Static file server / pure Node.js

index.js

// https://stackoverflow.com/questions/7268033/basic-static-file-server-in-nodejs

const http = require('http')
const url = require('url')
const fs = require('fs')
const { join, extname } = require('path')
const { promisify } = require('util')

const statAsync = promisify(fs.stat)
const fileExists = async file => statAsync(file)
  .then(() => true)
  .catch(() => false)

const mimeTypes = {
  html: 'text/html',
  jpeg: 'image/jpeg',
  jpg: 'image/jpeg',
  png: 'image/png',
  svg: 'image/svg+xml',
  js: 'text/javascript',
  css: 'text/css',
  map: 'application/octet-stream',
  ttf: 'font/ttf',
  otf: 'font/otf',
  json: 'application/json'
}

const port = process.env.PORT || 1337
const storage = process.env.STORAGE
const serveSPA = process.env.SERVE_SPA === 'true'

http.createServer(async (req, res) => {
  const pathname = url.parse(req.url).pathname
  const uri = pathname === '/' ? 'index.html' : pathname
  let filename = join(storage, uri)
  const exists = await fileExists(filename)
  if (!exists) {
    if (!serveSPA) {
      console.log('not found:' + filename)
      res.writeHead(404, { 'Content-Type': 'text/plain' })
      res.write('404 Not Found\n')
      res.end()
      return
    }
    else {
      filename = join(storage, 'index.html')
    }
  }
  const mimeType = mimeTypes[extname(filename).split('.')[1]]
  res.writeHead(200, {
    'Content-Type': mimeType
  })

  const fileStream = fs.createReadStream(filename)
  fileStream.pipe(res)
}).listen(port)