next.config.js

const isProd = process.env.NODE_ENV === 'production'

/** @type {import('next').NextConfig} */
const nextConfig = {
    /**
   * Enable static exports for the App Router.
   *
   * @see https://nextjs.org/docs/pages/building-your-application/deploying/static-exports
   */
  output: "export",
  /**
   * Set base path. This is usually the slug of your repository.
   *
   * @see https://nextjs.org/docs/app/api-reference/next-config-js/basePath
   */
  basePath: isProd? "/nextjs-ghpages": undefined,

  /** 
   * Set asset prefix. This is usually the slug of your repository.
   * 
   * @see https://nextjs.org/docs/pages/api-reference/next-config-js/assetPrefix
   */
  assetPrefix: isProd ? "/nextjs-ghpages/": undefined,

  /**
   * Disable server-based image optimization. Next.js does not support
   * dynamic features with static exports.
   *
   * @see https://nextjs.org/docs/pages/api-reference/components/image#unoptimized
   */
  images: {
    unoptimized: true,
  },
}

module.exports = nextConfig