Jolt Transform complex json to a flat json

Question

I am looking to Jolt Transform a complex json into below desired json.

Input JSON:

{
  "Rating": 1,
  "SecondaryRatings": [
    {
      "Design": 4,
      "Price": 2,
      "RatingDimension3": 1,
      "Arr1": [
        {
          "Val1": 34
        },
        {
          "Val2": 45
        }
      ]
    },
    {
      "Design": 44,
      "Price": 23,
      "RatingDimension3": 12,
      "Arr1": [
        {
          "Val1": 56
        },
        {
          "Val2": 22
        }
      ]
    }
  ]
}

Desired Output

[
  {
    "Design": 4,
    "Price": 2,
    "RatingDimension3": 1,
    "rating-primary": 1,
    "Val1": 34,
    "Val2": 45
  },
  {
    "Design": 44,
    "Price": 23,
    "RatingDimension3": 12,
    "rating-primary": 1,
    "Val1": 56,
    "Val2": 22
  }
]

I tried following Jolt Spec

[
  {
    "operation": "shift",
    "spec": {
      "SecondaryRatings": {
        "*": {
          "*": {
            "*": {
              "@(2,Design)": "[&3].Design",
              "@(2,Price)": "[&3].Price",
              "@(2,RatingDimension3)": "[&3].RatingDimension3",
              "Val1": "[&3].Val1",
              "Val2": "[&3].Val2",
              "@(4,Rating)": "[&3].rating-primary"
            }
          }
        }
      }
    }
  }
]

But got following Output

[ 
 {
   "Design" : [ 4, 4, 4, 4, 4 ],
   "Price" : [ 2, 2, 2, 2, 2 ],
   "RatingDimension3" : [ 1, 1, 1, 1, 1 ],
   "rating-primary" : [ 1, 1, 1, 1, 1 ],
   "Val1" : 34,
   "Val2" : 45
 }, 
 {
   "Design" : [ 44, 44, 44, 44, 44 ],
   "Price" : [ 23, 23, 23, 23, 23 ],
   "RatingDimension3" : [ 12, 12, 12, 12, 12 ],
   "rating-primary" : [ 1, 1, 1, 1, 1 ],
   "Val1" : 56,
   "Val2" : 22
  } 
]

So as it is seen except for the last level values, all others are having array with repeated values. Can anybody help to what is missing or wrong in Jolt Spec?

Answer 1

You can directly walk through indexes of the outer array(SecondaryRatings) rather than inner one(Arr1) such as

[
  {
    "operation": "shift",
    "spec": {
      "SecondaryRatings": {
        "*": {
          "*": "[&1].&",
          "@(2,Rating)": "[&].rating-primary",
          "Arr1": {
            "*": {
              "*": "[&3].&"
            }
          }
        }
      }
    }
  }
]

in this case, no need to write all elements individually except for Rating