Ember.Model

Introduction

Ember Model (EM) is a simple and lightweight model library for Ember. It intentionally supports a limited feature set. The main goal is to provide primitives on top of $.ajax that are required by Ember.

EM is still very much a work in progress, but it's flexible enough to be used in apps today. It was extracted out of an Ember app. Please see the issues section for a list of bugs and planned features.

Getting Started with Ember Model

Download latest build of Ember Model

Need more help getting started? Join us in #ember-model on Freenode.

Features

• BYO$A (bring your own $.ajax)
• Relationships (hasMany/belongsTo)
• Focused on performance
• Automatic coalescing of multiple findById calls into a single findMany
• Fixtures
• Identity map (per class)
• Promises everywhere
• Customizable RESTAdapter

If you want more features than Ember Model provides, file an issue. Feature requests/contributions are welcome but the goal is to keep things simple and fast.

Example usage

var attr = Ember.attr, hasMany = Ember.hasMany;

// Model definitions
App.User = Ember.Model.extend({
  id: attr(),
  name: attr(),
  comments: hasMany("App.Comment", {key: 'comment_ids'})
});

App.User.url = "/users";
App.User.adapter = Ember.RESTAdapter.create();

App.Comment = Ember.Model.extend({
  id: attr(),
  text: attr()
});

App.Comment.url = "/comments";
App.Comment.adapter = Ember.RESTAdapter.create();

// create example

var newUser = App.User.create({name: "Erik"});
newUser.save(); // POST to /users.json

// hasMany example
var comments = newUser.get('comments');
comments.create({text: "hello!"});
comments.save(); // POST to /comments.json

// find & update example

var existingUser = App.User.find(1); // GET /users/1.json
existingUser.set('name', 'Kris');
existingUser.get('isDirty'); // => true
existingUser.save(); // PUT /users/1.json

Model API

Model.create - create a new record

Model#save - save or update record

Model#deleteRecord - delete a record

Model#load - load JSON into the record (typically used inside adapter definition)

Model#toJSON - serialize the record to JSON

Model.find() - find all records

Model.find(<String|Number>) - find by primary key (multiple calls within a single run loop can coalesce to a findMany)

Model.find(<object>) - find query - object gets passed directly to your adapter

Model.fetch() - find all records, returns a promise

Model.fetch(<String|Number>) - find by primary key (multiple calls within a single run loop can coalesce to a findMany), returns a promise

Model.fetch(<object>) - find query - object gets passed directly to your adapter, returns a promise

Model.load(<array>) - load an array of model data (typically used when preloading / sideloading data)

Adapter API

Ember.Adapter = Ember.Object.extend({
  find: function(record, id) {}, // find a single record

  findAll: function(klass, records) {}, // find all records

  findMany: function(klass, records, ids) {}, // find many records by primary key (batch find)

  findQuery: function(klass, records, params) {}, // find records using a query

  createRecord: function(record) {}, // create a new record on the server

  saveRecord: function(record) {}, // save an existing record on the server

  deleteRecord: function(record) {} // delete a record on the server
});

Attribute types

Attributes by default have no type and are not typecast from the representation provided in the JSON format.

Built in attribute types

Ember Model has built in Date and Number types. The Date type will deserialize strings into a javascript Date object, and will serialize dates into ISO 8601 format. The Number type will cast into a numeric type on serialization and deserialization.

App.Post = Ember.Model.extend({
  date: attr(Date),
  comment_count: attr(Number)
});

Custom attribute types

To provide custom attribute serialization and deserialization, create an object that has serialize and deserialize functions, and pass it into the attr helper:

var Time = {
  serialize: function(time) {
    return time.hour + ":" + time.min;
  },
  deserialize: function(string) {
    var array = string.split(":");
    return {
      hour: parseInt(array[0], 10),
      min: parseInt(array[1], 10)
    };
  }
};

var Post = Ember.Model.extend({
  time: attr(Time)
});

Relationships

Ember Model provides two types of relationships hasMany and belongsTo. Both types of relationships can either be embedded or referenced by ids.

Defining Relationships

Relationships are defined by using relationship computed property macros in place of Ember.attr. There are two macros available, one for each type of relationship.

Ember.belongsTo(type, options) - Provides access to a single related object.

Ember.hasMany(type, options) - Provides access to an array of related objects.

Both relationships take two arguments.

• type - Class of the related model or string representation (eg. App.Comment or 'App.Comment').

• options - An object with two properties, key which is required and embedded which is optional and defaults to false.

  • key - indicates what property of the JSON backing the model will be accessed to access the relationship
  • embedded - If true the related objects are expected to be present in the data backing the model. If false only the primaryKeys are present in the data backing the model. These keys will be used to load the correct model.

