(this.factories[factory_name] === undefined){
        throw "Factory with name " + factory_name + " does not exist";
      }
      return this.factories[factory_name].apply(null, [options]);        
    },

    define_sequence: function(sequence_name, callback){
      this.sequences[sequence_name] = {}
      this.sequences[sequence_name]['counter'] = 0;
      this.sequences[sequence_name]['callback'] = callback; 
    },

    next: function(sequence_name){
      if(this.sequences[sequence_name] === undefined){
        throw "Sequence with name " + sequence_name + " does not exist";
      }
      this.sequences[sequence_name]['counter'] += 1;
      return this.sequences[sequence_name]['callback'].apply(null, [this.sequences[sequence_name]['counter']]); //= callback; 
    }
  }
})();

So it looks like after some complicated logic, the create method will create a new object of a model that we define in backbone. If we have a User model, Backbone.create(User) will create a new user object.

Where are these objects stored?
Do they share the same database as production?
If it's in memory, are they garbage collected eventually?

In short, I'm concerned about what happens to these objects when running the test suite.

I see you've asked other questions since this one. Do you have any concerns with my answer you want me to address? — Emile Bergeron, Dec 11 '16 at 02:27

score 1 · Accepted Answer · edited May 23 '17 at 12:13

If we have a User model... Backbone.create(User) will create a new user object.

It's BackboneFactory.create('user') which works only if you have previously defined a factory for User using BackboneFactory.define('user', User);.

Where are these objects stored?

In the following properties of the global BackboneFactory object:

factories: {},
sequences: {},

Do they share the same database as production?

That's irrelevant as the factory only returns a model instance from a Model class that you have defined already.

Say you have this model:

var User = Backbone.Model.extend({
    urlRoot: "api/user",
    defaults: {
        name: "Foo",
        randomNumber: 4
    }
});

Instantiating with the factory:

BackboneFactory.define('user', User);
// somewhere later
var instance = BackboneFactory.create('user', { name: "bar" });

is the same as instantiating manually.

var instance = new User({ name: "bar" });

If it's in memory, are they garbage collected eventually?

It looks like it doesn't provide a simple function for removing a factory, but it's not really useful, because you create factories to use them in your app.

You could manually delete the factory hash and/or the sequences:

BackboneFactory.factories = {};
BackboneFactory.sequences = {};

But I would not do that in a normal use-case unless a specific problem arises. For the test suite, maybe it's the easiest way to "reset" the BackboneFactory object.

That being said, I wouldn't use that library as-is. There are great ideas, but the code is missing a lot of improvements for such a simple lib. One big no-no is that it's a global by default and it's not possible to create different instances of BackboneFactory. It has the problems of the singleton pattern.

How to destroy the created objects in BackboneFactory and where are they stored?

1 Answers1