net12.ts

net.createServer()
  .listen(PORT, IP, BACKLOG)
  .on('connection', socket => {
    console.log('new connection')
    socket
      .on('data', buffer => {
        console.log('data')
        socket.write(fibonacci(100))
        console.log('done with connection')
        socket.end()
      })
  })

const fibonacci = (n: number) => (n < 2) ? n
  : fibonacci(n - 2) + fibonacci(n - 1)