DS.EmbeddedRecordsMixin#serializeHasMany()

Serializes hasMany relationships when it is configured as embedded objects.

This example of a post model has many comments:

Post = DS.Model.extend({
  title:    DS.attr('string'),
  body:     DS.attr('string'),
  comments: DS.hasMany('comment')
});

Comment = DS.Model.extend({
  body:     DS.attr('string'),
  post:     DS.belongsTo('post')
});

Use a custom (type) serializer for the post model to configure embedded comments

import DS from 'ember-data;

export default DS.RESTSerializer.extend(DS.EmbeddedRecordsMixin, {
  attrs: {
    comments: { embedded: 'always' }
  }
})

A payload with an attribute configured for embedded records can serialize the records together under the root attribute's payload:

{
  "post": {
    "id": "1"
    "title": "Rails is omakase",
    "body": "I want this for my ORM, I want that for my template language..."
    "comments": [{
      "id": "1",
      "body": "Rails is unagi"
    }, {
      "id": "2",
      "body": "Omakase O_o"
    }]
  }
}

The attrs options object can use more specific instruction for extracting and serializing. When serializing, an option to embed ids, ids-and-types or records can be set. When extracting the only option is records.

So { embedded: 'always' } is shorthand for: { serialize: 'records', deserialize: 'records' }

To embed the ids for a related object (using a hasMany relationship):

import DS from 'ember-data;

export default DS.RESTSerializer.extend(DS.EmbeddedRecordsMixin, {
  attrs: {
    comments: { serialize: 'ids', deserialize: 'records' }
  }
})

{
  "post": {
    "id": "1"
    "title": "Rails is omakase",
    "body": "I want this for my ORM, I want that for my template language..."
    "comments": ["1", "2"]
  }
}

To embed the relationship as a collection of objects with id and type keys, set ids-and-types for the related object.

This is particularly useful for polymorphic relationships where records don't share the same table and the id is not enough information.

By example having a user that has many pets:

User = DS.Model.extend({
  name:    DS.attr('string'),
  pets: DS.hasMany('pet', { polymorphic: true })
});

Pet = DS.Model.extend({
  name: DS.attr('string'),
});

Cat = Pet.extend({
  // ...
});

Parrot = Pet.extend({
  // ...
});

import DS from 'ember-data;

export default DS.RESTSerializer.extend(DS.EmbeddedRecordsMixin, {
  attrs: {
    pets: { serialize: 'ids-and-types', deserialize: 'records' }
  }
});

{
  "user": {
    "id": "1"
    "name": "Bertin Osborne",
    "pets": [
      { "id": "1", "type": "Cat" },
      { "id": "1", "type": "Parrot"}
    ]
  }
}