[Vue.js] Adding computed classes

//JS
computed: {
	cartTotal: function() {
    	let sum = 0;
        for (key in this.cart) {
        	sum = sum+this.cart[key].product.price * this.cart[key].qty);
        }
        return sum;
    },
    cartQty: function() {
    	let qty = 0;
        for (key in this.cart) {
        	qty = qty+this.cart[key].qty);
        }
        return qty;
    }
}