soap client - server communication in Nodejs

[iott]

complete example:
// server.js

var soap = require('strong-soap').soap;
var http = require('http');

var myService = {
    CheckUserName_Service: {
        CheckUserName_Port: {
            checkUserName: function(args, soapCallback) { 
                console.log('checkUserName: Entering function..');
                soapCallback(args);
            }
        }
    }   
};


var xml = require('fs').readFileSync('check_username.wsdl', 'utf8');

var server = http.createServer(function(request,response) {
    response.end("404: Not Found: " + request.url);
});

var port = 8000;
server.listen(port);

var soapServer = soap.listen(server, '/test', myService, xml);
soapServer.log = function(type, data) {
    console.log('Type: ' + type + ' data: ' + data);
};

console.log('SOAP service listening on port ' + port);

//client.js

"use strict";

var soap = require('strong-soap').soap; 
var url = 'http://localhost:8000/test?wsdl';

var options = { endpoint: 'http://localhost:8000/test'};
var requestArgs = { userName: "TEST_USER" };
let method="checkUserName";
soap.createClient(url, options, function(err, client) {
  if (err) {
      console.error("An error has occurred creating SOAP client: " , err);  
  } else {
    console.log("client:",client);
      var description = client.describe();
      console.log("Client description:" , description);
      // var method = client.checkUserName;
      var method = client["CheckUserName_Service"]["CheckUserName_Port"]["checkUserName"];
      console.log(method,111);
      method(requestArgs, function(err, result, envelope, soapHeader) {
      // client.checkUserName(requestArgs, function(err, result, envelope, soapHeader) {
        //response envelope
        console.log('Response Envelope: \n' + envelope);
        //'result' is the response body
        console.log('Result: \n' + JSON.stringify(result));
      });
  }
});

//check_username.wsdl

<definitions name = "CheckUserNameService"
   targetNamespace = "http://www.examples.com/wsdl/CheckUserNameService.wsdl"
   xmlns = "http://schemas.xmlsoap.org/wsdl/"
   xmlns:soap = "http://schemas.xmlsoap.org/wsdl/soap/"
   xmlns:tns = "http://www.examples.com/wsdl/CheckUserNameService.wsdl"
   xmlns:xsd = "http://www.w3.org/2001/XMLSchema">

   <message name = "CheckUserNameRequest">
      <part name = "userName" type = "xsd:string"/>
   </message>
   <message name = "CheckUserNameResponse">
      <part name = "status" type = "xsd:string"/>
   </message>
   <portType name = "CheckUserName_PortType">
      <operation name = "checkUserName">
         <input message = "tns:CheckUserNameRequest"/>
         <output message = "tns:CheckUserNameResponse"/>
      </operation>
   </portType>

   <binding name = "CheckUserName_Binding" type = "tns:CheckUserName_PortType">
      <soap:binding style = "rpc"
         transport = "http://schemas.xmlsoap.org/soap/http"/>
      <operation name = "checkUserName">
         <soap:operation soapAction = "checkUserName"/>
         <input>
            <soap:body encodingStyle = "http://schemas.xmlsoap.org/soap/encoding/" namespace = "urn:examples:CheckUserNameService" use = "encoded"/>
         </input>
         <output>
            <soap:body encodingStyle = "http://schemas.xmlsoap.org/soap/encoding/" namespace = "urn:examples:CheckUserNameService" use = "encoded"/>
         </output>
      </operation>
   </binding>

   <service name = "CheckUserName_Service">
      <documentation>WSDL File for CheckUserNameService</documentation>
      <port binding = "tns:CheckUserName_Binding" name = "CheckUserName_Port">
         <soap:address
            location = "http://www.examples.com/CheckUserName/" />
      </port>
   </service>
</definitions>