Example how to redirect client to new location with AWS CloudFront Function. E.g. when you deleted NextJS page, but still want to redirect clients (Native app or Search index) to new location.

aws.CloudFront.Functions.301Redirect.js

// NOTE: Choose "viewer request" for event trigger when you associate this function with CloudFront distribution.

/** See also:
- JS Specs: https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/functions-javascript-runtime-features.html
- The request Specs: https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/functions-event-structure.html
*/

function makeRedirectResponse(location) {
    var response = {
        statusCode: 301,
        statusDescription: 'Moved Permanently',
        headers: {
            'location': { value: location }
        }
    };
    return response;
}

function handler(event) {

    var mappings = [
        { from: "/products/decode/app.html", to: '/products/decode.html' },
        { from: "/products/decode/privacy/2021_01_25.html", to: '/products/decode/privacy.html' }
    ];
    
    var request = event.request;
    var uri = request.uri;
    for (var i = 0; i < mappings.length; i++) {
        var mapping = mappings[i]
        if (mapping.from === uri) {
            return makeRedirectResponse(mapping.to)
        }
    }
    return request;
}