Retrive value from payload and convert to CSV with Dataweave

Question

Hi I have this example payload. And I would save it to CSV but I don't need all value only a few.

{
    "ex": "names",
    "At": 0,
    "start": 50,
    "total": 506,
    "TypeI": [
        {
            "firstOne": "operations",
            "id": "28",
            "key": "192",
                "timespent": null,
                "project": {
                    "id": "10",
                    "key": "2",
                    "name": "PSM2",
                    "projectTypeKey": "software"
                }
            }
        },
        {
            "firstOne": "opera",
            "id": "27778",
            "key": null,
                "timespent": null,
                "project": {
                    "id": "10",
                    "key": "2",
                    "name": "PSM2",
                    "projectTypeKey": "software"
                }
        
            }
         }   
    ]
}

I don't want change the structure of this payload. I need only a few value from this and then I would like write it to CSV.

I got this payload with the same key and now I would like to save it to CSV. I have problem with the type. Now I got the string. But I need the array of object to save it in CSV.

{
  "TypeI": [
    {
      "firstOne": "operations",
       "date": "2022-03-25T14:12:25.702+0100",
      "id": "28",
      "key": "192"
    },
    {
      "firstOne": "opera",
      "date": null default " ", 
      "id": "27778",
      "key": null default " "
    }
  ]
}

This is example how it would like the CSV

firstOne;date;id;key
operations;2022-03-25T14:12:25.702+0100;28;192
opera;  ;27778;

Answer 1

Ok so I solve one problem.

    %dw 2.0
    import update from dw::util::Values
    output application/json
    ---
     TypeI : (payload.TypeI map ((item, index) -> {
        "firstOne": item.firstOne,
        "date": item.court.date,
        "id": item.id,
        "key": item.key
    } ))

And I got the json without change the structure of my json. Now the second part my question to save this to CSV.