next.config.js

module.exports = {
  reactStrictMode: true,
  productionBrowserSourceMaps: false,
  swcMinify: true,
  compiler: {
    // ssr and displayName are configured by default
    styledComponents: true,
    reactRemoveProperties: false,
  },
  async headers() {
    return [
      {
        source: "/",
        headers: [
          {
            key: "Cache-Control",
            value: "s-maxage=1, stale-while-revalidate",
          },
          ...securityHeaders,
        ],
      },
      {
        source: "/:path*",
        headers: [
          {
            key: "Cache-Control",
            value: "s-maxage=1, stale-while-revalidate",
          },
          ...securityHeaders,
        ],
      },
    ];
  },
};

// https://securityheaders.com
const scriptSrc = [
  "'self'",
  "'unsafe-eval'",
  "'unsafe-inline'",
  "*.youtube.com",
  "*.google-analytics.com",
  "*.vercel-insights.com",
  "*.vercel.app",
  "*.googletagmanager.com",
  "vercel.live",
];

const ContentSecurityPolicy = `
  default-src 'self';
  script-src ${scriptSrc.join(" ")};
  child-src *.youtube.com *.google.com *.twitter.com vercel.live;
  style-src 'self' 'unsafe-inline' *.googleapis.com;
  img-src * blob: data:;
  media-src 'none';
  connect-src *;
  font-src 'self' fonts.gstatic.com;
  worker-src 'self' *.vercel.app;
  manifest-src 'self' *.vercel.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; preload",
  },
  // https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Feature-Policy
  {
    key: "Permissions-Policy",
    value: "camera=(), microphone=(), geolocation=(), interest-cohort=()",
  },
];