Need help with Worker and cookies

Hello all,
I’m new to Worker and dont have much knowledge with cookies settings

My goal is to:

  1. i want to check if a certain cookie exists,
  2. if it does, then continue to page normally (no more processing is needed).
  3. if the cookie is missing, first check for a certain querystring,
  4. if that is missing too, then redirect to a different page. (this page will eventually send the user back to the original page - this time WITH the correct querystring)
  5. if the querystring does exist, i want to use it to set a new cookie, then reload the page - with the new cookie - returning to step 1 (this time it should pass the cookie check)

My unsuccessful Worker code:

addEventListener(‘fetch’, event => {
event.respondWith(fetchAndApply(event.request))
})

async function fetchAndApply(request) {
console.log(“started processing”)
// Forward request to origin, get response.
let response = await fetch(request)

 ////// Copy Response object so that we can edit headers.
 response = new Response(response.body, response)

///// // Check for cookie.
 let cookies = request.headers.get('Cookie') || ""
 if (cookies.includes("myCookie=true")) {
     console.log("the cookie is already set")
     return fetch(request)
 }
 else{
     console.log("no cookie was found")
     const init = {
     method: request.method,
     headers: request.headers
   }
   let qrystring = new URL(request.url).searchParams.get('qrystring');
   console.log("qrystring: " + qrystring)
   if(qrystring === null){
     console.log("didnt find a querystring, redirecting")
     return fetch(new Request('http://somewhereelse.com/somepage.html', init));
   }
   else{
     console.log("found the querystring, setting the cookie")
     var now = new Date();
     var time = now.getTime();
     var expireTime = time + 1000*36000;
     now.setTime(expireTime);
     response.headers.set("Set-Cookie", "myCookie=true;expires=" + now.toGMTString())
     return response
}

}
}

The problem is:
i think the cookie is not created (cant see it in chrome’s inspect->storage->cookies)

  1. opening the page without cookie AND without query-string redirects to the other page successfully.
  2. opening the page WITH the query-string continues to the page BUT no cookie is created, so removing the query-string again behaves the same as original step.

Thank you all in advance!!
Ram