simple ExpressJS spa

server.js

const express = require('express')
const bodyParser = require('body-parser')
const path = require('path')

const app = express()

// assets. Static JS, CSS, fonts
app.use('/public', express.static(path.join(__dirname, '../public')))
app.use(bodyParser.urlencoded({ extended: false }))
app.use(bodyParser.json())

// SPA default configuration
// it is important to declare this after the assets rule
app.get('*', (req, res, next) => {
	res.sendFile('path to your html file')
})

// start server
const server = app.listen(process.env.PORT || 3000, () => {
	console.log(`server running on port ${server.address().port}`)
})

Then the start script in package.json should be something like node ./server/server.js