Create socket connection and send a message

package.json

@@ -21,6 +21,7 @@
   "dependencies": {
     "express": "^4.15.3",
     "react": "^15.6.1",
-    "react-dom": "^15.6.1"
+    "react-dom": "^15.6.1",
+    "socket.io": "^2.0.3"
   }
 }

server.js

@@ -7,6 +7,12 @@ app.get('/hello', function (req, res) {
   res.send('Hello World!')
 })
 
-app.listen(3000, function () {
+const server = app.listen(3000, function () {
   console.log('Example app listening on port 3000!')
 })
+
+const io = require('socket.io').listen(server);
+
+io.on('connection', (socket) => {
+    socket.emit('message', 'hello socket');
+});

src/app.js

@@ -1,4 +1,5 @@
 import React from 'react';
+import io from 'socket.io-client';
 
 export default class App extends React.Component {
     constructor(props) {
@@ -8,9 +9,30 @@ export default class App extends React.Component {
             ioState: {
                 dout: [false],
             },
+            socket: io.connect()
         }
     }
 
+    componentDidMount() {
+        this.connect();
+    }
+
+    componentWillUnmount() {
+        this.setState({socket: this.state.socket.removeAllListeners()});
+    }
+
+    connect() {
+        let socket = this.state.socket;
+
+        socket.on('connect', () => {
+            console.log('connected');
+        });
+
+        socket.on('message', (data) => {
+            console.log(data);
+        });
+    }
+
     doutSet(pin, value) {
         this.setState({
             ioState: {