Need help with transforming by adding root fields to child array elements

[allensutton-lumen]

Hello,

I have a JSON response from an API call, like this (edited for brevity and obfuscation purposes):

{
    "thing_name": "whatever",
    "thing_uuid": "lkjsadhlkjsa",
    "thing_id": 333333333,
    "child_stuff": [
        {
            "name": "child thing 1",
            "group": "widget flippers",
            "sequence": 0,
            "is_included": true,
            "dependent_on": "widget manufacturers",
            "modifier": 0
        },
        {
            "name": "child thing 2",
            "group": "underwater basket weavers",
            "sequence": 0,
            "is_included": false,
            "dependent_on": "water purification team",
            "modifier": 0
        }
    ]
}

Due to some limitations with the application we're using, I need to sort of flatten this JSON (this is a third-party off the shelf application that only accepts a certain JSON format, but luckily the vendor implemented a JSLT solution to do so), so that it looks like this:

[ 
    { 
        "a" : b, 
        "c" : d 
    }, 
    {
       "w" : x,
        "y" : z
    } 
]

So, using the example from earlier, the expected output would be this:

[
        {
            "thing_name": "whatever",
            "thing_uuid": "lkjsadhlkjsa",
            "thing_id": 333333333,
            "name": "child thing 1",
            "group": "widget flippers",
            "sequence": 0,
            "is_included": true,
            "dependent_on": "widget manufacturers",
            "modifier": 0
        },
        {
            "thing_name": "whatever",
            "thing_uuid": "lkjsadhlkjsa",
            "thing_id": 333333333,
            "name": "child thing 2",
            "group": "underwater basket weavers",
            "sequence": 0,
            "is_included": false,
            "dependent_on": "water purification team",
            "modifier": 0
        }
]

I found a solution that works, but it's a bit clunky:

let thing_name = (.thing_name)
let thing_uuid = (.thing_uuid)
let thing_id = (.thing_id)

[ 
   for (.child_stuff) {
            "thing_name": $thing_name,
            "thing_uuid": $thing_uuid,
            "thing_id": $thing_id,
            "name": .name,
            "group": .group,
            "sequence": .sequence,
            "is_included": .is_included,
            "dependent_on": .dependent_on,
            "modifier": .modifier
       }
 ]

Is there a way to do this more programmatically without having to statically define fields? Ideally I'd be able to use a nested for loop to first loop through the "child_stuff" array and then for each array item, loop through the three root fields and insert those into each child array item. That way if the fields change, I don't have to keep updating them and it "just works". Something like this:

let rootObj = (.)
[
    for(.child_stuff)
    {
        .key : .value,
        for($rootObj)
        if (not(is-array(.key)))
        .key : .value
    }
]

I did find a StackOverflow question that seemed to indicate that you can't pull parent values into a child item and the parent items need to be defined with let statements, which is fine for my purposes. I was trying to do something like this but I can't get the syntax right:

let baseObj = {
    "thing_name" : (.thing_name),
    "thing_uuid" : (.thing_uuid),
    "thing_id" : (.thing_id)
}

[
    for (.child_stuff) 
        { 
            .key : .value, 
            [
                 for ($baseObj) 
                     .key : .value
            ]
        }
]

I tried looking in the documentation, but I don't see anything that specifically mentions this, and searching forums doesn't seem to have a generic enough example for me to understand. Any help would be greatly appreciated.

[jacekszymanski]

Perhaps this one:

let root_stuff = [ for (.) . if (not(is-array(.value)) and not(is-object(.value))) ]

[
  for (.child_stuff) {
    for ([array(.), $root_stuff] | flatten(.)) .key : .value
  }
]