Next.js Page Router not working

[chosanghyeon-dev]

After setting up and running create-next-app, I get an error saying "SyntaxError: Unexpected token 'export'". For reference, I turned off Turbo Pack in the options.

package.json

{
  "name": "playground",
  "version": "0.1.0",
  "private": true,
  "scripts": {
    "dev": "next dev",
    "build": "next build",
    "start": "next start",
    "lint": "eslint"
  },
  "dependencies": {
    "next": "15.5.4",
    "react": "19.1.0",
    "react-dom": "19.1.0"
  },
  "devDependencies": {
    "@eslint/eslintrc": "^3",
    "@tailwindcss/postcss": "^4",
    "@types/node": "^20",
    "@types/react": "^19",
    "@types/react-dom": "^19",
    "code-inspector-plugin": "^1.2.10",
    "eslint": "^9",
    "eslint-config-next": "15.5.4",
    "tailwindcss": "^4",
    "typescript": "^5"
  }
}

next.config.ts

import type { NextConfig } from "next";
import { codeInspectorPlugin } from "code-inspector-plugin";

const nextConfig: NextConfig = {
  /* config options here */
  reactStrictMode: true,
  webpack: (config) => {
    config.plugins.push(
      codeInspectorPlugin({
        bundler: "webpack",
      })
    );

    return config;
  },
};

export default nextConfig;

fyi. my create-next-app version

[chosanghyeon-dev]

Even if I change it to use turbo pack, the error is the same.

// next.config.js
import type { NextConfig } from 'next';
import { codeInspectorPlugin } from 'code-inspector-plugin';

const nextConfig: NextConfig = {
  turbopack: {
    rules: codeInspectorPlugin({
      bundler: 'turbopack',
    }),
  },
};

export default nextConfig;

[zh-lx]

If you use turbopack, you should use next dev --turbopack rather than next dev

[chosanghyeon-dev]

@zh-lx I'm getting an error even though I do as you said.

If possible, could you please test it with the latest create next app or add an example?

[chosanghyeon-dev]

@zh-lx The cause has been identified. It works correctly in the Next.js App Router but does not work in the Page Router.