Lambda@Edge for 301 redirect

index.mjs

export const handler = async (event, context, callback) => {
  var olduri = event.Records[0].cf.request.uri; // search for the uri in cloudfront request
  var host = event.Records[0].cf.request.headers.host.find(o => o.key === 'Host').value; // search for the host in the key-value headers
  if (host.startsWith("www.")) {
    const response = {
      status: '301',
      statusDescription: 'Moved Permanently',
      headers: {
        location: [{
          key: 'Location',
          value: "https://"+host.replace("www\.","")+olduri // append also olduri, so that also internal pages are redirected
        }]
      }
    };
    callback(null, response); // fire the redirect
  } else {
    // maybe a URL rewrite here
  }
}
;