Ember Data JSON-API hasMany: How? - ember-data

Question

I'm familiar with the old ember-data "sideloading" model, which would look like this:
```
{
authors:[
{id:1, name:"Ernest", type: 'author', books: [1,2]
],
books: [
{id:1, name: "For whom the bell tolls", type: 'book', author:1},
{id:2, name: "Farewell To Arms", type: 'book', author:1}
]
}
But the new JSON-API method is different.
For one thing, (and I like this), attributes are separated from the id and type information, preventing namespace collisions.
I don't yet understand how to do a hasMany relationship with the JSON-API format. Can anyone point me to a doc or article on how this is expected? The examples on the JSON-API page show individual relationships, but not hasMany.
If you could write the above example in the new format, you'd have answered my question.

Answer 1

I found the answer in The JSON-API spec.
Each model should have a relationships key, whose value is an object with a key for each named relationship, which also has a data key that can be either a single object or an array for a hasMany relationship.
By providing an included key as top-level member, I can lazy load the entities.
In this case, the above example would be:
{
"data": [
{
"id": 1,
"type": "author",
"attributes": {
"name": "Ernest"
},
"relationships": {
"books": {
"data": [
{
"id": "1",
"type": "book"
},
{
"id": "2",
"type": "book"
}
]
}
}
}
],
"included": [
{
"id": 1,
"type": "book",
"attributes": {
"name": "For Whom the Bell Tolls"
},
"relationships": {
"author": {
"data": {
"id": 1,
"type": "author"
}
}
}
},
{
"id": 2,
"type": "book",
"attributes": {
"name": "Farewell to Arms"
},
"relationships": {
"author": {
"data": {
"id": 1,
"type": "author"
}
}
}
}
]
}

Answer 2

FYI: If you want to fetch a hashMany relationship at a later time, you have two other options.
1. Use a Related Resource Link:
As soon as the hashMany relationship is needed, Ember Data will call the backend with related link to fetch all the relations.
{
"data": [{
...,
"relationships": {
"books": {
"links" {
"related": "http://example.com/books"
}
}
}
}]
}
2. Use find-ids
As soon as the hashMany relationship is needed, Ember Data will call the backend with an url to fetch given ids. In this example it would be http://example.com/books?ids=1&ids=2
{
"data": [{
...,
"relationships": {
"books": {
"books": {
"data" [{
"id": "1",
"type": "book"
}, {
"id": "2",
"type": "book"
}]
}
}
}
}]
}