Manipulate JSON input to produce a JSON list of items

I am trying to find a way to manipulate my input JSON so that I can pass it to a map function which would call another step function for processing.

My input JSON looks like this:

  "notificationType": "Received",
  "mail": {
    "timestamp": "2023-05-31",
    "source": "source@gmail.com",
    "messageId": "xyz",
    "destination": [
      "email1",
      "email2"
    ],
    "headersTruncated": false,
    "headers": [...],
    "commonHeaders": {
      ....
    }
}

I would like to produce a JSON that would look like this:

[{
  "email_address": "email1"
  "notificationType": "Received",
  "mail": {
    "timestamp": "2023-05-31T16:24:48.413Z",
    "source": "source@gmail.com",
    "messageId": "xyz",
    "destination": [
      "email1",
      "email2"
    ],
    "headersTruncated": false,
    "headers": [...],
    "commonHeaders": {
      ....
    }
},
{
  "email_address": "email2"
  "notificationType": "Received",
  "mail": {
    "timestamp": "2023-05-31T16:24:48.413Z",
    "source": "source@gmail.com",
    "messageId": "xyz",
    "destination": [
      "email1",
      "email2"
    ],
    "headersTruncated": false,
    "headers": [...],
    "commonHeaders": {
      ....
    }
}]

This list would be passed to a map step which would execute another step function.
Or if there is any way to pass original input to a Map along with $.mail.destination list that would also work, but I couldn't find a way to do that either.

Couldn't find anything in AWS built in functions to manipulate json in such a way

If I understand correctly, you have an single JSON object as input. That object contains an array of items called destination. You want to use this to create an array of items, one for each destination, that also includes some of the data from original object as context.

If so, I'd use a Map state to do this. See the Amazon State Language (ASL) below to illustrate. This uses an Map state with your destination array as the ItemsPath which means you will have one iteration per destination. It also uses ItemSelector to shape the input to each of the iterations to include common data from the original input. It then uses Parameters in a Pass State to shape the item as you specified.

{
  "StartAt": "Generate Input",
  "States": {
    "Generate Input": {
      "Type": "Pass",
      "Result": {
        "notificationType": "Received",
        "mail": {
          "timestamp": "2023-05-31",
          "source": "source@gmail.com",
          "messageId": "xyz",
          "destination": [
            "email1",
            "email2"
          ],
          "headersTruncated": false,
          "headers": [
            "header1",
            "header2",
            "header3"
          ],
          "commonHeaders": {
            "commonHeader1": "value1",
            "commonHeader2": "value2",
            "commonHeader3": "value3"
          }
        }
      },
      "Next": "Map"
    },
    "Map": {
      "Type": "Map",
      "ItemProcessor": {
        "ProcessorConfig": {
          "Mode": "INLINE"
        },
        "StartAt": "Shape Item",
        "States": {
          "Shape Item": {
            "Type": "Pass",
            "End": true,
            "Parameters": {
              "email_address.$": "$.itemValue",
              "notificationType.$": "$.originalInput.notificationType",
              "mail.$": "$.originalInput.mail"
            }
          }
        }
      },
      "End": true,
      "ItemsPath": "$.mail.destination",
      "ItemSelector": {
        "originalInput.$": "$",
        "itemValue.$": "$$.Map.Item.Value"
      }
    }
  }
}

This will then yield the following result, which I think is what you wanted. You could then pass this into another Map state. Or this might allow you to just add your processing logic after the Pass state in the ItemProcessor defined above.

[
  {
    "email_address": "email1",
    "mail": {
      "timestamp": "2023-05-31",
      "source": "source@gmail.com",
      "messageId": "xyz",
      "destination": [
        "email1",
        "email2"
      ],
      "headersTruncated": false,
      "headers": [
        "header1",
        "header2",
        "header3"
      ],
      "commonHeaders": {
        "commonHeader1": "value1",
        "commonHeader2": "value2",
        "commonHeader3": "value3"
      }
    },
    "notificationType": "Received"
  },
  {
    "email_address": "email2",
    "mail": {
      "timestamp": "2023-05-31",
      "source": "source@gmail.com",
      "messageId": "xyz",
      "destination": [
        "email1",
        "email2"
      ],
      "headersTruncated": false,
      "headers": [
        "header1",
        "header2",
        "header3"
      ],
      "commonHeaders": {
        "commonHeader1": "value1",
        "commonHeader2": "value2",
        "commonHeader3": "value3"
      }
    },
    "notificationType": "Received"
  }
]