Ember Data Nested Resources Tree Structure - ember.js

Question

I have a slightly peculiar problem with loading my tree structure into Ember.
My models are:
book.js
- parts: DS.hasMany('part', {inverse: 'book', async: true})
part.js
- subparts: DS.hasMany('part', {inverse: 'parent_part', async: true}),
With the following API responses:
GET /api/books:
{
books: [
{id: 1, links: {parts: "/api/books/1/parts"}},
...
]
}
GET /api/books/1/parts:
{
parts: [
{
id: 1,
subparts: [10, 11]
},
{
id: 2,
subparts: []
}
]
}
The problem is in the tree nature of the parts: The book only has direct descendants id 1 and 2, but these have sub-parts on their own.
The structure as it is works but results in multiple sub-queries for each part that was not included in the /books/1/parts result. I want to avoid these queries, not only because of performance reasons but also because I will need additional query parameters which would get lost at this step... I know about coalesceFindRequests but it introduces new problems.
To rephrase the problem, Ember Data thinks that every part that is included in the /books/1/parts response should be added directly to the book:parts property. How can I still load all records of the parts tree at the same time?
I tried renaming the fields, but Ember Data assigns the records based on the model name, not the field name.
I fear that some creative adapter overriding will be necessary here. Any idea appreciated. The backend is completely under my control, so I could change things on that end, too.

Answer 1

You need to use a process called sideloading, which should work as you expect (I've had issues in the past with sideloading data). As mentioned in this issue, you want to split your parts into two separate arrays.
{
// These are the direct children
"parts": [{...}, {...}],
// These are the extra records
"_parts": [{...}, {...}]
}