Ember Data 2.5, a minor version release of Ember Data, is released. This release represents the work of over 31 direct contributors, and over 137 commits.
Ember Data 2.6 beta.1, the branch of Ember Data that will be released as stable in roughly six weeks, is also being released.
Changes in Ember Data 2.5
ds-finder-include
The ds-finder-include feature allows an include query parameter to
be specified using store.findRecord() and store.findAll() as
described in RFC 99. The
include parameter tells JSON-API servers which relationships to
sideload in a response, but it can also be used by custom adapters to
signal which relationships the backend can sideload to improve
performance.
Thanks to @HeroicEric for
implementing this feature.
// GET /articles/1?include=comments

var article = this.store.findRecord('article', 1, { include: 'comments' });

// GET /articles?include=comments

var article = this.store.findAll('article', { include: 'comments' });

ds-references
The ds-references feature implements the references API as described
in RFC 57. References is a
low level API to perform meta-operations on records, has-many
relationships and belongs-to relationships:

• get the current local data synchronously without triggering a fetch or producing a promise
• notify the store that a fetch for a given record has begun, and provide a promise for its result
• similarly, notify a record that a fetch for a given relationship has begun, and provide a promise for its result
• retrieve server-provided metadata about a record or relationship

Consider the following post model:
// app/models/post.js
import Model from 'ember-data/model';
import { belongsTo, hasMany } from 'ember-data/relationships';

export default Model.extend({
comments: hasMany(),
author: belongsTo()
});

The references API now allows the possibility to interact with the relationships:
var post = store.peekRecord('post', 1);

// check if the author is already loaded, without triggering a request
if (post.belongsTo('author').value() !== null) {
console.log(post.get("author.name"));
} else {
// get the id of the author without triggering a request
var authorId = post.belongsTo("author").id();

// load the author
post.belongsTo('author').load();
console.log(`Loading author with id ${authorId}`);
}

// reload the author
post.belongsTo('author').reload();

// get all ids without triggering a request
var commentIds = post.hasMany('comments').ids();

// check if there are comments, without triggering a request
if (post.hasMany('comments').value() !== null) {
var meta = post.hasMany('comments').meta();
console.log(`${commentIds.length} comments out of ${meta.total}`);
} else {
post.hasMany('comments').load();
}

// reload comments
post.hasMany('comments').reload();

Thanks to @pangratz for implementing
this feature.
ds-transform-pass-options
The ds-transform-pass-options feature allows for smarter transforms
by passing the options object from DS.attr([type], [options]) into
the transform.
Example
// app/models/post.js
export default DS.Model.extend({
title: DS.attr('string'),
markdown: DS.attr('markdown', {
markdown: {
gfm: false,
sanitize: true
}
})
});

// app/transforms/markdown.js
export default DS.Transform.extend({
serialize: function (deserialized, attributeMeta) {
return deserialized.raw;
},

deserialize: function (serialized, attributeMeta) {
var options = attributeMeta.options.markdown || {};

return marked(serialized, options);
}
});

Thanks to @pangratz for implementing
this feature and @knownasilya for
proposing the RFC.
Upcoming Features in Ember Data 2.6.beta-1

• ds-serialize-ids-and-types

Enables a new ids-and-type strategy (in addition to the already existing ids and records) for
serializing has many relationships using the DS.EmbeddedRecordsMixin that will include both
id and type of each model as an object.
For instance, if a user has many pets, which is a polymorphic relationship, the generated payload would be:
{
"user": {
"id": "1"
"name": "Bertin Osborne",
"pets": [
{ "id": "1", "type": "Cat" },
{ "id": "2", "type": "Parrot"}
]
}
}

This is particularly useful for polymorphic relationships not backed by STI when including the id of the records is not enough.
For more details on changes in the 2.6 beta, please review the
Ember Data 2.6.0-beta.1 CHANGELOG.