03-server.js

const http = require('http')

const port = process.env.PORT || 1337

const server = http.createServer(response)

server.listen(port)
console.log(`Server listening on port ${port}`)

function response (req, res) {
  if (req.url === '/') return respondText(req, res)
  if (req.url === '/json') return respondJson(req, res)

  respondNotFound(req, res)
}

function respondText (req, res) {
  res.setHeader('Content-Type', 'text/plain')
  res.end('hi')
}

function respondJson (req, res) {
  res.setHeader('Content-Type', 'application/json')
  res.end(JSON.stringify({ text: 'hi', numbers: [1, 2, 3] }))
}

function respondNotFound (req, res) {
  res.writeHead(404, { 'Content-Type': 'text/json' })
  res.end('Not Found')
}