Need help to link several objects to one another (main object) with some specificities

PearlLea 0
Viewed 51

Need help to link several objects to one another (main object) with some specificities.

Hello, I need help to make this rendering from a JSON file. I tried several filters, I never managed to make it work the way I wanted. (This is a simplified example of my JSON file)

Input JSON:

[  
  {
    "id": "AAKG",
    "data": "some data...",
    "main_id": "none"
  },
  {
    "id": "PMBL",
    "data": "some data...",
    "main_id": "none"
  },
  {
    "id": "ZDFG",
    "data": "some data...",
    "main_id": "PMBL"
  },
  {
    "id": "XHGF",
    "data": "some data...",
    "main_id": "PMBL"
  },
  {
    "id": "LOKJ",
    "data": "some data...",
    "main_id": "none"
  },
  {
    "id": "JQWC",
    "data": "some data...",
    "main_id": "none"
  },
  {
    "id": "QQSZ",
    "data": "some data...",
    "main_id": "none"
  },
  {
    "id": "JQWC",
    "data": "some data...",
    "main_id": "QQSZ"
  },
  {
    "id": "LLRE",
    "data": "some data...",
    "main_id": "none"
  }
]

Output (what i want):

[  
  {
    "id": "AAKG",
    "data": "some data...",
    "main_id": "none"
  },
  {
    "id": "PMBL",
    "data": "some data...",
    "main_id": "none"
    "details": [
            {
                "id": "ZDFG",
                "data": "some data...",
                "main_id": "PMBL"
            },
            {
                "id": "XHGF",
                "data": "some data...",
                "main_id": "PMBL"
            }
        ]
  },
  {
    "id": "LOKJ",
    "data": "some data...",
    "main_id": "none"
  },
  {
    "id": "JQWC",
    "data": "some data...",
    "main_id": "none"
  },
  {
    "id": "QQSZ",
    "data": "some data...",
    "main_id": "none"
    "details": [
            {
                "id": "JQWC",
                "data": "some data...",
                "main_id": "QQSZ"
            }
        ]
  },
  {

  },
  {
    "id": "LLRE",
    "data": "some data...",
    "main_id": "none"
  }
]

Explanations:

In my input I have only one array that covers all the objects in my file, I would like to link all the objects in an Array that have in the "main_id" key value a specific value other than "none" (with key "details"), to the object (which I call the parent object) containing that same value in the "id" key of the parent object.

As you can see in my output example, which I think is more explicit than my explanations. Of course my real input file contains many more objects but the structure remains the same as in my example. [object,object,object,....]

jq json
1 Answers

A simple reduce with an if expression builig up an indexed object may suffice. The final map converts the object back to an array.

reduce .[] as $i ({};
  if $i.main_id == "none" then .[$i.id] += $i
  else .[$i.main_id].details += [$i] end
) | map(.)

[
  {
    "id": "AAKG",
    "data": "some data...",
    "main_id": "none"
  },
  {
    "id": "PMBL",
    "data": "some data...",
    "main_id": "none",
    "details": [
      {
        "id": "ZDFG",
        "data": "some data...",
        "main_id": "PMBL"
      },
      {
        "id": "XHGF",
        "data": "some data...",
        "main_id": "PMBL"
      }
    ]
  },
  {
    "id": "LOKJ",
    "data": "some data...",
    "main_id": "none"
  },
  {
    "id": "JQWC",
    "data": "some data...",
    "main_id": "none"
  },
  {
    "id": "QQSZ",
    "data": "some data...",
    "main_id": "none",
    "details": [
      {
        "id": "JQWC",
        "data": "some data...",
        "main_id": "QQSZ"
      }
    ]
  },
  {
    "id": "LLRE",
    "data": "some data...",
    "main_id": "none"
  }
]

Demo

pmf0
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