How to remove the attribute that returns null in XML using Mule 4?

Question

I need to remove "null" attributes from an XML using dataweave 2.0,

I tried skipNullOn="everywhere" and skipOnNull="attribute" is working only on elements not on attributes.

Error on using skipNullOn :

"Option `skipOnNull` is not valid. Valid options are: `writeDeclaration`, `indent`, `doubleQuoteInDeclaration`, `encoding`, `escapeGT`, `defaultNamespace`, `bufferSize`, `inlineCloseOn`, `onInvalidChar`, `writeNilOnNull`, `escapeCR`, `skipNullOn`, `writeDeclaredNamespaces`, `deferred`

Input XML:

<?xml version="1.0" encoding="UTF-8"?>
<DTOApplication id="Application-1660258480-1493174910" ApplicationNumber="AP-00006354">
    <DTOLine id="Line-101746978-972142087" StatusCd="Active" >
        <DTOCoverage id="Coverage-1713637162-341585712" CoverageCd="MINP" >
            <DTOSteps>
                <DTOStep Order="1" Name="Premium" value="8" factor="8"/>
                <DTOStep Order="2" Name="Term Factor" value="9" factor="9">
                    <DTOSteps>
                        <DTOStep Order="1" Name="Minimum Premium" value="10" factor="10"/>
                        <DTOStep Order="2" Name="Rated Premium" value="null" factor="null"/>
                    </DTOSteps>
                </DTOStep>
            </DTOSteps>
        </DTOCoverage>
        <DTOCoverage id="Coverage-763105832-915106268" CoverageCd="TRIAL">
            <DTOSteps id="Steps-Coverage-763105832-915106268">
                <DTOStep Order="1" Name="Premium" value="18" factor="18" />
            </DTOSteps>
        </DTOCoverage>
    </DTOLine>
    <DTOCoverage id="Coverage-863105832-915106268" CoverageCd="EBRK" >
        <DTOSteps id="Steps-Coverage-863105832-915106268">
            <DTOStep Order="1" Name="Base Rate" value="null" factor="null"/>
        </DTOSteps>
    </DTOCoverage>
</DTOApplication>

Expected XML Output : https://github.com/Manikandan99/Map_request/blob/main/null_removed.xml

Any ideas please on how to remove attribute return "null" using dataweave 2.0?

Answer 1

Try the below DW

DW

%dw 2.0
output application/xml
var updateval = (element) ->
  element mapObject (value, key) -> {
    (key) @(
        (
          if (key.@?)
            (key.@ mapObject ((avalue, akey) -> { 
                    ((akey): avalue) if (avalue != "null")
                }))
          else {}
        )
    ) :
    if (value is Object)
      updateval(value)
    else value
  }
---
updateval(payload)

Output

<?xml version='1.0' encoding='UTF-8'?>
<DTOApplication id="Application-1660258480-1493174910" ApplicationNumber="AP-00006354">
  <DTOLine id="Line-101746978-972142087" StatusCd="Active">
    <DTOCoverage id="Coverage-1713637162-341585712" CoverageCd="MINP">
      <DTOSteps>
        <DTOStep Order="1" Name="Premium" value="8" factor="8"/>
        <DTOStep Order="2" Name="Term Factor" value="9" factor="9">
          <DTOSteps>
            <DTOStep Order="1" Name="Minimum Premium" value="10" factor="10"/>
            <DTOStep Order="2" Name="Rated Premium"/>
          </DTOSteps>
        </DTOStep>
      </DTOSteps>
    </DTOCoverage>
    <DTOCoverage id="Coverage-763105832-915106268" CoverageCd="TRIAL">
      <DTOSteps id="Steps-Coverage-763105832-915106268">
        <DTOStep Order="1" Name="Premium" value="18" factor="18"/>
      </DTOSteps>
    </DTOCoverage>
  </DTOLine>
  <DTOCoverage id="Coverage-863105832-915106268" CoverageCd="EBRK">
    <DTOSteps id="Steps-Coverage-863105832-915106268">
      <DTOStep Order="1" Name="Base Rate"/>
    </DTOSteps>
  </DTOCoverage>
</DTOApplication>