old_contents: const path = require('path')
  const express = require('express')
  const cache = require('cache-control')
  
  const app = express()
  
  app.use(cache({
    // don't cache html
    '/**/*.html': 'public, max-age=0',
    // cache all other files for a year
    '/**': '1y'
  }))
  
  // don't identify as an express server
  app.disable('x-powered-by')
  
  // serve all static files from the /public folder
  app.use(express.static(path.join(__dirname, 'public')))
  
  // serve index.html for all routes
  app.get('*', (req, res) => {
    res.sendFile(path.join(__dirname, 'public/index.html'))
  })
  
  // listen on port 80
  app.listen(80)
  
new_contents: const path = require('path')
  const express = require('express')
  const cache = require('cache-control')
  
  const app = express()
  
  app.use(cache({
    // don't cache html
    '/**/*.html': 0,
    // cache all other files for a year (in seconds)
    '!/**/*.html': 60 * 60 * 24 * 365
  }))
  
  // don't identify as an express server
  app.disable('x-powered-by')
  
  // serve all static files from the /public folder
  app.use(express.static(path.join(__dirname, 'public')))
  
  // serve index.html for all routes
  app.get('*', (req, res) => {
    res.sendFile(path.join(__dirname, 'public/index.html'))
  })
  
  // listen on port 80
  app.listen(80)
  
subject: Fix cache (#102)