How to print a JSON-structure from User models hierarchy - ruby-on-rails

Question

I am building an Rails 5 app and in this app I got a User model. Each user can have exactly one manager (using the attribute manager_id).
I want to print a JSON-structure (using Rabl) that shows how the User models are related. Meaning I want to print out how is manager to each user.
User 1 (manager_id is null)
|
User 2 (manager_id is 1)
User 3 (manager_id is 1)
|
User 4 (manager_id is 3)
This is what I want the UI to look like (this is already working I just need the JSON-structure to support it).
These is how the finished structure must look like.
datasource =
'name': 'Peter Fettingview'
'title': 'CEO'
'children': [
{
'name': 'Mike Palmer'
'title': 'CIO'
}
{
'name': 'Maria Persson'
'title': 'CTO'
'children': [
{
'name': 'James Hatton'
'title': 'Customer success'
}
{
'name': 'Lars Andersson'
'title': 'Customer success'
}
]
}
{
'name': 'Jan Roslund'
'title': 'Economy'
}
{
'name': 'Annika Holm'
'title': 'Sales'
}
]
This is what I got right now
attributes :id, :fullname
node :children do |n|
n.children.map { |c| partial("admin/users/index", :object => c) }
end
This is the output
[{
"id": 1,
"fullname": "Peter Fettingview",
"children": [{
"id": 2,
"fullname": "Richard Pooler"
},
{
"id": 1,
"fullname": "Mike Palmer"
}
]
},
{
"id": 2,
"fullname": "Richard Pooler",
"children": [{
"id": 3,
"fullname": "Mike Palmer"
}]
},
{
"id": 3,
"fullname": "Mike Palmer",
"children": []
}
]
How can I print out such a JSON-tree using the User models?

Answer 1

I have had to use tree data structures (i.e. self-referential models) before. I would consider using the Ancestry gem. It allows you to do things like enumerate descendants and paths bath to the root, making traversing your data structure significantly easier.