Relationship Examples

// Embedded Relationship Example

postJson = {
  id: 99,
  title: 'Post Title',
  body: 'Post Body',
  comments: [
    {
      id: 1,
      body: 'comment body one',
    },
    {
      id: 2,
      body: 'comment body two'
    }
  ]
};

App.Post = Ember.Model.extend({
  id: Ember.attr(),
  title: Ember.attr(),
  body: Ember.attr(),
  comments: Ember.hasMany('App.Comment', {key: 'comments', embedded: true})
});

App.Comment = Ember.Model.extend({
  id: Ember.attr(),
  body: Ember.attr()
});

// ID-based Relationship Example

postJson = {
  id: 99,
  title: 'Post Title',
  body: 'Post Body',
  comment_ids: [1, 2]
};

commentsJson = [
  {
    id: 1,
    body: 'Comment body one',
    post_id: 99
  },
  {
    id: 2,
    body: 'Coment body two',
    post_id: 99
  }
];

App.Post = Ember.Model.extend({
  id: Ember.attr(),
  title: Ember.attr(),
  body: Ember.attr()
  comments: Ember.hasMany('App.Comment', {key: 'comment_ids'})
});

App.Comment = Ember.Model.extend({
  id: Ember.attr(),
  body: Ember.attr(),
  post: Ember.belongsTo('App.Post', {key: 'post_id'})
})

Working with relationships

Working with a belongsTo relationship is just like working any other Ember.Model. An Ember.Model instance is returned when accessing a belongsTo relationship, so any Model methods can be used such as save() or reload().

comment.get('post').reload(); // Reloads the comments post

post.get('comments.lastObject').save(); // Saves the last comment associated to post

Accessing a hasMany relationship returns a HasManyArray or an EmbeddedHasManyArray which have useful methods for working with the collection of records. On any type of hasMany relationship you can call save() and all the dirty records in the collection will have their save() methods called. When working with an embedded hasMany relationship you can use the create(attrs) method to add a new record to the collection.

post.get('comments').save(); // Saves all dirty comments on post

// Below only works on embedded relationships
post.get('comments').create({body: 'New Comment Body'}); // Creates a new comment associated to post

Customizing

There are a few properties you can set on your class to customize how either Ember.Model or Ember.RESTAdapter work:

primaryKey

The property Ember Model uses for a per-record unique value (default: "id").

App.User = Ember.Model.extend({
  token: attr(),
  name: attr()
});
App.User.primaryKey = 'token';

GET /users/a4bc81f90.json
{"token": "a4bc81f90", "name": "Brian"}

rootKey

When RESTAdapter creates a record from data loaded from the server it will use the data from this property instead of the whole response body.

App.User = Ember.Model.extend({
  name: attr()
});
App.User.rootKey = 'user';

GET /users/1.json
{"user": {"id": 1, "name": "Brian"}}

collectionKey

When RESTAdapter creates multiple records from data loaded from the server it will use the data from this property instead of the whole response body.

App.User = Ember.Model.extend({
  name: attr()
});
App.User.collectionKey = 'users';

GET /users.json
{"users": [{"id": 1, "name": "Brian"}]}

camelizeKeys

If the server sends keys with underscores (ex: created_at), rather than camelized (ex: createdAt), setting this option to true makes Ember Model automatically camelize the keys.

App.User = Ember.Model.extend({
  firstName: attr()
});
App.User.camelizeKeys = true;

GET /users/1.json
{"id": 1, "first_name": "Brian"}

user.get('firstName') // => Brian

Customize Ajax Settings

When using RESTAdapter custom headers and ajax settings can be applied by extending RESTAdapter and defining ajaxSettings

App.CustomAdapter = Ember.RESTAdapter.extend({
  ajaxSettings: function(url, method) {
    return {
      url: url,
      type: method,
      headers: {
        "authentication": "xxx-yyy"
      },
      dataType: "json"
    };
  }
});

or it can be done at create time of the RESTAdapter

App.User.adapter = Ember.RESTAdapter.create({
  ajaxSettings: function(url, method) {
    return {
      url: url,
      type: method,
      headers: {
        "authentication": "xxx-yyy"
      },
      dataType: "json"
    };
  }
});

Building Ember Model

Ember Model uses node.js and grunt as a build system, These two libraries will need to be installed before building.

To build Ember Model, clone the repository, and run npm install to install build dependencies and grunt to build the library.

Unminified and minified builds of Ember Model will be placed in the dist directory.

How to Run Unit Tests

Setup

Ember Model uses node.js and grunt as a build system and test runner, and bower for dependency management.

If you have not used any of these tools before, you will need to run npm install -g bower and npm install -g grunt-cli to be able to use them.

To test Ember Model run npm install to install build dependencies, bower install to install the runtime dependencies and grunt test to execute the test suite headlessly via phantomjs.

If you prefer to run tests in a browser, you may start a development server using grunt develop. Tests are available at http://localhost:8000/tests

Who's using Ember Model?

• LiveNation
• Square
• Embercasts
• Digital Science
• Travis CI
• Bugzilla-Ember
• Embriak

Are you using Ember Model? Submit a pull request to add your project to this list!

Special Thanks

Yehuda Katz (@wycats), Tom Dale (@tomdale), Igor Terzic (@igorT), and company for their amazing work on Ember Data. I believe it's the most ambitious JS project today. The goal is someday everyone's JSON APIs will be conventional enough that Ember Data will be the best choice of data library for Ember. Until then, Ember Model will make it easy to get up and running quickly with Ember.