Question : How to handle errors

[is984]

I implemented the following.

async function openSSHTunnel(config){
    const tOption = {
        autoClose: true
    }

    const sshOption = {
        host: config.ssh.host,
        port: config.ssh.port,
        username: config.ssh.username,
        password: config.ssh.password
    }
    const fOption = {
        dstAddr: config.ssh.dstHost,
        dstPort: config.ssh.dstPort
    }
    try {
        let res =await createTunnel(tOption, null, sshOption, fOption);
        return res
    } catch (e) {
        //Note: logger.write is a custom function
        logger.write(1, "Caught Error")
        logger.write(1, e)
        return Error(e)
    }
}

Passing incorrect SSH credentials to this code results in the following output and application termination.

Error : Caught Error
Error : Error: All configured authentication methods failed

C:\APPDir\node_modules\tunnel-ssh\index.js:94
            server.on('close', () => sshConnection.end());
                                                   ^

TypeError: Cannot read property 'end' of undefined
    at Server.<anonymous> (C:\APPDir\node_modules\tunnel-ssh\index.js:94:52)
    at Server.emit (events.js:314:20)
    at emitCloseNT (net.js:1658:8)
    at processTicksAndRejections (internal/process/task_queues.js:79:21)

The following can be gleaned from the above output

1. the authentication failure error is handled correctly
2. different error occurred after the error handle, so it could not be handled.

What should I do to resolve this situation (application terminated)?

[is984]

discovered that the cause was the order of function calls.
The addListServer is called first, which sets the close event on the server.
This defines the process of closing the sshConnection when the server terminates.
*See below.

   function addListenerServer(server) {
            if (tunnelOptionsLocal.reconnectOnError) {
                server.on('error', async () => {
                    server = await createServer(serverOptions);
                    addListenerServer(server);
                });
            }
            server.on('connection', onConnectionHandler);
            server.on('close', () => sshConnection.end()); //The line that causes
   }

After that, addListerSshConnection is called.
However, if the ssh connection fails here, the SSH connection failure is first returned as a reject.
Then the Server's Close event is executed and an error occurs as it tries to close the non-existent sshConnection.
However, since it has already returned a Reject, it is not properly handled and the application seems to crash.

Therefore, I believe that creating the SSH tunnel first and then the ServerListener will solve this problem.