Работа с cookie используя JS

cookie.js

// Установка cookie
function setCookie(cookieName, cookieValue, expirationDays) {
    let d = new Date();
    d.setTime(d.getTime() + (expirationDays * 24 * 60 * 60 * 1000));
    let expires = "expires=" + d.toUTCString();
    document.cookie = cookieName + "=" + cookieValue + ";" + expires + ";path=/";
}

// Получение cookie
function getCookie(cookieName) {
    const name = cookieName + "=";
    const decodedCookie = decodeURIComponent(document.cookie);
    const cookieArray = decodedCookie.split(';');

    for(let i = 0; i < cookieArray.length; i++) {
        let cookie = cookieArray[i];
        while (cookie.charAt(0) === ' ') {
            cookie = cookie.substring(1);
        }
        if (cookie.indexOf(name) === 0) {
            return cookie.substring(name.length, cookie.length);
        }
    }

    return "";
}