如何计算购物车产品运费

Question

I have products in a cart from different sellers with different shipping prices.

what would be the way to calculate the shipping?

This is what I have so far: I initialize the variable shipping:

public shipping: number;

Then I do a foreach for the shopping cart

  this.cart.forEach(item => {
        this.shipping += item.product.shippingCost;
    });

The above is giving me shipping to be 'NAN'.

What would be the way to do this, considering if products are from different sellers.

I am not sure of the real way to go about this.

For example, If different kind of goods (product 1: a book, product 2: a car), are in the cart with different shipping requirements but from the same seller. Do I have to calculate the shipping for such product differently? Considering this same seller can just bundle the car and the book to one package.

What should be the way to calculate shipping for such a client listing site sale shopping cart?

Answer 1

Initialize "this.shipping" with 0 before adding values in it.

Edit1: before this loop, use this statement.

this.shipping = 0

Answer 2

You can use map and reduce to avoid initialize value

 this.cart
.map(item => Number(item.product.shippingCost))
.reduce((prev, next) => prev + next);

if you have seller id in this object then you can filter by seller id

 this.cart
.filter(item => item.seller_id === SELLER_ID)
.map(item => Number(item.product.shippingCost))
.reduce((prev, next) => prev + next);

Note : SELLER_ID is your specific seller id