Sample of strange nodejs error

strange-node-error.js

// Starting server returning 'okay' to everyone.
require('http').createServer(function(req, res){
  process.nextTick(function(){
    res.end('okay')
  })
}).listen(3000)

// Calling server.
var data = []
var opts = {host: 'localhost', port: 3000, path: '/', method: 'get'}
var req = require('http').request(opts, function(res){
  res.on('data', function(chunk){data.push(chunk)})
  res.on('end', function(){console.log(data.join())})
})
req.on('error', function(err){console.log(err)})
req.write("hello")
req.end()