Use %XML.Node to walk a DOM

The following code walks a DOM using %XML.Node. It also prevents %XML.Writer to change whitespace. Run the code using the class method "test":

Class objectscript.walkDOM Extends %Persistent
{
    ClassMethod dfs(node As %XML.Node)
    {
        s entrynode=node.NodeId
        do {
        //element nodes with one whitespacetyped child are the ones we want to change
        if (node.NodeType=$$$xmlELEMENTNODE){
            s snode=node.NodeId     
            if (node.MoveToFirstChild())            
                {
                    i ('node.MoveToNextSibling()){
                        i (node.NodeType=$$$xmlWHITESPACENODE){
                            s node.NodeType=$$$xmlTEXTNODE
                            s node.NodeId=snode
                        }
                    }
            }
            s node.NodeId=snode     
        }   
        if (node.HasChildNodes()){
            d node.MoveToFirstChild()
            d ..dfs(node)
        }
        } while (node.NodeType'="" && node.MoveToNextSibling())
        s node.NodeId=entrynode
         
    }
     
    ClassMethod test()
    {
      set xml = "abcdefg"
     
      s reader=##class(%XML.Reader).%New()
      do reader.OpenString(xml)  
      set writer = ##class(%XML.Writer).%New()
      //do some magic
      d ..dfs(reader.Document)
       
      w !,"with indent=1:",!
      set writer.Indent = 1
      do writer.OutputToString()
      do writer.Document(reader.Document)
      w writer.GetXMLString()
      set writer.Indent = 0
      w !,"with indent=0:",!
      do writer.OutputToString()
      do writer.Document(reader.Document)
      w writer.GetXMLString()
    }
}

Here's a link to the code on GitHub: https://github.com/intersystems-community/code-snippets/blob/master/src/...