How to implement if-else condition in JoltTransforms in Apache NiFi?

I am preparing the jolt specification where I need to implement if-else condition but I am unable to achieve it. Please help me out.

Note :

1. if application-component-node object is coming in the input,
   then print that and drop application-component and application(if all three application object coming input).
2. if application-component object is coming in the input, then
   print that and drop application object (if all two
   application object arrays coming input).
3. if application object is only coming in the input, then print
   that.

For Example:

[
  {
    "severity": "ERROR",
    "type": "POLICY_CONTINUES_CRITICAL",
    "affectedEntities": [
      {
        "entityType": "POLICY",
        "name": "Exception Per Minute",
        "entityId": 3683
      },
      {
        "entityType": "APPLICATION",
        "name": "Teashop",
        "entityId": 6026
      },
      {
        "entityType": "APPLICATION-Component",
        "name": "Teashop",
        "entityId": 602667
      }
    ],
    "subType": "OVERALL_APPLICATION",
    "id": 92876278,
    "triggeredEntity": null
  }
]

Expected output:

[
  {
    "severity": "ERROR",
    "type": "POLICY_CONTINUES_CRITICAL",
    "affectedEntities": [
      {
        "entityType": "APPLICATION-Component",
        "name": "Teashop",
        "entityId": 602667
      }
    ],
    "subType": "OVERALL_APPLICATION",
    "id": 92876278,
    "triggeredEntity": null
  }
]

Here the expected output is application-component-node and drop the other two application object arrays

The priority among three object arrays is as follows:

• Priority 1 is for application-component-node and,
• Priority 2 is for application-component and,
• Priority 3 is for application

Note : Three object arrays are dynamic and they might come sometime only two object arrays come and sometimes only one object array may come.

You can use a lastElement function in a modify spec such as

[
  {
    "operation": "sort"
  },
  {
    "operation": "shift",
    "spec": {
      "*": {
        "*": "others.&",
        "app*": {
          "@": "app[].&"
        }
      }
    }
  },
  {
    "operation": "modify-overwrite-beta",
    "spec": {
      "app": "=lastElement(@(1,&))"
    }
  },
  {
    "operation": "shift",
    "spec": {
      "*": {
        "*": "[0].&"
      }
    }
  }
]

Edit : You can alternatively use the following transformation with
firstElement function in a modify spec based on your last edit :

[
  {
    "operation": "shift",
    "spec": {
      "*": {
        "*": "&",
        "aff*": {
          "*": {
            "*": "&2.@(1,entityType).&" // reconstruct subobjects with entityType keys
          }
        }
      }
    }
  },
  { // used for sorting purposes
    "operation": "shift",
    "spec": {
      "*": "&",
      "affectedEntities": {
        "APPLICATION-Component-Node": "&1[]",
        "APPLICATION-Component": "&1[]",
        "APPLICATION": "&1[]",
        "POLICY": "&1[]"
      }
    }
  },
  {
    "operation": "modify-overwrite-beta",
    "spec": {
      "aff*": "=firstElement(@(1,&))"
    }
  }
]

where the case-sensitivity of the entityTypes matter. The listing within the last shift transformation is used to order by those given entity types as in their presented letter cases.

the demo on the site http://jolt-demo.appspot.com/ is :