使用inArray（）检查javascript数组中的数字

Question

I am building a web cart for a list of products by adding them to an array called 'oitems'. I'm using JSON syntax. The following function is designed to accept a 'quant' (product quantity), 'prod' (product id), 'name' (product name), 'price' (product price) and 'order' (an object containing the 'oitems' array). The funtion fires when someone clicks the 'add' button next to a product.

The 'prod' (product ids) range from 1-30. I want the function to add to the 'oitems' array when a new product is added and update existing quantities of a product if someone decides they want to increase the 'quant' of a 'prod' after they've added it. It does this, until the 'prod' number reaches '10' and I don't know why. I think it's getting confused between '1' and '10' but I don't know how to sort this out. Any ideas?

function updateOrder(quant, prod, name, price, order) {

    var cnt = 0;

    //loop through the array to see what we have
    $.each(order.oitems, function(x, y) {

        //see if the product is already in the array   
        if ($.inArray(prod, order.oitems[x].product) !== -1) {

            // product is already in the cart, update with new quantities
            order.oitems.splice(x, 1, {
                "quantity": quant,
                "product": prod,
                "name": name,
                "price": price
            });
            cnt++;
            feedback("You already have this product. The quantities have been updated.");
        }

    });


    if (cnt == 0) {
        order.oitems.push({
            "quantity": quant,
            "product": prod,
            "name": name,
            "price": price
        });
        feedback("This product has been added to your order.");
    }
}

Answer 1

I suspect that you're passing a string to the parameter prod of your updateOrder function. When you use $.inArray() on a string, it processes it as an array of individual characters.

More specifically, the string "10" is an array of two characters: 1 and 0. If you already have the product 1 in your array of items, then one of the tests performed is going to be this: $.inArray("10", "1") , which will pass because "1" is one of the characters that forms the string "10".

You can - and should - simplify your condition to the following:

if(prod == order.oitems[x].product) {...}