TypeError：无法在addItemToCart读取null的属性“ push”

Question

i already tried searching throughout the forum and suggested posts but not quite what im looking for.

The issue is: When clicking on the list item, i get the error mentioned on title specifically in the cart.push(item); which is inside the function addItemToCart . which i've found is caused by not declaring the array, but i believ ei have declared it already.

The question is: Am i correctly declaring the scope of my array variable? Or is my problem regarding some other matter?

This is the html part:

 <div>
    <ul>
        <li><a class="add-to-cart" href="#" data-name="Apple" data-price="1.99">Product1</li>
    </ul>
</div>

This html part gets referenced inside the script through the next click function :

        $(".add-to-cart").click(function(event){
            event.preventDefault(); // --> Prevents page from refreshing
            var name = $(this).attr("data-name");
            var price = Number($(this).attr("data-price"));

            addItemToCart(name, price, 1);

        });

This part here is where i declare both my variables at the beginning of the JS script:

        var cart = [];
        var Item = function(name, price, count){
            this.name = name
            this.price = price
            this.count = count
        };

And this part here is also inside of my script and belongs to the function i want to execute:

function addItemToCart(name, price, count){
    for (var i in cart){
        if (cart[i].name === name){
            cart[i].count += count;
            //cart[i].count += count;
            return;
        }
    }
    var item = new Item(name, price, count);
    cart.push(item);
    saveCart();
}

3 last parts of code are inside my <scope> </scope>

Thanks in advance for any help i could recieve to solve the issue.

Answer 1

You did not define cart in the main scope. You must define cart in a scope that is a parent of the addItemToCart function scope.

Another alternative is to use

window.cart = [];

Or for node.js

global.cart = [];