npm i socket.io -S
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<script src="<https://cdn.socket.io/socket.io-3.0.1.min.js>"></script>
<title>Hello Socket.io!</title>
</head>
<body>
<script>
const socket = io("ws://localhost:3000");
socket.on("connect", () => {
socket.send("Hello!");
});
socket.on("message", (data) => {
console.log(data);
});
</script>
</body>
</html>
app.js
const socketIo = require("socket.io");
const io = socketIo(3000);
: Errors are normal because it's not a valid url. It's fine.
app.js
const socketIo = require("socket.io");
const io = socketIo(3000, {
cors: {
origin: "*",
methods: ["GET", "POST"]
}
});