Backbone.NestedAttributesModel

Add Rails-like nested attributes support for Backbone.Model.

Installation

Add this line to your application's Gemfile:

gem 'backbone-nested-attributes'

And then execute:

$ bundle

Or install it yourself as:

$ gem install backbone-nested-attributes

Then, add this line in your application.js:

//= require backbone-nested-attributes/all

Usage

Make your model extend from Backbone.NestedAttributesModel, instead of Backbone.Model and declare your relationships:

var Post = Backbone.NestedAttributesModel.extend({
  relations: [
    {
      type: 'one',
      key: 'author',
      relatedModel: function () { return Person }
    },
    {
      key:  'comments',
      relatedModel: function () { return Comment }
    }
  ]
})

var Comment = Backbone.NestedAttributesModel.extend({})
var Person = Backbone.NestedAttributesModel.extend({})

Now you can create your posts like this:

var post = new Post({
  id: 123,
  title: 'My Title',
  author: { id: 987, name: "Vicente Mundim" },
  comments: [
    {
      id: 765,
      body: "Nice writeup!"
    },
    {
      id: 766,
      body: "Keep it going!"
    }
  ]
})

post.get('author')   // returns a Person model
post.get('comments') // returns a Backbone.Collection of Comment models

When saving data, you can choose whether to send attributes as usual, or with nested attributes support by giving { nested: true } to save:

post.save({}, { nested: true })

This will send data to the server like this:

{
  id: 123,
  title: 'My Title',
  author_attributes: { id: 987, name: "Vicente Mundim" },
  comments_attributes: [
    {
      id: 765,
      body: "Nice writeup!"
    },
    {
      id: 766,
      body: "Keep it going!"
    }
  ]
}

It keeps track of deleted models in 1-N relations:

var comment = post.get('comments').at(0)
post.get('comments').remove(comment)

post.save({}, { nested: true })

Send this data to the server:

{
  id: 123,
  title: 'My Title',
  author_attributes: { id: 987, name: "Vicente Mundim" },
  comments_attributes: [
    {
      id: 765,
      body: "Nice writeup!",
      _destroy: true
    },
    {
      id: 766,
      body: "Keep it going!"
    }
  ]
}

You can whitelist attributes to serialize using serialize_keys

var Post = Backbone.NestedAttributesModel.extend({
  relations: [
    {
      key:  'comments',
      serialize_keys: ['author', 'content'],
      relatedModel: function () { return Comment }
    }
  ]
})

The name of the attribute set on a destroyed model can be changed using destroy_action

var Post = Backbone.NestedAttributesModel.extend({
  relations: [
    {
      key:  'comments',
      destroy_action: '_remove',
      relatedModel: function () { return Comment }
    }
  ]
})

This allow you to call another method on the model instead of destroy.

Backbone.UndoableModel

If you're using some bind plugin and you want to cancel changes that were made without reloading the page or hitting the backend you'll definitively want to take a look at Backbone.UndoableModel:

var Post = Backbone.UndoableModel.extend({
  relations: [ // UndoableModel is a NestedAttributesModel, so it can have relations
    {
      type: 'one',
      key: 'author',
      relatedModel: function () { return Person }
    },
    {
      key:  'comments',
      relatedModel: function () { return Comment }
    }
  ]
})

var Comment = Backbone.UndoableModel.extend({})
var Person = Backbone.UndoableModel.extend({})

var post = new Post({
  id: 123,
  title: 'My Title',
  author: { id: 987, name: "Vicente Mundim" },
  comments: [
    {
      id: 765,
      body: "Nice writeup!"
    },
    {
      id: 766,
      body: "Keep it going!"
    }
  ]
})

post.set({ title: 'My new title' })
post.get('author').set({ name: 'Jon Snow' })
post.get('comments').at(0).set({ body: 'Great post!' })

post.undo() // that's it, post is now reverted to its initial attributes, as well as its relations

post.get('title')                      // 'My Title'
post.get('author').get('name')         // 'Vicente Mundim'
post.get('comments').at(0).get('body') // "Nice writeup!"

More info

Check out the specs:

• Backbone.NestedAttributesModel
• Backbone.UndoableModel

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request