Mule Dataweave Replace Null with Specific Value - mule

Question

My request payload looks something like below:
{
"AllCodes": [
{
"Code1": "ABC"
},
{
"Code2": "TUV"
},
{
"Code3": "XYZ"
}
]
}
I have a function which will replace the values in the above with a certain value. The code that I've now is below:
%dw 1.0
%output application/json
%function LookUp(codes) codes mapObject {($$): $.code} //function to return string values for above codes
%var codeLookup = LookUp(sessionVars.OutputCodes)
%var FinalCodes = payload.AllCodes map codeLookup[$] joinBy ';'
--
FinalCodes
The output of sessionVars.OutputCodes is:
{
"CodeMaster": {
"PrimaryCodes": {
"PrimarySpecCodes": {
"ABC": {
"code": "ABC-String1"
},
"TUV": {
"code": "TUV-String2"
}
}
}
}
}
The output that I am expecting is:
"ABC-String1;XYZ-String2;XYZ"
As you can see above, since the function is returning the values for only "ABC" and "TUV" codes, my final output should have the original value if no function value found.
I was trying to use a default value before map operator. But it doesn't seem to work.

Answer 1

We get all the values for allCodes with $ pluck $, then if codes[$] is not found, we default to the value $. I believe you just need to add default $ to your original dataweave for it to work, but I gave a complete solution for other users on StackOverflow.
%dw 1.0
%output application/json
%var outputCodes =
{
"CodeMaster": {
"PrimaryCodes": {
"PrimarySpecCodes": {
"ABC": {
"code": "ABC-String1"
},
"TUV": {
"code": "TUV-String2"
}
}
}
}
}
%var allCodes =
{
"AllCodes": [
{
"Code1": "ABC"
},
{
"Code2": "TUV"
},
{
"Code3": "XYZ"
}
]
}
%var codes = outputCodes.CodeMaster.PrimaryCodes.PrimarySpecCodes mapObject {
($$): $.code
}
---
(flatten (allCodes.AllCodes map ($ pluck $))) map (
codes[$] default $
) joinBy ';'
this produces:
"ABC-String1;TUV-String2;XYZ"

Answer 2

There are various ways to solve this. One could be as follows:
%dw 1.0
%output application/json
%var payload2= { "CodeMaster": { "PrimaryCodes": { "PrimarySpecCodes": { "ABC": {"code": "ABC-String1"}, "TUV": {"code": "TUV-String2"} } } } }
%var codes = payload2.CodeMaster.PrimaryCodes.PrimarySpecCodes mapObject {
($$) : $.code
}
%var finalCodes = (payload.AllCodes map {
a: $ mapObject {
a1: codes[$] default $
}
}.a.a1) joinBy ";"
---
finalCodes