JavaScript Examples - Extract Cookie Value

Get the value of a cookie according to its name. Can be helpful for A/B testing.

const COOKIE_NAME = "hubspotutk"
function getCookie(request, name) {
let result = ""
const cookieString = request.headers.get("Cookie")
if (cookieString) {
const cookies = cookieString.split(";")
cookies.forEach(cookie => {
const cookiePair = cookie.split("=", 2)
const cookieName = cookiePair[0].trim()
if (cookieName === name) {
const cookieVal = cookiePair[1]
result = cookieVal
}
})
}
return result
}
function handleRequest(request) {
const cookie = getCookie(request, COOKIE_NAME)
if (cookie) {
return new Response(cookie)
}
return new Response("No cookie with name: " + COOKIE_NAME)
}
addEventListener("fetch", event => {
event.respondWith(handleRequest(event.request))
})

Contributors