server.js

const http = require('http')
const app = require('./app')
const { Logger } = require('./src/utils')

const port = normalizePort(process.env.PORT || '8080')
const logger = Logger.init()

const server = http.createServer(app)

app.set('port', port)

server.listen(port)
server.on('error', onError)
server.on('listening', onListening)

function normalizePort(val) {
  const port = parseInt(val, 10)

  if (isNaN(port)) {
    return val
  }

  if (port >= 0) {
    return port
  }

  return false
}

function onError(error) {
  if (error.syscall !== 'listen') {
    throw error
  }

  const bind = typeof port === 'string' ? `Pipe ${port}` : `Port ${port}`

  switch (error.code) {
  case 'EACCES':
    logger.error(`${bind} requires elevated privileges`)

    process.exit(1)

    break
  case 'EADDRINUSE':
    logger.error(`${bind} is already in use`)

    process.exit(1)

    break
  default:
    throw error
  }
}

function onListening() {
  const addr = server.address()
  const bind = typeof addr === 'string' ? `pipe ${addr}` : `port ${addr.port}`

  logger.info(`Listening on ${bind}`)
}