yo.js

var gpio = require("gpio");

var gpio4 = gpio.export(4, {
   direction: "in",
   ready: function() {
     console.log('gpio has been exported');
   }
});

var sockets = [];

console.log('woohoo');

var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);

gpio4.on("change", function(val) {
  console.log("CHANGE ", val);
  for(var i = 0; i < sockets.length; i++){
    sockets[i].send('change', val);
  }
});

app.get('/', function(req, res){
  res.sendfile('index.html');
});

io.on('connection', function(socket){
  sockets.push(socket);
  socket.send('hi');
  console.log('a user connected');
});

app.get('/', function(req, res){
  res.sendfile('index.html');
});

io.on('connection', function(socket){
  sockets.push(socket);
  socket.send('hi');
  console.log('a user connected');
});

http.listen(3000, function(){
  console.log('listening on *:3000');
});