Mule Dataweave - Add Nested and Simple attributes

Question

I need to add new attributes (simple and nested) to an existing JSON payload using Dataweave (3.0). I'm posting the sample payload below:

{
  "entities": [
    {
      "ID": "ABC",
      "sourceEnt": {
        "entityId": "100A",
        "entity": {
          "Code": "AB",
          "Idf1": "1pwe",
          "Idf2": null,
          "OrgAddr": [
            {
              "OrgAddrIdf1": "1pwe1",
              "Rank": 1,
              "Label": "One",
              "MainAddr": {
                "AddrLine1": "abc",
                "PoBox": 123,
                "DistrictCode": null
              }
            },
            {
              "OrgAddrIdf1": "1pwe2",
              "Rank": 2,
              "Label": "Two",
              "MainAddr": {
                "AddrLine1": "xyz",
                "PoBox": 456,
                "DistrictCode": null
              }
            }
          ]
        }
      }
    }
  ]
}

In the above payload, I need to add a new attribute ("StateCode": "null") to OrgAddr.MainAddr and also a new attribute called "Flag": "Yes", after OrgAddr. I can add the new "Flag" attribute at the end, but how can I modify a nested attribute (OrgAddr). Please note that I need to add the simple and nested attributes together.

Answer 1

very intersting use case. I was able to solve it by creating two helper functions that allows me to update the fields.

%dw 2.0
output application/json

/**
 * Updates the value of the specified field If the field doesn't exits it will be inserted at the bottom. Use this function with `with`. The with will receive the old value
 */
fun update(objectValue: Object, fieldName: String) = 
    (newValueProvider: (oldValue: Any, index: Number) -> Any) -> do {
        if(objectValue[fieldName]?)
            objectValue mapObject ((value, key, index) -> 
                if(key ~= fieldName)
                    {(key): newValueProvider(value, index)}
                else
                {(key): value}
            )
        else
            objectValue ++ {(fieldName): newValueProvider(null, 0)}
    }

/**
 * Updates the value at the specified index. If the index is bigger than the size it will be appended. Use this function with `with`. The with will receive the old value
 */
fun update(arrayValue: Array, indexToUpdate: Number) = 
    (newValueProvider: (oldValue: Any, index: Number) -> Any) -> do {
        if(arrayValue[indexToUpdate]?)
            arrayValue map ((value, index) -> 
                if(index == indexToUpdate)
                    newValueProvider(value, index)
                else
                    value
            )
        else
            arrayValue << newValueProvider(null, 0)
    }

---
payload update "entities" with (
    $ update 0 with (
        $ update "sourceEnt" with (
            $ update "entity" with (
                $ update "OrgAddr" with (
                        $ map ((item, index) -> item update "MainAddr" with ($ ++ {"StateCode": null}) )
                ) ++ {
                    "Flag" : "yes"
                }
            )
        )
    )
)

The two update function help me traverse the object and update the parts of the tree structure that need to be updated or modified.

Answer 2

Answer for 2.3 version of DataWeave

payload update {
    case entity at.entities[0].sourceEnt.entity -> do {
         entity update {
            case addresses at .OrgAddr ->  do {
            addresses map ((addr, index) -> addr  update {
                    case .MainAddr.StateCode! ->  null
            })
            }
            case .Flag! -> "Yes"
         }
    }
}

Answer 3

You can try this :

 %dw 1.0
    %output application/json
    %var pay=flatten payload.entities.sourceEnt.entity.OrgAddr
    ---
     {(pay)} mapObject {
            ($$):$ when ($$ as :string) != "MainAddr" otherwise {"StateCode": "null"} ++ $
        }