Rename fields in nested arrays using JOLT transformation

Question

I want to rename fields in an array nested in an another array using JOLT transformation library.

1. One field to rename is a top level field in an array
2. Two fields to rename are inside a nested array

I have tried using wildcards but they are not giving me expected output. I am using JOLT 0.0.22 version.

Input JSON:

{
  "country": "usa",
  "state": [
    {
      "stateName": "TX",
      "location": "south",
      "cities": [
        {
          "name": "Austin",
          "pop": "1M"
        },
        {
          "name": "Dallas",
          "pop": "2M"
        }
      ]
    },
    {
      "stateName": "CA",
      "location": "west",
      "cities": [
        {
          "name": "SanFran",
          "pop": "3M"
        },
        {
          "name": "LosAngeles",
          "pop": "4M"
        }
      ]
    }
  ]
}

Expected Output :

{
  "country": "usa",
  "state": [
    {
      "stateName": "TX",
      "locatedIn": "south", // name change here
      "cities": [
        {
          "cityname": "Austin", // name change here
          "citypopulation": "1M" // name change here
        },
        {
          "cityname": "Dallas",
          "citypopulation": "2M"
        }
      ]
    },
    {
      "stateName": "CA",
      "locatedIn": "west",
      "cities": [
        {
          "cityname": "SanFran",
          "pop": "3M"
        },
        {
          "cityname": "LosAngeles",
          "citypopulation": "4M"
        }
      ]
    }
  ]
}

Answer 1

Spec

[
  {
    "operation": "shift",
    "spec": {
      "country": "country",
      "state": {
        "*": { // state array index
          "stateName": "state[&1].stateName",
          "location":  "state[&1].location",
          "cities": {
            "*": { // city array index
              "name": "state[&3].cities[&1].cityname",
              "pop":  "state[&3].cities[&1].citypopualtion"
            }
          }
        }
      }
    }
  }
]