This is a typical XML-RPC server written in JavaScript as of today. There's still more cleanup to do, for example, you shouldn't have to specify flPostEnabled in config, since XML-RPC calls are only made via POST, it can be handled at the lower level.

typicalXmlRpcServer.js

const xmlrpc = require ("davexmlrpc");
const utils = require ("daveutils");
const davehttp = require ("davehttp"); 
const mail = require ("davemail");
const fs = require ("fs");

var config = {
	port: 1417,
	flPostEnabled: true,
	flLogToConsole: true, 
	xmlRpcPath: "/rpc2"
	}

xmlrpc.startServerOverHttp (config, function (xmlRpcRequest) {
	function mailSend (params, callback) {
		var recipient = params [0];
		var title = params [1];
		var mailtext = params [2];
		var sender = params [3];
		mail.send (recipient, title, mailtext, sender, function (err, data) {
			callback (err, data);
			});
		}
	switch (xmlRpcRequest.verb) {
		case "mail.send":
			mailSend (xmlRpcRequest.params, xmlRpcRequest.returnVal);
			return (true); //we handled it
		}
	return (false); //we didn't handle it
	});