努力添加购物车本地存储逻辑

Question

   $scope.toCart = function(id,item){

      var toSaveArray = [];
      var toSaveObj = {
        id: item._id,
        name : item.name,
        image : item.image[0],
        price : item.price,
        discount_price : item.discount_price,
        qty : 1
      }

      toSaveArray.push(toSaveObj);

      var fromSaved = JSON.parse(localStorage.getItem('cart'));

      if(fromSaved){
          for(i=0;i<fromSaved.length;i++){
          if(fromSaved[i].id == id){
            fromSaved[i].qty += 1;
            toSaveArray.push(fromSaved);
          }
        }
      }

      localStorage.setItem('cart',JSON.stringify(toSaveArray));

   }

如果项目存在，请添加一个数量，否则只需将对象添加到数组中。但是由于这个简单的逻辑，我没有一个有效的代码。上面的代码已经破了。

Answer 1

我解决了一些逻辑错误：

$scope.toCart = function(id, item) {
    var cart = JSON.parse(localStorage.getItem('cart'));
    if (!cart) {
        cart = [];
    }

    var index = cart.findIndex(function (cartItem) {
        return cartItem.id === item._id;
    });

    if (index !== -1) {
        cart[index].qty += 1;
    } else {
        cart.push({
            id: item._id,
            name : item.name,
            image : item.image[0],
            price : item.price,
            discount_price : item.discount_price,
            qty : 1
        });
    }

    localStorage.setItem('cart',JSON.stringify(cart));

}

Answer 2

您的代码在这些步骤上做错了：

• 比较之前的item._id与参数id
• 始终保存item参数

• 为

  执行不必要的

  $scope.toCart = function(item){
  
      var toSaveArray = [];
      var toSaveObj = {
          id: item._id,
          name : item.name,
          image : item.image[0],
          price : item.price,
          discount_price : item.discount_price,
          qty : 1
      };
  
      var fromSaved = JSON.parse(localStorage.getItem('cart'));
  
      if(fromSaved){
          var savedItem = $filter('filter')(fromSaved, {id: item._id});
          if (savedItem) {
              fromSaved[fromSaved.indexOf(savedItem[0])].qty++;
          }
  
          toSaveArray = fromSaved;
      } else {
          toSaveArray.push(toSaveObj);
      }
  
      localStorage.setItem('cart',JSON.stringify(toSaveArray));
  };
  

以上代码应涵盖所有内容。