next.config.js

module.exports = {
  future: {
    strictPostcssConfiguration: true,
  },
  reactStrictMode: true,
  images: {
    domains: [
      'i.scdn.co', // Spotify Album Art
      'pbs.twimg.com', // Twitter Profile Picture
    ],
  },
  async headers() {
    return [
      {
        source: '/(.*)',
        headers: securityHeaders,
      },
    ]
  }
}

// https://securityheaders.com
const ContentSecurityPolicy = `
  default-src 'self';
  script-src 'self' 'unsafe-eval' 'unsafe-inline' *.youtube.com *.twitter.com cdn.usefathom.com;
  child-src *.youtube.com *.google.com *.twitter.com;
  style-src 'self' 'unsafe-inline' *.googleapis.com;
  img-src * blob: data:;
  media-src 'none';
  connect-src *;
  font-src 'self';
`

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: '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
  // Opt-out of Google FLoC: https://amifloced.org/
  {
    key: 'Permissions-Policy',
    value: 'camera=(), microphone=(), geolocation=(), interest-cohort=()',
  },
]