public/sketch.js

let secret;
function preload() {
  const socket = io();
  // client-side
  socket.on("connect", () => {
    console.log(socket.id); // x8WIv7-mJelg7on_ALbx
    socket.on("hello", (arg) => {
      //console.log(arg)
      secret = arg;
      console.log(secret)
    });
  });
}

function setup() {
  createCanvas(400, 400);
}

function draw() {
  background(220);
  textSize(32);
  text(secret, 10, 30);
  
}