Recursively transform JSON using jolt

January 23, 2023

I am trying to transform a JSON into another JSON using JOLT.

My source JSON has the following format (the number of levels of child modules is not known):

{
    "modules": [
        {
            "id": "1",
            "modules": [
                {
                    "id": "1.1",
                    "modules": []
                },
                {
                    "id": "1.2",
                    "modules": [
                        {
                            "id": "1.2.1",
                            "modules": []
                        }
                    ]
                }
            ]
        },
        {
            "id": "2",
            "modules": [
                {
                    "id": "2.1",
                    "modules": []
                }
            ]
        }
    ]
}

My JOLT transformation spec looks like this:

[
    {
        "operation": "shift",
        "spec": {
            "modules": {
                "*": {
                    "id": "new_modules[&1].id"
                }
            }
        }
    }
]

The output I get is:

{
    "new_modules": [
      {
        "id": "1"
      },
      {
        "id": "2"
      }
    ]
}

What should I do to get all modules in the target JSON:

{
    "new_modules": [
      {
        "id": "1"
      },
      {
        "id": "1.1"
      },
      {
        "id": "1.2"
      },
      {
        "id": "1.2.1"
      },
      {
        "id": "2"
      },
      {
        "id": "2.1"
      }
    ]
}

I am adding some unrelated text below as stackoverflow complains that my question is mostly code and that I must add more details. Kindly let me know if I am missing details.

>Solution :

You can use this spec:

[
  {
    "operation": "shift",
    "spec": {
      "modules": {
        "*": {
          "id": "new_modules[].&",
          "modules": {
            "*": {
              "id": "new_modules[].&",
              "modules": {
                "*": {
                  "id": "new_modules[].&",
                  "modules": {
                    "id": "new_modules[].&"
                  }
                }
              }
            }
          }
        }
      }
    }
  }
]

You can’t have infinite levels in the jolt. But you can increase your levels in the above code.