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Backbone.SuperModel

Super as in fashion supermodel, not supernatural power. SuperModel extend Backbone.Model directly and override several of Backbone.Model methods to add support for nested attributes and many other features (coming soon!)

Install

Using NPM

npm install backbone.supermodel

Using bower

bower install backbone.supermodel

Using AMD script loader

  • Copy build/backbone.supermodel.amd.js to your project
  • Load it with require(['path/to/backbone.supermodel.amd'], function(SuperModel){}) and make sure that your have underscore and backbone stup correctly

Use it the old fashion way

  • Load build/backbone.supermodel.js in <head> or at the end of <body>
  • Make sure that you have underscore and backbone loaded before that

Nested attribute

It is quite often that nested attributes are used in an application. Considering this object structure

var wallet = {
  'money': {
    'amount': 4000,
    'currency': 'euro'
  },
  'name': 'Tan Nguyen'
}

With Backbone.Model we can have a model with an attribute wallet to store the above information, like this

var myStuff = new Backbone.Model();
myStuff.set('wallet', wallet);
myStuff.get('wallet').money.amount; // 4000

Although there is nothing wrong with this approach, it has several side-effects

  • By default an object is passed by reference and any changes to the object will affect all other variables that are storing that object. So if wallet.money.amount = 2000, then myStuff.get('wallet').money.amount will also be changed (unwillingly). It can sometimes cause weird behaviour in the application (trust me, I have been there before)

  • Nested attributes can not be listened to. In Backbone, a change to an attribute can be listened to by using change:[attribute] event. How about nested attributes? Nobody cares about nested attributes, that's why you can't listen to their changes, and they feel lonely, too

  • Get and set is not-so-backbone-style. So to change nested attribute value, one must do this myStuff.get('wallet').money.amount = 6000, it's totally ok to do this, it's just ugly and inconvenient. How about validation? there is no way we can validate it. How about previous value? forget it. We loose all the benefits of Backbone.Model when we use nested attribute that way

SuperModel to the rescue!!!

With SuperModel we will have a (maybe) better way to deal with nested attributes. Here is the list of some features

Support nested set and get

Each level of nested attribute is represented by a model or a collection depend on the value. It also supports relations which will be discussed later.

myStuff.get('wallet.money.amount');
myStuff.set('wallet.money.amount', 6000);
wallet.money.amout = 0; // this won't affect the data inside SuperModel
  • Array of number, string is reserved as it is
  • Array of object is turned into Collection
  • Empty Array is turned into Collection
  • Object is turned into Model
  • If the path points to a collection, the value is set as a key of the collection itself

Support nested change events

Although it is not recommended to have deep-nested models, SuperModel supports it anyway. There are several change events when using set. Note that, the deeper the path goes, the more events will be fired. Therefore, be careful when using deep nested paths.

// receive 6000 as the changed value
view.listenTo(myStuff, 'change:wallet.money.amount', view.doThing); 

// receive myStull.get('wallet.money') as the changed value
view.listenTo(myStuff, 'change:wallet.money', view.doThing);

// receive myStull.get('wallet') as the changed value
view.listenTo(myStuff, 'change:wallet', view.doThing);

// receive myStull.get('wallet.money') as the changed value
view.listenTo(myStull.get('wallet'), 'change:money', view.doThing);

// receive 6000 as the changed value
view.listenTo(myStull.get('wallet'), 'change:money.amount', view.doThing);

// receive 6000 as the changed value
view.listenTo(myStuff.get('wallet.money'), 'change:amount', view.doThing);

myStuff.set('wallet.money.amount', 6000);

toJSON

The standard toJSON is now able to return the correct nested format

myStuff.set('wallet.money.amount', 6000); // will fire 2 different events
var json = myStuff.toJSON(); 
// json = {
//   "wallet": {
//     "money": {
//       "amount": 6000
//     }
//   }
// }

