Create static/chat.js

static/chat.js

@@ -0,0 +1,27 @@
+(() => {
+  const params = new URLSearchParams(window.location.search);
+  const room = params.get('room');
+  const socket = io();
+  const chatDiv = document.getElementById('chat');
+  document.getElementById('send').onclick = () => {
+    const text = document.getElementById('msg').value;
+    socket.emit('chat', {room, msg: text});
+  };
+  socket.on('chat', data => {
+    const b = document.createElement('div');
+    b.textContent = data.msg;
+    chatDiv.append(b);
+  });
+  document.getElementById('leave').onclick = () => {
+    if (confirm('Are you sure you want to leave?')) {
+      socket.emit('leave', {room});
+      window.location = '/';
+    }
+  };
+  socket.on('status', data => {
+    const s = document.createElement('div');
+    s.textContent = data.msg;
+    chatDiv.append(s);
+  });
+  socket.on('left', () => location='/');
+})();