How do Lambda at Edge and CloudFront Functions extend the capabilities of a CloudFront distribution?

Lambda at Edge lets you run more complex custom code, written in Node.js or Python, at CloudFront edge locations to modify requests and responses, such as personalizing content or performing authentication checks, while CloudFront Functions offer a lighter weight, faster, and cheaper option written in JavaScript for simpler tasks like URL rewrites or header manipulation, both running much closer to the user than your origin server.

function handler(event) {
    var request = event.request;
    request.uri = request.uri.replace('/old-path/', '/new-path/');
    return request;
}