06-server.js

const fs = require('fs')
const express = require('express')

const port = process.env.PORT || 1337

const app = express()

app.get('/', respondText)
app.get('/json', respondJson)
app.get('/echo', respondEcho)
app.get('/static/*', respondStatic)

app.listen(port, () => console.log(`Server listening on port ${port}`))

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

function respondJson (req, res) {
  res.json({ text: 'hi', numbers: [1, 2, 3] })
}

function respondEcho (req, res) {
  const { input = '' } = req.query

  res.json({
    normal: input,
    shouty: input.toUpperCase(),
    characterCount: input.length,
    backwards: input
      .split('')
      .reverse()
      .join('')
  })
}

function respondStatic (req, res) {
  const filename = `${__dirname}/public/${req.params[0]}`
  fs.createReadStream(filename)
    .on('error', () => respondNotFound(req, res))
    .pipe(res)
}

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