server.ts

import path from 'path'
import express from 'express'
import compression from 'compression'
import morgan from 'morgan'
import { createRequestHandler } from '@remix-run/express'
import { startBackgroundProcessing } from '~/background-process.server'

const BUILD_DIR = path.join(process.cwd(), 'build/index.js')

const app = express()

startBackgroundProcessing()

app.use(compression())

// http://expressjs.com/en/advanced/best-practice-security.html#at-a-minimum-disable-x-powered-by-header
app.disable('x-powered-by')

// Remix fingerprints its assets so we can cache forever.
app.use('/build', express.static('public/build', { immutable: true, maxAge: '1y' }))

// Everything else (like favicon.ico) is cached for an hour. You may want to be
// more aggressive with this caching.
app.use(express.static('public', { maxAge: '1h' }))

app.use(morgan('tiny'))

app.all(
	'*',
	process.env.NODE_ENV === 'development'
		? (req: any, res: any, next: any) => {
			purgeRequireCache()

			return createRequestHandler({
				build: require(BUILD_DIR),
				mode: process.env.NODE_ENV,
			})(req, res, next)
		}
		: createRequestHandler({
			build: require(BUILD_DIR),
			mode: process.env.NODE_ENV,
		}),
)
const port = process.env.PORT || 3000

app.listen(port, () => {
	require(BUILD_DIR)
	console.log(`Express server listening on port ${port}`)
})

function purgeRequireCache() {
	// purge require cache on requests for "server side HMR" this won't let
	// you have in-memory objects between requests in development,
	// alternatively you can set up nodemon/pm2-dev to restart the server on
	// file changes, but then you'll have to reconnect to databases/etc on each
	// change. We prefer the DX of this, so we've included it for you by default
	for (let key in require.cache) {
		if (key.startsWith(BUILD_DIR)) {
			delete require.cache[key]
		}
	}
}