next.config.js

const withPlugins = require('next-compose-plugins')
const optimizedImages = require('next-optimized-images')
const withBundleAnalyzer = require('@next/bundle-analyzer')({
  enabled: process.env.ANALYZE === 'true',
})

// You might need to insert additional domains in script-src if you are using external services
const ContentSecurityPolicy = `
  default-src 'self';
  script-src 'self' 'unsafe-eval' 'unsafe-inline' giscus.app;
  style-src 'self' 'unsafe-inline';
  img-src * blob: data:;
  media-src 'none';
  connect-src *;
  font-src 'self';
  frame-src giscus.app
`

const securityHeaders = [
  // https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP
  {
    key: 'Content-Security-Policy',
    value: ContentSecurityPolicy.replace(/\n/g, ''),
  },
  // https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Referrer-Policy
  {
    key: 'Referrer-Policy',
    value: 'strict-origin-when-cross-origin',
  },
  // https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Frame-Options
  {
    key: 'X-Frame-Options',
    value: 'DENY',
  },
  // https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Content-Type-Options
  {
    key: 'X-Content-Type-Options',
    value: 'nosniff',
  },
  // https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-DNS-Prefetch-Control
  {
    key: 'X-DNS-Prefetch-Control',
    value: 'on',
  },
  // https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Strict-Transport-Security
  {
    key: 'Strict-Transport-Security',
    value: 'max-age=31536000; includeSubDomains',
  },
  // https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Feature-Policy
  {
    key: 'Permissions-Policy',
    value: 'camera=(), microphone=(), geolocation=()',
  },
]
const basePath = '/articles'
module.exports = withPlugins([
  [
    optimizedImages,
    {
      // these are the default values so you don't have to provide them if they are good enough for your use-case.
      // but you can overwrite them here with any valid value you want.
      inlineImageLimit: 8192,
      imagesFolder: `/static/images`,
      imagesName: '[name]-[hash].[ext]',
      handleImages: ['jpeg', 'jpg', 'png', 'svg', 'webp', 'gif'],
      removeOriginalExtension: false,
      optimizeImages: true,
      optimizeImagesInDev: false,
      mozjpeg: {
        quality: 40,
      },
      optipng: {
        optimizationLevel: 7,
      },
      pngquant: false,
      gifsicle: {
        interlaced: true,
        optimizationLevel: 3,
      },
      svgo: {
        // enable/disable svgo plugins here
      },
      webp: {
        preset: 'default',
        quality: 75,
      },
    },
  ],
  [
    withBundleAnalyzer,
    {
      images: {
        disableStaticImages: true,
      },
      reactStrictMode: true,
      pageExtensions: ['js', 'jsx', 'md', 'mdx'],
      eslint: {
        dirs: ['pages', 'components', 'lib', 'layouts', 'scripts'],
      },
      async headers() {
        return [
          {
            source: '/(.*)',
            headers: securityHeaders,
          },
        ]
      },
      webpack: (config, { dev, isServer }) => {
        config.module.rules.push({
          test: /\.svg$/,
          use: ['@svgr/webpack'],
        })

        if (!dev && !isServer) {
          // Replace React with Preact only in client production build
          Object.assign(config.resolve.alias, {
            'react/jsx-runtime.js': 'preact/compat/jsx-runtime',
            react: 'preact/compat',
            'react-dom/test-utils': 'preact/test-utils',
            'react-dom': 'preact/compat',
          })
        }
        return config
      },
      basePath,
    },
  ],
])