Increment value each time the function is called

Hi,
What I’m trying to do is that each time the function is called (when a message is received from the server), a variable is incremented by 1 from 49. Why? To create a new div for the new message.

Right now, i only return 50 each time, which is not what I want
How the function is called:

ws.onmessage = function(event){
        let newMessage = event.data;
        let messageRecopie = JSON.parse(newMessage);
        messageRecu(messageRecopie);
    };

And how I tried to increase i each time:

function messageRecu(obj){
    let chatMessage = obj;
    let i = (function(n){
            n += 1;
            return n;
    }(49));
    console.log(i);

    let chatWindow = document.getElementById('chat');
    let ligneChat = document.createElement('DIV');
    ligneChat.setAttribute('id','ligneChat'+i);
    chatWindow.appendChild(ligneChat);
(...)

I want to increment i each time a new message is received starting from 50 to infinite.
I don’t know if this is what you want, but ws is declared like this:

function connectionWebSocket(token){
    let ws = new WebSocket("ws://message.com:8000/ws");
...
ws.onmessage = function(event){
        let newMessage = event.data;
        let messageRecopie = JSON.parse(newMessage);
        messageRecu(messageRecopie);
    };
...

Could you show me a brief example of what you mean? And also, messageRecu isn’t inside connectionWebSocket, but I guess I could move it.

let messageCount = 50;

This would go inside the connectionWebSocket function. Without seeing the entire code for your project, I can only suggested moving messageRecu inside connectionWebSocket. Where else outside of connectionWebSocket would you even call messageRecu, since ws lives inside connectionWebSocket?

You’re right, I was making it more difficult than it really was, thanks you!