I have a bug and I don't see where is the problem.

Context -> I have created a method so the user can increase and decrease the items in the card by pressing a button or by adding the number manually.

The problem comes when the user modifies the number of items manually.

This is the method:

 Future<void> setProductQuantity({
    @required Product product,
    @required String cartId,
    @required int quantity,
  }) async {
    Cart cart = getCart(cartId) ?? _createCart(cartId: cartId, products: [product]);
    Product productInCart = cart.getProductForId(product.id);

    if (productInCart != null) {
      if (quantity == 0) {
        cart.products.remove(productInCart);
      } else {
        productInCart.quantity = quantity;
      }
    } else {
      product.quantity = quantity;
      cart.products.add(product);
    }
    await persistCart(cart);
  }

The problem is if one of the items is more than 0 and the rest are 0, the items with 0 quantity gets added as well to the card. I would like to avoid that to happen.

Can anyone see where the problem is?

CodePudding user response：

Inside the else condition check for the quantity and add it to the cart only if it's higher than 0. That way you any item with quality 0 will not be added to the cart.