[Node.js]30. Level 6: Listen 'Question' from client, and then Answer the Question

Clients can also answer each other questions, so let's build that feature by first listening for the'answer' event on the client, which will send us both the question and answer, which we want to broadcast out to the rest of the connected clients.

var express = require('express');
var app = express.createServer();
var socket = require('socket.io');
var io = socket.listen(app);

io.sockets.on('connection', function(client) {
  console.log("Client connected...");

  // listen for answers here

  client.on('question', function(question) {
    client.get('question_asked', function(err, asked) {
      if(!asked) {
        client.set('question_asked', true);
        client.broadcast.emit('question', question);
      }
    });
     //can pass two or more params in callback function
     client.on('answer', function(question,answer) {
       client.broadcast.emit('answer',question, answer);
     });
  });
});

Now on the client, listen for the 'answer' event and call the answerQuestion function, passing in both the question and the answer that was broadcasted from the server.

<script src="/socket.io/socket.io.js" />

<script>
  var server = io.connect('http://localhost:8080');

  server.on('question', function(question) {
    insertQuestion(question);
  });

server.on('answer', function(question, answer){
    answerQuestion(question, answer);
});

  //Don't worry about these methods, just assume
  //they insert the correct html into the DOM
  // var insertQuestion = function(question) {
  // }

  // var answerQuestion = function(question, answer) {
  // }
</script>