Cookie based routing on CloudFront

Hello All!

I'm trying to route traffic based on a cookie with a Lambda function. But getting this error message when I test it and I couldn't figured out why. I would be glad if anyone can point me to right direction.

ERROR Invoke Error {"errorType":"TypeError","errorMessage":"Cannot read properties of undefined (reading 's3')","stack":["TypeError: Cannot read properties of undefined (reading 's3')"," at Runtime.exports.handler (/var/task/index.js:16:32)"," at Runtime.handleOnce (file:///var/runtime/index.mjs:548:29)"]}

or it says "Cannot read properties of undefined (reading 'custom')" when I send another cookie value.

My code is this and using runtime Node.Js 16.x

'use strict';

exports.handler = (event, context, callback) => {
    const request = event.Records[0].cf.request;

    //Setup the two different origins
    const originA = '<s3 origin url>';
    const originB = '<load balancer url>';

	//check v2=true cookie if exists
    if (request.headers.cookie) {
        for (let i = 0; i < request.headers.cookie.length; i++) {
            if (request.headers.cookie[i].value === 'v2=true') {
                console.log('Origin A cookie found');
                request.headers['host'] = [{key: 'host', value: originA}];
                request.origin.s3.domainName = originA;
                break;
            } 
            else {
                console.log('Origin B cookie found');
                request.headers['host'] = [{key: 'host', value: originB}];
                request.origin.custom.domainName = originB;
                break;
            }
        }
    }
    
        callback(null, request);
};

I am testing it with the below code.

{
  "Records": [
    {
      "cf": {
        "config": {
          "distributionId": "<my distrubitonid>"
        },
        "request": {
          "uri": "/",
          "method": "GET",
          "clientIp": "<my ip>",
          "headers": {
            "cookie": [
              {
                "key": "Cookie",
                "value": "v2=true"
              }
            ]
          }
        }
      }
    }
  ]
}