Setting Cookies

In this example, cookies are used to count the number of access requests. When a browser accesses the Edge Functions service, the number of access requests is increased by 1.

Sample Code

// cookie name
const COOKIE_NAME = 'count';

async function handleRequest(request) {
// collected the current requests' Cookies and resolution into scope
const cookies = new Cookies(request.headers.get('cookie'));
const cookieCount = cookies.get(COOKIE_NAME);
// count increment
const count = Number(cookieCount && cookieCount.value || 0) + 1;
// update Cookie's count
cookies.set(COOKIE_NAME, String(count));

const response = new Response(`The count is: ${count}`);
// setting responded cookies
response.headers.set('Set-Cookie', getSetCookie(cookies.get(COOKIE_NAME)));
return response;

// concatenate Set-Cookie
function getSetCookie(cookie) {
const cookieArr = [

const key2name = {
expires: 'Expires',
max_age: 'Max-Age',
domain: 'Domain',
path: 'Path',
secure: 'Secure',
httponly: 'HttpOnly',
samesite: 'SameSite',

Object.keys(key2name).forEach(key => {
if (cookie[key]) {

return cookieArr.join('; ');

addEventListener('fetch', (event) => {

Sample Preview

In the address bar of the browser, enter a URL that matches a trigger rule of the edge function to preview the effect of the sample code.