Null Check in Jolt while converting string to integer For an Object

I am doing conversion of string to integer/double in my jolt spec. If elements does not come in request, then empty object is coming in response. Instead I do not want to pass that object itself as its empty.

Input Request Working:

{
  "data": {
    "first": "1",
    "second": "2"
  }
}

Jolt Spec:

[
  {
    "operation": "shift",
    "spec": {
      "data": {
        "first": "datas.firstTag",
        "second": "datas.second.secondTag"
      }
    }
  },
  {
    "operation": "modify-overwrite-beta",
    "spec": {
      "datas": {
        "firstTag": "=toInteger",
        "second": {
          "secondTag": "=toInteger"
        }
      }
    }
  },
  {
    "operation": "modify-overwrite-beta",
    "spec": {
      "*": "=recursivelySquashNulls"
    }
  }
]

Output if tag is there in request:

{
  "datas" : {
    "firstTag" : 1,
    "second" : {
      "secondTag" : 2
    }
  }
}

But when input request is like below where I do not get second tag:

{
  "data": {
    "first": "1"
  }
}

Current Output:

{
  "datas" : {
    "firstTag" : 1,
    "second" : { }
  }
}

Getting second object as empty

"second" : { }

Expected Output:

{
  "datas" : {
    "firstTag" : 1
  }
}

Please help to fix this issue.

Answer

Rethink in a dynamical manner by using ampersand placeholders such as

[
  {
    "operation": "shift",
    "spec": {
      "*": { 
        "first": "&1s.&Tag",
        "*": { "@(1,&)": "&2s.&.&Tag" }
      }
    }
  },
  {
    "operation": "modify-overwrite-beta",
    "spec": {
      "*": {
        "firstTag": "=toInteger",
        "*": {
          "*": "=toInteger"
        }
      }
    }
  }
]

the suffixed integers for those ampersands represents the level to go up to grab the desired value such as &1 and &2 stand for data, & without integer suffixes represent the value from the current level.

“*” wildcard represents the rest of the elements, other than first in this case(you might have third, fourth … as other elements to be formatted like the second)

first case :

second case :

Edit : For the current case which’s mentioned within the edit in order to get

{
  "datas" : {
    "firstTag" : "1",
    "second" : {
      "secondTag" : "2",
      "secondNew" : "3"
    }
  }
}

from the input

{
  "data": {
    "first": "1",
    "second": "2",
    "secondNew": "3"
  }
}

which had a new entry “secondNew”: “3”, you’ll need to write each key explicitly within the spec such as

[
  {
    "operation": "shift",
    "spec": {
      "*": {
        "first": "&1s.&Tag",
        "second": "&1s.&.&Tag",
        "secondNew": "&1s.second.&"
      }
    }
  },
  {
    "operation": "modify-overwrite-beta",
    "spec": {
      "*": {
        "firstTag": "=toInteger",
        "*": {
          "*": "=toInteger"
        }
      }
    }
  }
]

in order to combine the rest of the elements under common object.