NextJS Custom Server definition for use with Heroku NGINX buildpack

server.js

const { createServer } = require('http')
const { parse } = require('url')
const next = require('next')
const fs = require('fs');

const dev = process.env.NODE_ENV !== 'production'
const app = next({ dev })
const handle = app.getRequestHandler()

app.prepare().then(() => {
    createServer((req, res) => {
        const parsedUrl = parse(req.url, true)
        handle(req, res, parsedUrl)
    }).listen('/tmp/nginx.socket', (err) => {
        if (err) throw err
        console.log('> NextJS Server running...')
        fs.openSync('/tmp/app-initialized', 'w');
    })
})