ES Modules in a Next.js server.js

Question

I checked a few examples from the Next.js repository

• https://github.com/zeit/next.js/tree/master/examples/custom-server-express
• https://github.com/zeit/next.js/tree/master/examples/custom-server-koa

and noticed that examples use ES Modules in React components and CommonJS modules in the server.js file. I'd like to keep my code written in one style, is it possible to use only ES Modules in a Next.js project?

Answer 1

This is sitting as a feature request in the Next.js backlog. https://github.com/zeit/next.js/issues/9607

Answer 2

According to node.js document Yes, you should save the server.js with ES6 modules with .mjs ( server.mjs ) extension and change package.json

from:

"scripts": {
  "dev": "node server.js",
  "build": "next build",
  "start": "NODE_ENV=production node server.js"
},

to:

"scripts": {
  "dev": "node --experimental-modules server.mjs",
  "build": "next build",
  "start": "NODE_ENV=production node --experimental-modules server.mjs"
},