Redirect non-www to www url in AWS CloudFront

aws-cloudfront-function-www-to-non-www.js

// Create function in
//   cloudfront /
//     functions
// Create distribution in
//   cloudfront /
//     distributions
// Associate function to distribution in
//   cloudfront /
//     distributions /
//       YOUR_DIST /
//         behaviors /
//           new behavior /
//             function associations /
//               viewer request
function handler(event) {
  const request = event.request;
  const headers = request.headers;
  // Check if the request is for www.example.com
  if (headers.host && headers.host.value.startsWith('www.')) {
    // Redirect to non-www URL
    const redirectUrl = 'https://' + headers.host.value.replace(/^www\./, '') + request.uri;
    // Create a 301 (permanent) redirect response
    const response = {
      statusCode: 301,
      statusDescription: 'Moved Permanently',
      headers: {
       "location": { "value": redirectUrl }
      }
    };
    // Return the response to perform the redirect
    return response;
  }
  // If the request is not for www.example.com, continue as normal
  return request;
}