How to build next.js production?

I try to get a production build in next.js to run it on my server but I can't build next.js production build when I try

npm run build

Does anyone know how to get a prod build in next.js working correctly I did everything in the next.js documentation but always get this error below. If I do a dev build it works just fine but trying prod build results in errors.

I did also next build many times and reinstalled all node_modules packages still having this error.

it always shows me in terminal

Error: Could not find a valid build in the '/mnt/c/Users/NZXT_YOLO/Desktop/New folder (2)/learnnextjs-demo/.next' directory! Try building your app with 'next build' before starting the server.
    at Server.readBuildId (/mnt/c/Users/NZXT_YOLO/Desktop/New folder (2)/learnnextjs-demo/node_modules/next/dist/server/next-server.js:753:15)
    at new Server (/mnt/c/Users/NZXT_YOLO/Desktop/New folder (2)/learnnextjs-demo/node_modules/next/dist/server/next-server.js:80:25)
    at module.exports (/mnt/c/Users/NZXT_YOLO/Desktop/New folder (2)/learnnextjs-demo/node_modules/next/dist/server/next.js:6:10)
    at Object.<anonymous> (/mnt/c/Users/NZXT_YOLO/Desktop/New folder (2)/learnnextjs-demo/next.config.js:6:13)
    at Module._compile (internal/modules/cjs/loader.js:707:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:718:10)
    at Module.load (internal/modules/cjs/loader.js:605:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:544:12)
    at Function.Module._load (internal/modules/cjs/loader.js:536:3)
    at Module.require (internal/modules/cjs/loader.js:643:17)
    at require (internal/modules/cjs/helpers.js:22:18)
    at loadConfig (/mnt/c/Users/NZXT_YOLO/Desktop/New folder (2)/learnnextjs-demo/node_modules/next/dist/server/config.js:47:28)
    at _callee2$ (/mnt/c/Users/NZXT_YOLO/Desktop/New folder (2)/learnnextjs-demo/node_modules/next/dist/build/index.js:52:42)
    at tryCatch (/mnt/c/Users/NZXT_YOLO/Desktop/New folder (2)/learnnextjs-demo/node_modules/regenerator-runtime/runtime.js:62:40)
    at Generator.invoke [as _invoke] (/mnt/c/Users/NZXT_YOLO/Desktop/New folder (2)/learnnextjs-demo/node_modules/regenerator-runtime/runtime.js:288:22)
    at Generator.prototype.(anonymous function) [as next] (/mnt/c/Users/NZXT_YOLO/Desktop/New folder (2)/learnnextjs-demo/node_modules/regenerator-runtime/runtime.js:114:21)
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! hello-next@1.0.0 build: `next build`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the hello-next@1.0.0 build script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/kk/.npm/_logs/2018-12-10T19_58_00_588Z-debug.log

server.js

const express = require("express");
const next = require("next");

const port = parseInt(process.env.PORT, 10) || 3000;
const dev = process.env.NODE_ENV === "production";
const app = next({ dev });
const handle = app.getRequestHandler();

app.prepare().then(() => {
  const server = express();

  server.get("*", (req, res) => {
    return handle(req, res);
  });

  server.listen(port, err => {
    if (err) throw err;
    console.log(`> Ready on http://localhost:${port}`);
  });
});

next.config.js

const express = require("express");
const next = require("next");

const port = parseInt(process.env.PORT, 10) || 3000;
const dev = process.env.NODE_ENV === "production";
const app = next({ dev });
const handle = app.getRequestHandler();

app.prepare().then(() => {
  const server = express();

  server.get("/projects/:page", (req, res) => {
    const page = req.params.page;
    let file = "";
    switch (page) {
      case "example1":
        file = "/projects/example1";
        break;
      case "example2":
        file = "/projects/example2";
        break;
    }
    return app.render(req, res, file, { page });
  });

  server.get("*", (req, res) => {
    return handle(req, res);
  });

  server.listen(port, err => {
    if (err) throw err;
    console.log(`> Ready on http://localhost:${port}`);
  });
});

package.json

 {
  "name": "hello-next",
  "version": "1.0.0",
  "description": "",
  "main": "server.js",
  "scripts": {
    "dev": "node server.js",
    "build": "next build",
    "export": "next export"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "@zeit/next-sass": "^1.0.1",
    "express": "^4.16.4",
    "next": "^7.0.2",
    "react": "^16.6.3",
    "react-dom": "^16.6.3",
    "redux": "^4.0.1",
    "video-react": "^0.13.1"
  }
}

I plan to run this next.js site using node on my AWS server. But to do this I need to get production build of react.js currently I can run just a development build.

Solution

Seems your server.js config is not correct. Please try moving all you have from your next.config.js to server.js make sure the next.config.js file is empty then create a new npm run script:

"prod_start": "NODE_ENV=production node server.js"

Your package.json should then look like this:

{
  "name": "hello-next",
  "version": "1.0.0",
  "description": "",
  "main": "server.js",
  "scripts": {
    "dev": "node server.js",
    "build": "next build",
    "prod_start": "NODE_ENV=production node server.js",
    "export": "next export"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "@zeit/next-sass": "^1.0.1",
    "express": "^4.16.4",
    "next": "^7.0.2",
    "react": "^16.6.3",
    "react-dom": "^16.6.3",
    "redux": "^4.0.1",
    "video-react": "^0.13.1"
  }
}

make sure to run: npm run build && npm run prod_start

Then you should have a production build of react running using next.js

Let me know if you got question.