Add another function to methods section of cart.js called checkOut. It should:

• Create a Sale domain object. The following code shows you how to do this:

   let sale = new Sale(this.customer, this.items);

• POST the sale object to the /api/sales path of the web service.

• Reset the items array to prevent accidental double orders. The following data store mutation can be used to do this:

    // clear cart items
    clearItems(state) {
        state.items = new Array();
    }

  Call the mutation via the usual commit call in the then callback of the Axios request.