How to remove key value pair from json using Dataweave in mule4 - json

Question

I want to remove a key from json payload if its empty for eg.
{
"transactionDetails": {
"maintenanceType": null,
"transactionDate": "2021-10-07T05:38:38.44-05:00"
},
"account": {
"agentOfRecord": {
"type": "true",
"rateType": ""
},
"subAccounts": {
"subAccount": [{
"agentOfRecord": []
}]
}
}
}
In the above example two keys which are empty "rateType" and "agentOfRecord". How can I remove this two keys from the payload.
Expected result will be lyk this
{
"transactionDetails": {
"maintenanceType": null,
"transactionDate": "2021-10-07T05:38:38.44-05:00"
},
"account": {
"agentOfRecord": {
"type": "true"
},
"subAccounts": {
"subAccount": [{
}]
}
}
}
I tried below code but not working its not filtering the actual key
%dw 2.0
output application/json
---
payload filterObject ((value, key) -> (key as String != "Test"))

Answer 1

The variable filterList is not used directly, so that the function is more reusable. The variable could be replaced by a list obtained from a configuration or a database.
This script should remove all keys mentioned in filterList that are 'empty'. I used a custom empty function, because the built-in isEmpty() function also includes empty objects, and I wasn't sure if you wanted that. Otherwise you can use the built-in version.
%dw 2.0
output application/json
var filterList=["rateType", "agentOfRecord"]
fun isEmptyCustom(x)=
x match {
case is Array -> sizeOf(x) == 0
case is String -> sizeOf(x) == 0
else -> false
}
fun filterKey(k, v, f)= !isEmptyCustom(log("v",v)) or
!(f contains (log("k", k) as String))
fun filteKeyRecursive(x, f) =
x match {
case is Object ->
x
filterObject ((value, key, index) -> filterKey(key, value, f))
mapObject ($$): filteKeyRecursive($, f)
case is Array -> x map filteKeyRecursive($, f)
else -> x
}
---
filteKeyRecursive(payload, filterList)
Update: fixed the condition.