Laravel/Eloquent normalize relations for JSON response? - php

Question

(Edited to add a better example with multiple characters with the same book and author)
Using Laravel 8, but this must be a generic enough problem I just don't know the name for or can't find. I've tried "normalizing eloquent JSON response" ad nauseum and nothing seems to be this specific issue.
I have some basic relations defined in Laravel, but I want to separate them out for a JSON response.
e.g.
Character belongsTo Book
Book belongsTo Author
So (ignore any syntax issues, it's quickly typed pseudo code)
$characters = Character::with('book', 'book.author')->get();
$characters->toJson();
Output:
[
{
"id": 1,
"book_id": 1,
"name": "Some character",
"book": [{
"id": 1,
"author_id": 1,
"name": "Some book",
"author": [{
"id": 1,
"name": "Some author"
}]
}]
},
{
"id": 2,
"book_id": 1,
"name": "A second character",
"book": [{
"id": 1,
"author_id": 1,
"name": "Some book",
"author": [{
"id": 1,
"name": "Some author"
}]
}]
}
]
But what I really want is this so I can feed it into a front end (React) simple ORM, but unnested and deduplicated (since the originally nested response could have the same book entry for multiple characters for example).
{
"characters": [{
"id": 1,
"book_id": 1,
"name": "Some character"
}, {
"id": 2,
"book_id": 1,
"name": "A second character"
}],
"books": [{
"id": 1,
"author_id": 1,
"name": "Some book"
}],
"authors": [{
"id": 1,
"name": "Some author"
}],
}