Multiple connections, but single websocket.on("message") event emitter - node.js

Question

I have a single device establishing two WebSocket connections to the Einaros/ws WebSocket server. Whenever the second WebSocket connection sends a message to the server, only the first websocket.on("message") event emitter responds. There is no way to differentiate which WebSocket the message is coming from because there seems to be only a single websocket.on("message") event emitter object.
How can I differentiate from which WebSocket connection the message is being received from without passing an ID from the client side?
I apologize if I am overlooking something simple, I am a node.js and coding novice. From the code below it looks like there should be separate event emitter objects created for each WebSocket connection so that the server knows which connection the message is coming from. My code looks like this:
var connections = new Map();
var idCounter = 0;
wss.on("connection", function connection(ws) {
var connectionID = idCounter++;
connections.set(connectionID, ws);
var session = connections.get(connectionID);
session.on("message", function incoming(message) {
session.send(message);
}
}
--- Update ---
I have performed another test. With the code below "objectTest" contains the unique WebSocket connection distinguished by 'sec-websocket-key' printed to the console. However "this.send(message);" and "console.log(this);" both refer to the first established WebSocket connection even while "objectTestMap" contains the second "objectTest" that is unique.
var connections = new Map();
var idCounter = 0;
wss.on("connection", function connection(ws) {
var connectionID = idCounter++;
connections.set(connectionID, ws);
var session = connections.get(connectionID);
var sendThis = String(connectionID);
session.send(sendThis);
var objectTestMap = new Map();
var objectTest = session.on("message", function incoming(message) {
this.send(message);
console.log(this);
});
objectTestMap.set(connectionID, objectTest);
console.log(objectTestMap.get(connectionID));
});

Answer 1

Their was an error on my client application that was connecting to the server. No problems with WS and the above code works as it should.