MTLS: send client certificate in nodejs soap - and check server certificate

Question

I'm trying to send a client certificate from a nodejs app using node-soap

const clientURL = 'prod.wsdl';
const wsdl_options = {
           wsdl_options: {
               "cert": fs.readFileSync('/etc/ssl/certs/client.crt'),
               "key": fs.readFileSync('/etc/ssl/certs/client.key'),
           }
};
soap.createClient(clientURL, wsdl_options,  function (err, client) {
  if (!err) {
    client[my-method](args, function (error, result) {
    if (error) console.log(JSON.stringify(error))
  
  }
})

But I'm getting an error: {"errno":"EPROTO","code":"EPROTO","syscall":"write"}

When I'm sending a curl, the server gets my request with the correct cert:

curl -X POST https://host:4431/func --cert /etc/ssl/certs/client.crt --key /etc/ssl/certs/client.key

what can be the problem here? am I missing something at wsdlOptions?

Also, My customer gave me the certificate of the soap-server (and NOT the ca itself) and I need to check the ssl certificate of this response against the one he gave me.

How can I do that?

for request library we can do: res.connection.getPeerCertificate() / res.connection.getPeerX509Certificate() like this.

UPDATE:

I found the solution to the first issue with the client certificate and key.

I was missing:

client.setSecurity

After creating the proxy!

For createClient, there is no need to put the cert and key. So the code now looks like this:

const clientURL = 'prod.wsdl';

soap.createClient(clientURL, {},  function (err, client) {
  if (!err) {
    client.setSecurity(new soap.ClientSSLSecurity('/path/to/key','path/to/cert'));
    client[my-method](args, function (error, result) {
        ...
  }
})

Now how can I get the certificate of the server from the response and compare it to the one I have?