How to read / write comments

[maku]

I have to manipulate an existing XML-File which contains comments.

How can I do this without loosing the comments in the file?

[Omega-Ariston]

Here's a simple demo I wrote. You can take it as a reference :) tagNameProcessor is executed when entering a node while validator is executed when leaving a node.

    const xmlStr = `
    <xml>
        xml node text
        <node1>
            <!-- node1 node comment -->
            node1 node text
            <node2>
                <!-- node2 node comment -->
                node2 node text
            </node2>
        </node1>
        <node3>
            node3 node text
            <!-- node3 node comment -->
        </node3>
        <!-- xml node comment -->                    
    </xml>
    `;

    let currNode = "";

    const tagNameProcessor = function (name) {
        currNode = name;
        return name;
    };

    const validator = function (xpath, node, obj) {
        currNode = xpath.substring(0, xpath.lastIndexOf("/"));
        currNode = currNode.substr(currNode.lastIndexOf("/") + 1);
        return obj;
    };

    const parser = xml2js.Parser({ tagNameProcessors: [tagNameProcessor], validator: validator });

    parser.saxParser.oncomment = function (str) {
        console.log("node:", currNode, ",comment:", str);
    };

    parser.parseString(xmlStr, function (err, result) {
        //do something
    });

output:

node: node1 ,comment:  node1 node comment 
node: node2 ,comment:  node2 node comment 
node: node3 ,comment:  node3 node comment 
node: xml ,comment:  xml node comment 

[bstopp]

How does one parse, process, manipulate object tree, and the build the XML output, but not lose comments? AFAICT this doesn't seem possible?