JOLT Transformation, copy an attribute into a dict at same level

Question

Below is my JSON

[
  {
    "id": "0",
    "bucket_attr1": "test1",
    "buckets": ["abc", "def", "mhf"]
  },
  {
    "id": "1",
    "bucket_attr1": "test2",
    "buckets": ["abc", "ghi"]
  }
]

I want to copy id and bucket_attr1 into each map in the buckets array, such that output is as follows

[
  {
    "bucket_id": "abc",
    "bucket_attr1": "test1",
    "id": "0"
  },
  {
    "bucket_id": "def",
    "bucket_attr1": "test1",
    "id": "0"
  },
  {
    "bucket_id": "mhf",
    "bucket_attr1": "test1",
    "id": "0"
  },
  {
    "bucket_id": "abc",
    "bucket_attr2": "test2",
    "id": "1"
  },
  {
    "bucket_id": "ghi",
    "bucket_attr2": "test2",
    "id": "1"
  }
]

I tried several ways including what is mentioned here after slight modification, but it did not work. Jolt Transformation to move an attribute in each element of the array

Answer 1

You can use the following shift transformation specs :

[
  {// separate by indexes from two different levels
    "operation": "shift",
    "spec": {
      "*": {
        "buckets": {
          "*": {
            "@": "&3_&1.bucket_id",
            "@2,id": "&3_&1.id",
            "@2,bucket_attr1": "&3_&1.bucket_attr1"
          }
        }
      }
    }
  },
  {// get rid of the separator keys of the objects
    "operation": "shift",
    "spec": {
      "*": "[]"
    }
  }
]

or we can make it more dynamic such as

[
  { // separate by indexes from two different levels
    "operation": "shift",
    "spec": {
      "*": {
        "*": "&1.others.&", // nest other elements within a common object to be used within the upcoming spec
        "buckets": {
          "*": {
            "@": "&3.&2[&1].bucket_id"//rename as desired
          }
        }
      }
    }
  },
  { //get three independent arrays 
    "operation": "shift",
    "spec": {
      "*": {
        "buckets": {
          "*": {
            "@2,others": { "*": "[#6].&" },
            "*": "[#5].&"
          }
        }
      }
    }
  },
  { //dissipate each array elements to different individual objects
    "operation": "shift",
    "spec": {
      "*": {
        "*": {
          "*": "[&].&1"
        }
      }
    }
  }
]

the demo for the second one on the site https://jolt-demo.appspot.com/ is :