JQ, convert CSV (parent child format) to JSON, another questions

Question

This is a continue of another post: JQ, convert CSV (parent child format) to JSON

Hi, sorry to ask again. I tried to get the following format, without success. Really appreciate for some advice. I attach a picture to show how it looks like in a hierarchy view a picture to show in a hierarchy way, maybe it is easier. Hope it is possible ?

*** CSV file *****

id,parent_id,size
Subject,Null,1
analytics,Subject,1
cluster,analytics,1
AgglomerativeCluster,cluster,1
MergeEdge,cluster,2
animate,Subject,1
Easing,animate,3
interpolate,animate,1
ArrayInterpolator,interpolate,4
RectangleInterpolator,interpolate,5
Tween,animate,6

Here is the JSON file which I tried to achieve. If it is a parent (has a child under), only show ID. If it is a child, then show ID and Size.

**** JSON file ****

{
    "ID": "Subject",
    "children": [{
        "ID": "analytics",
        "children": [{
            "ID": "cluster",
            "children": [{
                "ID": "Aggl,ome,rativeCluster",
                "size": 1
            }, {
                "ID": "MergeEdge",
                "size": 2
            }]
        }]
    }, {
        "ID": "animate",
        "children": [{
            "ID": "Easing",
            "size": 3
        }, {
            "ID": "interpolate",
            "children": [{
                "ID": "ArrayInterpolator",
                "size": 4
            }, {
                "ID": "RectangleInterpolator",
                "size": 5
            }]
        }, {
            "ID": "Tween",
            "size": 6
            }]
        }]
}

Answer 1

To fill in the details about children recursively can most easily be accomplished using a recursive function -- here closure/2, which is written so as to be quite efficient.

def obj($headers):
  . as $in
  | reduce range(0; $headers|length) as $i ({}; 
      .[$headers[$i]] = $in[$i]);

# input:  either the id of an individual or 
#         an object representing an individual;
# output: the same individual but with .children and recursively
#         their children as an array of objects
def closure($dictionary; $children):
  def c: 
    if type == "string" then $dictionary[.] | c
    elif type=="object"
    then if has("children")
         then if (.children|length)>0 then .children = map(c) else . end
         elif $children[.id] then .children = ($children[.id] | map(c))
         else . end
    else . end;
  c;

split(",") as $headers
| [ inputs
    | split(",")
    | map_values(if . == "Null" then null else . end)
    | obj($headers) ]
| INDEX(.[]; .id) as $ids   # a dictionary mapping id => object
| (reduce .[] as $row ({};
      if $row.parent_id
      then .[$row.parent_id] += [$row.id]
      else . end ) ) as $children  # string => [ string ]
| map(closure($ids; $children) )
# tidy up:
| walk(if type=="object" 
       then if .children and (.children|length) > 0 
            then del(.size)
            else . end
       | del(.parent_id)
       else . end)