cookie动态存删js购物车

function addToCart(productId, productName) {
    let cart = getCart();
    let item = { productId: productId, productName: productName };
    
    // 检查商品是否已存在
    let existingItem = cart.find(item => item.productId === productId);
    if (existingItem) {
        existingItem.quantity += 1;
    } else {
        item.quantity = 1;
        cart.push(item);
    }
    
    // 更新 Cookie
    setCookie('cart', JSON.stringify(cart), 7); // 设置过期时间为7天
}

function getCart() {
    let cartStr = getCookie('cart');
    return cartStr ? JSON.parse(cartStr) : [];
}

function setCookie(name, value, days) {
    let expires = "";
    if (days) {
        let date = new Date();
        date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
        expires = "; expires=" + date.toUTCString();
    }
    document.cookie = name + "=" + (value || "") + expires + "; path=/";
}

function getCookie(name) {
    let nameEQ = name + "=";
    let ca = document.cookie.split(';');
    for(let i=0;i < ca.length;i++) {
        let c = ca[i];
        while (c.charAt(0)==' ') c = c.substring(1,c.length);
        if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
    }
    return null;
}

function removeFromCart(productId) {
    let cart = getCart();
    cart = cart.filter(item => item.productId !== productId);
    
    // 更新 Cookie
    setCookie('cart', JSON.stringify(cart), 7);
}