By settings unsafeAttributes (an array or a function which returns an array), toJSON will exclude those attributes in the returned value

var MyModel = Backbone.SuperModel.extend({
  'unsafeAttributes': ['password']
});

var myModel = new MyModel({
  'username': 'supermodel',
  'password': 'secret'
});
myModel.toJSON(); // return {"username": "supermodel"}

Support relations

By defining relations, SuperModel can automatically initiate the corresponding class when it processes the attributes

var AnotherModel = SuperModel.extend({
  hello: function() {
    return this.get('hello');
  }
});

var Child = SuperModel.extend({
  name: function() {
    return this.get('name');
  }
});

var Children = Backbone.Collection.extend({
  model: Child,
  firstChild: function() {
    return this.at(0);
  }
});

var MyModel = SuperModel.extend({
  relations: {
    'another': AnotherModel,
    'children': Children
  }
});

var model = new MyModel({
  'another': {
    'hello': 'SuperModel'
  },
  'children': [
    {
      'name': 'First baby'
    },
    {
      'name': 'Second baby'
    }
  ]
});

model.get('another').hello(); // returns 'SuperModel'
model.get('children'); // returns Children object
model.get('children').firstChild(); // returns Child object
model.get('children').firstChild().name(); // returns 'First baby'

At the moment, the relation must be an instance of Backbone.Model or Backbone.Collection

Support backward reference

In some cases it might be useful that we can refer back to the upper level. For example, when rendering a list of posts, we might need to get the author information associated with each post. By setting name (can be a value or function), SuperModel will automatically build the back reference, if there is already an attribute with the same name, SuperModel will respect and skip it. The back reference is simply an attribute in the target model/collection in order to avoid circular reference when calling other methods such as toJSON

var Post = Backbone.SuperModel.extend({

});

var Posts = Backbone.Collection.extend({
  model: Post
});

var User = Backbone.SuperModel.extend({
  name: 'user',
  relations: {
    'posts': Posts
  }
});

var user = new User({
  'username': 'supermodel'
  'posts': [
    {
      'title': 'Post number 1'
    },
    {
      'title': 'Post number 2'
    }
  ]
});

user.get('posts').at(0).user.get('username'); // return 'supermodel'

TODOs

  • Support validation
  • Support as many Backbone.Model methods as possible
  • Support relations
  • Support back reference
  • Implement getRelation to replace the current way of accessing relations
  • Improve performance

Benchmarks

Running benchmark model_get [benchmarks/model_get.js]...
>> model_get x 48,381,420 ops/sec ±0.96% (93 runs sampled)

Running benchmark model_set [benchmarks/model_set.js]...
>> model_set x 300,337 ops/sec ±1.49% (96 runs sampled)

Running benchmark model_setget [benchmarks/model_setget.js]...
>> model_setget x 130,590 ops/sec ±1.49% (95 runs sampled)

Running benchmark supermodel_get [benchmarks/supermodel_get.js]...
>> supermodel_get x 4,487,165 ops/sec ±0.61% (98 runs sampled)

Running benchmark supermodel_nested_get [benchmarks/supermodel_nested_get.js]...
>> supermodel_nested_get x 1,999,848 ops/sec ±1.30% (95 runs sampled)

Running benchmark supermodel_nested_set [benchmarks/supermodel_nested_set.js]...
>> supermodel_nested_set x 45,619 ops/sec ±1.62% (95 runs sampled)

Running benchmark supermodel_set [benchmarks/supermodel_set.js]...
>> supermodel_set x 68,673 ops/sec ±1.12% (99 runs sampled)

Running benchmark supermodel_setget [benchmarks/supermodel_setget.js]...
>> supermodel_setget x 78,513 ops/sec ±2.04% (94 runs sampled)

It is obviously slower than the original Backbone.Model

Development

Gruntfile.js, package.json and bower.json are your friends

Contributors

https://github.com/laoshanlung/backbone.supermodel/graphs/contributors

License

MIT