prevent empty messages or user

src/components/Chat.js

@@ -35,6 +35,10 @@ class Chat extends React.Component {
       console.log('Connected!')
       this.setState({ user: { socketId: socket.id } })
     })
+    socket.on('disconnect', () => {
+      console.log('Disconnected!')
+      this.setState({ user: { socketId: 'You' } })
+    })
   }
 
   componentDidUpdate() {
@@ -63,7 +67,14 @@ class Chat extends React.Component {
   }
   handleSubmit(e) {
     e.preventDefault()
-    const message = { userId: socket.id, id: uuid(), text: this.state.text }
+    if (this.state.user.socketId === '' || this.state.text === '') {
+      return
+    }
+    const message = {
+      userId: this.state.user.socketId,
+      id: uuid(),
+      text: this.state.text,
+    }
     const messages = this.state.messages.concat(message)
     this.setState({ messages, text: '' })
     socket.emit('message', message)