How to create array using values from input array and another fields from hierarchy using JOLT

Question

I am trying to generate the JSON output based on JSON input using JOLT. Output should contain flatten array of objects for storing in db. Each object should contain following fields:

• rateplan = subscriptions.subscription[].products[specification=rateplan].code
• code = subscriptions.subscription[].options[].products[].code
• mandatory = subscriptions.subscription[].options[].mandatory
• multiple = subscriptions.subscription[].options[].multiple

It can be seen from expected output that count of objects is equal to count of subscriptions.subscription[].options[].products[]

Input JSON :

{
    "subscriptions": {
        "subscription": [{
                "name": "TA Generated subsr1",
                "specification": "Mobile Postpaid",
                "products": [{
                        "specification": "rateplan",
                        "code": "CODE1"
                    }, {
                        "specification": "addon",
                        "code": "P2PCF"
                    }, {
                        "specification": "addon",
                        "code": "AANSK"
                    }
                ],
                "options": [{
                        "category": "Installment Plan",
                        "products": [{
                                "specification": "addon",
                                "code": "TA_CODE2"
                            }, {
                                "specification": "addon",
                                "code": "TA_CODE3"
                            }
                        ],
                        "mandatory": "false",
                        "multiple": "false"
                    }, {
                        "category": "Internet",
                        "products": [{
                                "specification": "addon",
                                "code": "TA_CODE4"
                            }
                        ],
                        "mandatory": "false",
                        "multiple": "false"
                    }
                ]
            },
            {
                "name": "TA Generated subsr2",
                "specification": "Mobile Postpaid",
                "products": [{
                        "specification": "rateplan",
                        "code": "CODE11"
                    }, {
                        "specification": "addon",
                        "code": "P2PCF"
                    }, {
                        "specification": "addon",
                        "code": "AANSK"
                    }
                ],
                "options": [{
                        "category": "Internet",
                        "products": [{
                                "specification": "addon",
                                "code": "TA_CODE41"
                            }
                        ],
                        "mandatory": "false",
                        "multiple": "false"
                    }
                ]
            }
        ]
    }
}

Expected Output JSON:

[
    {
        "rateplan": "CODE1",
        "code": "TA_CODE2",
        "mandatory": "false",
        "multiple": "false"
    },
        {
        "rateplan": "CODE1",
        "code": "TA_CODE3",
        "mandatory": "false",
        "multiple": "false"
    },
    {
        "rateplan": "CODE11",
        "code": "TA_CODE41",
        "mandatory": "false",
        "multiple": "false"
    }
    
]

My jolt Spec:

[
  {
    "operation": "shift",
    "spec": {
      "subscriptions": {
        "subscription": {
          "*": {
            "products": {
              "*": {
                "specification": {
                  "rateplan": {
                    "@(2,code)": "o[].rateplan"
                  }
                }
              }
            },
            "options": {
              "*": {
                "products": {
                  "*": {
                    "@(code)": "o[&1].code",
                    "@(2,mandatory)": "o[&1].mandatory",
                    "@(2,multiple)": "o[&1].multiple"
                  }
                }
              }
            }
          }
        }
      }
    }
  }
]

Thanks in advance!

Answer 1

We might concentrically evaluate with respect to the indexes of the outermost array, namely "subscription", as the common factor. To apply that, we can qualify the identifiers by &7 and &5 respectively such as

[
  {
    "operation": "shift",
    "spec": {
      "@subscriptions.subscription": {
        "*": {
          "options": {
            "*": {
              "products": {
                "*": {
                  "@4,products": { // loop through the OUTER "products" array
                    "*": {
                      "@code": "&7_&3.c_s.@specification" // "match" code vs. "specification"
                    }
                  },
                  "@2,category": "&5_&1.category",
                  "code": "&5_&1.product",
                  "@2,mandatory": "&5_&1.mandatory",
                  "@2,multiple": "&5_&1.multiple"
                }
              }
            }
          }
        }
      }
    }
  },
  {
    "operation": "shift",
    "spec": {
      "*": {
        "c_s": { "rateplan": "[#3].&" }, // filter by the key "rateplan"
        "*": { "@": "[#3].&" } // other than the previously grouped attributes
      }
    }
  }
]

the demo on the site http://jolt-demo.appspot.com/ is :